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authorBoris Kolpackov <boris@codesynthesis.com>2024-02-06 05:22:12 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2024-02-06 15:29:55 +0200
commit2269a611da40bd7242dbd1a3204c212ac6091fd7 (patch)
tree762f9eba621026e9bb7d8fd69107a4447783a45a /libbuild2
parenta5acaba537dab8e06be1197916acff86699aa5a3 (diff)
Add experimental support for JSON value types
Diffstat (limited to 'libbuild2')
-rw-r--r--libbuild2/function.cxx3
-rw-r--r--libbuild2/functions-json.cxx240
-rw-r--r--libbuild2/json.cxx856
-rw-r--r--libbuild2/json.hxx316
-rw-r--r--libbuild2/json.ixx222
-rw-r--r--libbuild2/parser.cxx124
-rw-r--r--libbuild2/variable.cxx926
-rw-r--r--libbuild2/variable.hxx61
-rw-r--r--libbuild2/variable.ixx107
9 files changed, 2831 insertions, 24 deletions
diff --git a/libbuild2/function.cxx b/libbuild2/function.cxx
index f979d92..3110547 100644
--- a/libbuild2/function.cxx
+++ b/libbuild2/function.cxx
@@ -355,6 +355,7 @@ namespace build2
void builtin_functions (function_map&); // functions-builtin.cxx
void filesystem_functions (function_map&); // functions-filesystem.cxx
void integer_functions (function_map&); // functions-integer.cxx
+ void json_functions (function_map&); // functions-json.cxx
void name_functions (function_map&); // functions-name.cxx
void path_functions (function_map&); // functions-path.cxx
void process_functions (function_map&); // functions-process.cxx
@@ -365,6 +366,7 @@ namespace build2
void target_triplet_functions (function_map&); // functions-target-triplet.cxx
void project_name_functions (function_map&); // functions-target-triplet.cxx
+
void
insert_builtin_functions (function_map& m)
{
@@ -372,6 +374,7 @@ namespace build2
builtin_functions (m);
filesystem_functions (m);
integer_functions (m);
+ json_functions (m);
name_functions (m);
path_functions (m);
process_functions (m);
diff --git a/libbuild2/functions-json.cxx b/libbuild2/functions-json.cxx
new file mode 100644
index 0000000..7551fa1
--- /dev/null
+++ b/libbuild2/functions-json.cxx
@@ -0,0 +1,240 @@
+// file : libbuild2/functions-json.cxx -*- C++ -*-
+// license : MIT; see accompanying LICENSE file
+
+#include <libbuild2/function.hxx>
+#include <libbuild2/variable.hxx>
+
+#ifndef BUILD2_BOOTSTRAP
+# include <libbutl/json/parser.hxx>
+# include <libbutl/json/serializer.hxx>
+#endif
+
+using namespace std;
+
+namespace build2
+{
+ static size_t
+ find_index (const json_value& a, value v)
+ {
+ if (a.type != json_type::array)
+ fail << "expected json array instead of " << to_string (a.type)
+ << " as first argument";
+
+ auto b (a.array.begin ()), e (a.array.end ());
+ auto i (find (b, e, convert<json_value> (move (v))));
+ return i != e ? i - b : a.array.size ();
+ };
+
+ void
+ json_functions (function_map& m)
+ {
+ function_family f (m, "json");
+
+ // $value_type(<json>[, <distinguish_numbers>])
+ //
+ // Return the type of a JSON value: `null`, `boolean`, `number`, `string`,
+ // `array`, or `object`. If the <distinguish_numbers> argument is `true`,
+ // then instead of `number` return `signed number`, `unsigned number`, or
+ // `hexadecimal number`.
+ //
+ f["value_type"] += [] (json_value v, optional<value> distinguish_numbers)
+ {
+ bool dn (distinguish_numbers &&
+ convert<bool> (move (*distinguish_numbers)));
+
+ return to_string (v.type, dn);
+ };
+
+ // $member_name(<json>)
+ //
+ // Return the name of a JSON object member.
+ //
+ f["member_name"] += [] (json_value v)
+ {
+ // A member becomes an object with a single member (see json_reverse()
+ // for details).
+ //
+ if (v.type == json_type::object && v.object.size () == 1)
+ return move (v.object.front ().name);
+
+ fail << "json object member expected instead of " << v.type << endf;
+ };
+
+ // $member_value(<json>)
+ //
+ // Return the value of a JSON object member.
+ //
+ f["member_value"] += [] (json_value v)
+ {
+ // A member becomes an object with a single member (see json_reverse()
+ // for details).
+ //
+ if (v.type == json_type::object && v.object.size () == 1)
+ return move (v.object.front ().value);
+
+ fail << "json object member expected instead of " << v.type << endf;
+ };
+
+ // $size(<json>)
+ //
+ // Return the size of a JSON value.
+ //
+ // The size of a `null` value is `0`. The sizes of simple values
+ // (`boolean`, `number`, and `string`) is `1`. The size of `array` and
+ // `object` values is the number of elements and members, respectively.
+ //
+ // Note that the size of a `string` JSON value is not the length of the
+ // string. To get the length call `$string.size()` instead by casting the
+ // JSON value to the `string` value type.
+ //
+ f["size"] += [] (json_value v) -> size_t
+ {
+ // Note: should be consistent with value_traits<json_value>::empty(),
+ // json_subscript().
+ //
+ switch (v.type)
+ {
+ case json_type::null: return 0;
+ case json_type::boolean:
+ case json_type::signed_number:
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ case json_type::string: break;
+ case json_type::array: return v.array.size ();
+ case json_type::object: return v.object.size ();
+ }
+
+ return 1;
+ };
+
+ // $find(<json-array>, <json>)
+ //
+ // Return true if the JSON array contains the specified JSON value.
+ //
+ f["find"] += [](json_value a, value v)
+ {
+ size_t i (find_index (a, move (v)));
+ return i != a.array.size (); // We now know it's an array.
+ };
+
+ // $find_index(<json-array>, <json>)
+ //
+ // Return the index of the first element in the JSON array that is equal
+ // to the specified JSON value or `$size(json-array)` if none is found.
+ //
+ f["find_index"] += [](json_value a, value v)
+ {
+ return find_index (a, move (v));
+ };
+
+#ifndef BUILD2_BOOTSTRAP
+
+ // @@ Flag to support multi-value (returning it as JSON array)? Then
+ // probably also in $serialize().
+ //
+ // @@ Flag to override duplicates instead of failing?
+
+ // $json.load(<path>)
+ //
+ // Parse the contents of the specified file as JSON input text and return
+ // the result as a value of the `json` type.
+ //
+ // See also `$json.parse()`.
+ //
+ // Note that this function is not pure.
+ //
+ f.insert (".load", false) += [] (names xf)
+ {
+ path f (convert<path> (move (xf)));
+
+ try
+ {
+ ifdstream is (f);
+ json_parser p (is, f.string ());
+ return json_value (p);
+ }
+ catch (const invalid_json_input& e)
+ {
+ fail (location (f, e.line, e.column)) << "invalid json input: " << e <<
+ info << "byte offset " << e.position << endf;
+ }
+ catch (const io_error& e)
+ {
+ fail << "unable to read from " << f << ": " << e << endf;
+ }
+ };
+
+ // $json.parse(<text>)
+ //
+ // Parse the specified JSON input text and return the result as a value of
+ // the `json` type.
+ //
+ // See also `$json.load()` and `$json.serialize()`.
+ //
+ f[".parse"] += [] (names text)
+ {
+ string t (convert<string> (move (text)));
+
+ try
+ {
+ json_parser p (t, nullptr /* name */);
+ return json_value (p);
+ }
+ catch (const invalid_json_input& e)
+ {
+ fail << "invalid json input: " << e <<
+ info << "line " << e.line
+ << ", column " << e.column
+ << ", byte offset " << e.position << endf;
+ }
+ };
+
+ // $serialize(<json>[, <indentation>])
+ //
+ // Serialize the specified JSON value and return the resulting JSON output
+ // text.
+ //
+ // The optional <indentation> argument specifies the number of indentation
+ // spaces that should be used for pretty-printing. If `0` is passed, then
+ // no pretty-printing is performed. The default is `2` spaces.
+ //
+ // See also `$json.parse()`.
+ //
+ f["serialize"] += [] (json_value v, optional<value> indentation)
+ {
+ uint64_t i (indentation ? convert<uint64_t> (*indentation) : 2);
+
+ try
+ {
+ // For the diagnostics test.
+ //
+#if 0
+ if (v.type == json_type::string && v.string == "deadbeef")
+ {
+ v.string[4] = 0xe0;
+ v.string[5] = 0xe0;
+ }
+#endif
+
+ string o;
+ json_buffer_serializer s (o, i);
+ v.serialize (s);
+ return o;
+ }
+ catch (const invalid_json_output& e)
+ {
+ diag_record dr;
+ dr << fail << "invalid json value: " << e;
+
+ if (e.event)
+ dr << info << "while serializing " << to_string (*e.event);
+
+ if (e.offset != string::npos)
+ dr << info << "offending byte offset " << e.offset;
+
+ dr << endf;
+ }
+ };
+#endif
+ }
+}
diff --git a/libbuild2/json.cxx b/libbuild2/json.cxx
new file mode 100644
index 0000000..f368679
--- /dev/null
+++ b/libbuild2/json.cxx
@@ -0,0 +1,856 @@
+// file : libbuild2/json.cxx -*- C++ -*-
+// license : MIT; see accompanying LICENSE file
+
+#include <libbuild2/json.hxx>
+
+#include <limits>
+
+#ifndef BUILD2_BOOTSTRAP
+# include <libbutl/json/parser.hxx>
+# include <libbutl/json/serializer.hxx>
+#endif
+
+namespace build2
+{
+ // json_event
+ //
+#ifndef BUILD2_BOOTSTRAP
+ const char*
+ to_string (json_event e)
+ {
+ switch (e)
+ {
+ case json_event::begin_object: return "beginning of object";
+ case json_event::end_object: return "end of object";
+ case json_event::begin_array: return "beginning of array";
+ case json_event::end_array: return "end of array";
+ case json_event::name: return "member name";
+ case json_event::string: return "string value";
+ case json_event::number: return "numeric value";
+ case json_event::boolean: return "boolean value";
+ case json_event::null: return "null value";
+ }
+
+ return "";
+ }
+#endif
+
+ // json_type
+ //
+ const char*
+ to_string (json_type t, bool dn) noexcept
+ {
+ using type = json_type;
+
+ switch (t)
+ {
+ case type::null: return "null";
+ case type::boolean: return "boolean";
+ case type::signed_number: return dn ? "signed number" : "number";
+ case type::unsigned_number: return dn ? "unsigned number" : "number";
+ case type::hexadecimal_number: return dn ? "hexadecimal number" : "number";
+ case type::string: return "string";
+ case type::array: return "array";
+ case type::object: return "object";
+ }
+ return "";
+ }
+
+ // json_value
+ //
+ const json_value null_json_value (json_type::null);
+
+ [[noreturn]] void
+ at_throw (json_type t, json_type e, bool index)
+ {
+ string m;
+
+ if (t != e && t != json_type::null)
+ {
+ m = "expected ";
+ m += to_string (e);
+ m += " instead of ";
+ m += to_string (t);
+ throw invalid_argument (move (m));
+ }
+ else
+ {
+ m = index ? "index" : "name";
+ m += " out of range in ";
+ m += to_string (e);
+ throw std::out_of_range (move (m));
+ }
+ }
+
+ const json_value& json_value::
+ at (size_t index) const
+ {
+ if (type == json_type::array)
+ {
+ if (index < array.size ())
+ return array[index];
+ }
+
+ at_throw (type, json_type::array, true);
+ }
+
+ json_value& json_value::
+ at (size_t index)
+ {
+ if (type == json_type::array)
+ {
+ if (index < array.size ())
+ return array[index];
+ }
+
+ at_throw (type, json_type::array, true);
+ }
+
+ const json_value& json_value::
+ operator[] (size_t index) const
+ {
+ if (type == json_type::null)
+ return null_json_value;
+
+ if (type == json_type::array)
+ return index < array.size () ? array[index] : null_json_value;
+
+ at_throw (type, json_type::array, true);
+ }
+
+ json_value& json_value::
+ operator[] (size_t index)
+ {
+ if (type == json_type::null)
+ {
+ new (&array) array_type ();
+ type = json_type::array;
+ }
+
+ if (type == json_type::array)
+ {
+ size_t n (array.size ());
+
+ if (index < n)
+ return array[index];
+
+ // If there are missing elements in between, fill them with nulls.
+ //
+ if (index != n)
+ array.resize (index, json_value ());
+
+ array.push_back (json_value ());
+ return array.back ();
+ }
+
+ at_throw (type, json_type::array, true);
+ }
+
+ const json_value& json_value::
+ at (const char* name) const
+ {
+ if (type == json_type::object)
+ {
+ auto i (find_if (object.begin (), object.end (),
+ [name] (const json_member& m)
+ {
+ return m.name == name;
+ }));
+
+ if (i != object.end ())
+ return i->value;
+ }
+
+ at_throw (type, json_type::object, false);
+ }
+
+ json_value& json_value::
+ at (const char* name)
+ {
+ if (type == json_type::object)
+ {
+ auto i (find_if (object.begin (), object.end (),
+ [name] (const json_member& m)
+ {
+ return m.name == name;
+ }));
+
+ if (i != object.end ())
+ return i->value;
+ }
+
+ at_throw (type, json_type::object, false);
+ }
+
+ const json_value& json_value::
+ operator[] (const char* name) const
+ {
+ if (type == json_type::null)
+ return null_json_value;
+
+ if (type == json_type::object)
+ {
+ auto i (find_if (object.begin (), object.end (),
+ [name] (const json_member& m)
+ {
+ return m.name == name;
+ }));
+
+
+ return i != object.end () ? i->value : null_json_value;
+ }
+
+ at_throw (type, json_type::object, false);
+ }
+
+ json_value& json_value::
+ operator[] (const char* name)
+ {
+ if (type == json_type::null)
+ {
+ new (&object) object_type ();
+ type = json_type::object;
+ }
+
+ if (type == json_type::object)
+ {
+ auto i (find_if (object.begin (), object.end (),
+ [name] (const json_member& m)
+ {
+ return m.name == name;
+ }));
+
+ if (i != object.end ())
+ return i->value;
+
+ object.push_back (json_member {name, json_value ()});
+ return object.back ().value;
+ }
+
+ at_throw (type, json_type::object, false);
+ }
+
+ int json_value::
+ compare (const json_value& v) const noexcept
+ {
+ int r (0);
+ {
+ // Note: we need to treat unsigned and hexadecimal the same.
+ //
+ json_type t (type == json_type::hexadecimal_number
+ ? json_type::unsigned_number
+ : type);
+
+ json_type vt (v.type == json_type::hexadecimal_number
+ ? json_type::unsigned_number
+ : v.type);
+
+ if (t != vt)
+ {
+ // Handle the special signed/unsigned number case here.
+ //
+ if (t == json_type::signed_number &&
+ vt == json_type::unsigned_number)
+ {
+ if (signed_number < 0)
+ r = -1;
+ else
+ {
+ uint64_t u (static_cast<uint64_t> (signed_number));
+ r = u < v.unsigned_number ? -1 : (u > v.unsigned_number ? 1 : 0);
+ }
+ }
+ else if (t == json_type::unsigned_number &&
+ vt == json_type::signed_number)
+ {
+ if (v.signed_number < 0)
+ r = 1;
+ else
+ {
+ uint64_t u (static_cast<uint64_t> (v.signed_number));
+ r = unsigned_number < u ? -1 : (unsigned_number > u ? 1 : 0);
+ }
+ }
+ else
+ r = (static_cast<uint8_t> (t) < static_cast<uint8_t> (vt) ? -1 : 1);
+ }
+ }
+
+ if (r == 0)
+ {
+ switch (type)
+ {
+ case json_type::null:
+ {
+ r = 0;
+ break;
+ }
+ case json_type::boolean:
+ {
+ r = boolean == v.boolean ? 0 : boolean ? 1 : -1;
+ break;
+ }
+ case json_type::signed_number:
+ {
+ r = (signed_number < v.signed_number
+ ? -1
+ : (signed_number > v.signed_number ? 1 : 0));
+ break;
+ }
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ {
+ r = (unsigned_number < v.unsigned_number
+ ? -1
+ : (unsigned_number > v.unsigned_number ? 1 : 0));
+ break;
+ }
+ case json_type::string:
+ {
+ r = string.compare (v.string);
+ break;
+ }
+ case json_type::array:
+ {
+ auto i (array.begin ()), ie (array.end ());
+ auto j (v.array.begin ()), je (v.array.end ());
+
+ for (; i != ie && j != je; ++i, ++j)
+ {
+ if ((r = i->compare (*j)) != 0)
+ break;
+ }
+
+ if (r == 0)
+ r = i == ie ? (j == je ? 0 : -1) : 1; // More elements than other?
+
+ break;
+ }
+ case json_type::object:
+ {
+ // We don't expect there to be a large number of members so it makes
+ // sense to iterate in the lexicographical order without making any
+ // copies.
+ //
+ auto next = [] (object_type::const_iterator p, // == e for first
+ object_type::const_iterator b,
+ object_type::const_iterator e)
+ {
+ // We need to find an element with the "smallest" name that is
+ // greater than the previous entry.
+ //
+ auto n (e);
+
+ for (auto i (b); i != e; ++i)
+ {
+ if (p == e || i->name > p->name)
+ {
+ int r;
+ if (n == e || (r = n->name.compare (i->name)) > 0)
+ n = i;
+ else
+ assert (r != 0); // No duplicates.
+ }
+ }
+
+ return n;
+ };
+
+ auto ib (object.begin ()), ie (object.end ()), i (ie);
+ auto jb (v.object.begin ()), je (v.object.end ()), j (je);
+
+ for (;;)
+ {
+ // Note: we must call next() on both.
+ //
+ i = next (i, ib, ie);
+ j = next (j, jb, je);
+
+ if (i == ie || j == je)
+ break;
+
+ // Determine if both have this name and if not, which name comes
+ // first.
+ //
+ int n (i->name.compare (j->name));
+
+ r = (n < 0 // If i's first, then i is greater.
+ ? -1
+ : (n > 0 // If j's first, then j is greater.
+ ? 1
+ : i->value.compare (j->value))); // Both have this name.
+
+ if (r != 0)
+ break;
+ }
+
+ if (r == 0)
+ r = i == ie ? (j == je ? 0 : -1) : 1; // More members than other?
+
+ break;
+ }
+ }
+ }
+
+ return r;
+ }
+
+ static void
+ append_numbers (json_value& l, const json_value& r) noexcept
+ {
+ auto append = [&l] (uint64_t u, int64_t s, bool hex = false)
+ {
+ if (s < 0)
+ {
+ // The absolute value of a minimum signed intereger is not
+ // representable in the 2s complement integers. So handle this
+ // specially for completeness.
+ //
+ uint64_t a (
+ s != std::numeric_limits<int64_t>::min ()
+ ? static_cast<uint64_t> (-s)
+ : static_cast<uint64_t> (std::numeric_limits<int64_t>::max ()) + 1);
+
+ if (u >= a)
+ {
+ l.unsigned_number = u - a;
+ l.type = (hex
+ ? json_type::hexadecimal_number
+ : json_type::unsigned_number);
+ }
+ else
+ {
+ l.signed_number = -static_cast<int64_t> (a - u);
+ l.type = json_type::signed_number;
+ }
+ }
+ else
+ {
+ l.unsigned_number = u + static_cast<uint64_t> (s);
+ l.type = (hex
+ ? json_type::hexadecimal_number
+ : json_type::unsigned_number);
+ }
+ };
+
+ // We try to keep LHS hex if possible.
+ //
+ if (l.type == json_type::signed_number)
+ {
+ if (r.type == json_type::signed_number)
+ {
+ // Deal with non-negative signed numbers for completeness.
+ //
+ if (l.signed_number >= 0)
+ append (static_cast <uint64_t> (l.signed_number), r.signed_number);
+ else if (r.signed_number >= 0)
+ append (static_cast <uint64_t> (r.signed_number), l.signed_number);
+ else
+ l.signed_number += r.signed_number;
+ }
+ else
+ append (r.unsigned_number, l.signed_number);
+ }
+ else
+ {
+ if (r.type == json_type::signed_number)
+ append (l.unsigned_number,
+ r.signed_number,
+ l.type == json_type::hexadecimal_number);
+ else
+ l.unsigned_number += r.unsigned_number;
+ }
+ }
+
+ void json_value::
+ append (json_value&& v)
+ {
+ if (type == json_type::null)
+ {
+ *this = move (v);
+ return;
+ }
+ else if (type == json_type::array)
+ {
+ if (v.type == json_type::array)
+ {
+ if (array.empty ())
+ array = move (v.array);
+ else
+ array.insert (array.end (),
+ make_move_iterator (v.array.begin ()),
+ make_move_iterator (v.array.end ()));
+ }
+ else
+ array.push_back (move (v));
+
+ return;
+ }
+ else
+ {
+ switch (v.type)
+ {
+ case json_type::null: return;
+ case json_type::boolean:
+ {
+ if (type != json_type::boolean)
+ break;
+
+ boolean = boolean || v.boolean;
+ return;
+ }
+ case json_type::signed_number:
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ {
+ if (type != json_type::signed_number &&
+ type != json_type::unsigned_number &&
+ type != json_type::hexadecimal_number)
+ break;
+
+ append_numbers (*this, v);
+ return;
+ }
+ case json_type::string:
+ {
+ if (type != json_type::string)
+ break;
+
+ string += v.string;
+ return;
+ }
+ case json_type::array: break;
+ case json_type::object:
+ {
+ if (type != json_type::object)
+ break;
+
+ if (object.empty ())
+ object = move (v.object);
+ else
+ {
+ for (json_member& m: v.object)
+ {
+ auto i (find_if (object.begin (), object.end (),
+ [&m] (const json_member& o)
+ {
+ return m.name == o.name;
+ }));
+ if (i != object.end ())
+ i->value = move (m.value);
+ else
+ object.push_back (move (m));
+ }
+ }
+
+ return;
+ }
+ }
+ }
+
+ throw invalid_argument (
+ string_type ("unable to append ") + to_string (v.type) + " to " +
+ to_string (type));
+ }
+
+ void json_value::
+ prepend (json_value&& v)
+ {
+ if (type == json_type::null)
+ {
+ *this = move (v);
+ return;
+ }
+ else if (type == json_type::array)
+ {
+ if (v.type == json_type::array)
+ {
+ if (array.empty ())
+ array = move (v.array);
+ else
+ array.insert (array.begin (),
+ make_move_iterator (v.array.begin ()),
+ make_move_iterator (v.array.end ()));
+ }
+ else
+ array.insert (array.begin (), move (v));
+
+ return;
+ }
+ else
+ {
+ switch (v.type)
+ {
+ case json_type::null: return;
+ case json_type::boolean:
+ {
+ if (type != json_type::boolean)
+ break;
+
+ boolean = boolean || v.boolean;
+ return;
+ }
+ case json_type::signed_number:
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ {
+ if (type != json_type::signed_number &&
+ type != json_type::unsigned_number &&
+ type != json_type::hexadecimal_number)
+ break;
+
+ append_numbers (*this, v);
+ return;
+ }
+ case json_type::string:
+ {
+ if (type != json_type::string)
+ break;
+
+ string.insert (0, v.string);
+ return;
+ }
+ case json_type::array: break;
+ case json_type::object:
+ {
+ if (type != json_type::object)
+ break;
+
+ if (object.empty ())
+ object = move (v.object);
+ else
+ {
+ for (json_member& m: v.object)
+ {
+ auto i (find_if (object.begin (), object.end (),
+ [&m] (const json_member& o)
+ {
+ return m.name == o.name;
+ }));
+ if (i != object.end ())
+ i->value = move (m.value);
+ else
+ object.insert (object.begin (), move (m));
+ }
+ }
+
+ return;
+ }
+ }
+ }
+
+ throw invalid_argument (
+ string_type ("unable to prepend ") + to_string (v.type) + " to " +
+ to_string (type));
+ }
+
+#ifndef BUILD2_BOOTSTRAP
+ json_value::
+ json_value (json_parser& p, optional<json_type> et)
+ {
+ using namespace butl::json;
+
+ // A JSON input text cannot be empty.
+ //
+ // Once we have JSON5 support we will be able to distinguish hexadecimal
+ // numbers.
+ //
+ json_type t (json_type::null);
+ switch (*p.next ())
+ {
+ case event::begin_object: t = json_type::object; break;
+ case event::begin_array: t = json_type::array; break;
+ case event::string: t = json_type::string; break;
+ case event::number: t = (p.value ()[0] == '-'
+ ? json_type::signed_number
+ : json_type::unsigned_number); break;
+ case event::boolean: t = json_type::boolean; break;
+ case event::null: t = json_type::null; break;
+ case event::name:
+ case event::end_array:
+ case event::end_object:
+ {
+ assert (false);
+ type = json_type::null;
+ return;
+ }
+ }
+
+ if (et && *et != t)
+ {
+ throw invalid_json_input (
+ p.input_name != nullptr ? p.input_name : "",
+ p.line (),
+ p.column (),
+ p.position (),
+ string_type ("expected ") + to_string (*et) + " instead of " +
+ to_string (t));
+ }
+
+ switch (t)
+ {
+ case json_type::object:
+ {
+ object_type o; // For exception safety.
+ while (*p.next () != event::end_object)
+ {
+ string_type n (p.name ());
+
+ // Check for duplicates. For now we fail but in the future we may
+ // provide a mode (via a flag) to override instead.
+ //
+ if (find_if (o.begin (), o.end (),
+ [&n] (const json_member& m)
+ {
+ return m.name == n;
+ }) != o.end ())
+ {
+ throw invalid_json_input (
+ p.input_name != nullptr ? p.input_name : "",
+ p.line (),
+ p.column (),
+ p.position (),
+ "duplicate object member '" + n + '\'');
+ }
+
+ o.push_back (json_member {move (n), json_value (p)});
+ }
+
+ new (&object) object_type (move (o));
+ type = t;
+ break;
+ }
+ case json_type::array:
+ {
+ array_type c; // For exception safety.
+ while (*p.peek () != event::end_array)
+ c.push_back (json_value (p));
+ p.next (); // Consume end_array.
+
+ new (&array) array_type (move (c));
+ type = t;
+ break;
+ }
+ case json_type::string:
+ {
+ string_type& s (p.value ());
+
+ // Don't move if small string optimized.
+ //
+ if (s.size () > 15)
+ new (&string) string_type (move (s));
+ else
+ new (&string) string_type (s);
+
+ type = t;
+ break;
+ }
+ case json_type::signed_number:
+ {
+ signed_number = p.value<int64_t> ();
+ type = t;
+ break;
+ }
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ {
+ unsigned_number = p.value<uint64_t> ();
+ type = t;
+ break;
+ }
+ case json_type::boolean:
+ {
+ boolean = p.value<bool> ();
+ type = t;
+ break;
+ }
+ case json_type::null:
+ {
+ type = t;
+ break;
+ }
+ }
+ }
+
+ void json_value::
+ serialize (json_buffer_serializer& s, optional<json_type> et) const
+ {
+ using namespace butl::json;
+
+ if (et && *et != type)
+ {
+ throw invalid_json_output (
+ nullopt,
+ invalid_json_output::error_code::invalid_value,
+ string_type ("expected ") + to_string (*et) + " instead of " +
+ to_string (type));
+ }
+
+ switch (type)
+ {
+ case json_type::null:
+ {
+ s.value (nullptr);
+ break;
+ }
+ case json_type::boolean:
+ {
+ s.value (boolean);
+ break;
+ }
+ case json_type::signed_number:
+ {
+ s.value (signed_number);
+ break;
+ }
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ {
+ // When we have JSON5 support, we will be able to serialize
+ // hexadecimal properly.
+ //
+ s.value (unsigned_number);
+ break;
+ }
+ case json_type::string:
+ {
+ s.value (string);
+ break;
+ }
+ case json_type::array:
+ {
+ s.begin_array ();
+ for (const json_value& e: array)
+ e.serialize (s);
+ s.end_array ();
+ break;
+ }
+ case json_type::object:
+ {
+ s.begin_object ();
+ for (const json_member& m: object)
+ {
+ s.member_name (m.name);
+ m.value.serialize (s);
+ }
+ s.end_object ();
+ break;
+ }
+ }
+ }
+
+#else
+ json_value::
+ json_value (json_parser&, optional<json_type>)
+ {
+ assert (false);
+ type = json_type::null;
+ }
+
+ void json_value::
+ serialize (json_buffer_serializer&, optional<json_type>) const
+ {
+ assert (false);
+ }
+#endif
+}
diff --git a/libbuild2/json.hxx b/libbuild2/json.hxx
new file mode 100644
index 0000000..1f2694d
--- /dev/null
+++ b/libbuild2/json.hxx
@@ -0,0 +1,316 @@
+// file : libbuild2/json.hxx -*- C++ -*-
+// license : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUILD2_JSON_HXX
+#define LIBBUILD2_JSON_HXX
+
+#include <libbuild2/types.hxx>
+#include <libbuild2/utility.hxx>
+
+#include <libbuild2/export.hxx>
+
+namespace butl
+{
+ namespace json
+ {
+ enum class event: uint8_t;
+ class parser;
+ class buffer_serializer;
+ class stream_serializer;
+ class invalid_json_input;
+ class invalid_json_output;
+ }
+}
+
+namespace build2
+{
+ using json_event = butl::json::event;
+ using json_parser = butl::json::parser;
+ using json_buffer_serializer = butl::json::buffer_serializer;
+ using json_stream_serializer = butl::json::stream_serializer;
+ using butl::json::invalid_json_input;
+ using butl::json::invalid_json_output;
+
+#ifndef BUILD2_BOOTSTRAP
+ LIBBUILD2_SYMEXPORT const char*
+ to_string (json_event);
+#endif
+
+ // @@ TODO:
+ //
+ // - provide swap().
+ // - provide operator=(uint64_t), etc.
+ // - provide std::hash specialization
+ // - tighted at()/[] interface in json_array and json_object
+ // - tighten noexcep where possible
+ // - operator bool() - in a sense null is like nullopt.
+ //
+
+ // This JSON representation has one extensions compared to the standard JSON
+ // model: it distinguishes between signed, unsigned, and hexadecimal
+ // numbers.
+ //
+ // Note also that we don't assume that object members are in a sorted order
+ // (but do assume there are no duplicates). However, we could add an
+ // argument to signal that this is the case to speed up some functions, for
+ // example, compare().
+ //
+ enum class json_type: uint8_t
+ {
+ null, // Note: keep first for comparison.
+ boolean,
+ signed_number,
+ unsigned_number,
+ hexadecimal_number,
+ string,
+ array,
+ object,
+ };
+
+ // Return the JSON type as string. If distinguish_numbers is true, then
+ // distinguish between the singned, unsigned, and hexadecimal types.
+ //
+ LIBBUILD2_SYMEXPORT const char*
+ to_string (json_type, bool distinguish_numbers = false) noexcept;
+
+ inline ostream&
+ operator<< (ostream& os, json_type t) {return os << to_string (t);}
+
+ struct json_member;
+
+ class LIBBUILD2_SYMEXPORT json_value
+ {
+ public:
+ using string_type = build2::string;
+ using array_type = vector<json_value>;
+ using object_type = vector<json_member>;
+
+ json_type type;
+
+ union
+ {
+ bool boolean;
+ int64_t signed_number;
+ uint64_t unsigned_number; // Also used for hexadecimal_number.
+ string_type string;
+ array_type array;
+ object_type object;
+ };
+
+ explicit
+ json_value (json_type = json_type::null) noexcept;
+
+ explicit
+ json_value (std::nullptr_t) noexcept;
+
+ explicit
+ json_value (bool) noexcept;
+
+ explicit
+ json_value (int64_t) noexcept;
+
+ explicit
+ json_value (uint64_t, bool hexadecimal = false) noexcept;
+
+ explicit
+ json_value (string_type);
+
+ // If the expected type is specfied, then fail if it does not match
+ // parsed. Throws invalid_json_input.
+ //
+ explicit
+ json_value (json_parser&, optional<json_type> expected = {});
+
+ // If the expected type is specfied, then fail if it does not match the
+ // value's. Throws invalid_json_output.
+ //
+ void
+ serialize (json_buffer_serializer&,
+ optional<json_type> expected = {}) const;
+
+ // Note that values of different types are never equal, except for
+ // signed/unsigned/hexadecimal numbers. Null is equal to null and is less
+ // than any other value. Arrays are compared lexicographically. Object
+ // members are considered in the lexicographically-compared name-ascending
+ // order (see RFC8785). An absent member is less than a present member
+ // (even if it's null).
+ //
+ int
+ compare (const json_value&) const noexcept;
+
+ // Append/prepend one JSON value to another. Throw invalid_argument if the
+ // values are incompatible. Note that for numbers this can also lead to
+ // the change of the value type.
+ //
+ // Append/prepend to an object overrides existing members. Append/prepend
+ // an array to an array splices in the array elements rather than adding
+ // an element of the array type.
+ //
+ void
+ append (json_value&&);
+
+ void
+ prepend (json_value&&);
+
+
+ // Array element access.
+ //
+ // If the index is out of array bounds, the at() functions throw
+ // std::out_of_range, the const operator[] returns null_json_value, and
+ // the non-const operator[] inserts a new null value at the specified
+ // position (filling any missing elements in between with nulls) and
+ // returns that. All three functions throw std::invalid_argument if the
+ // value is not an array or null with null treated as (missing) array
+ // rather than wrong value type (and with at() functons throwing
+ // out_of_range in this case).
+ //
+ // Note that non-const operator[] will not only insert a new element but
+ // will also turn the value it is called upon into array if it is null.
+ // This semantics allows you to string several subscripts to build up a
+ // chain of values.
+ //
+ // Note also that while the operator[] interface is convenient for
+ // accessing and modifying (or building up) values deep in the tree, it
+ // can lead to inefficiencies or even undesirable semantics during
+ // otherwise read-only access of a non-const object due to the potential
+ // insertion of null values for missing array elements. As a result, it's
+ // recommended to alwas use a const reference for read-only access (or use
+ // the at() interface if this is deemed too easy to forget).
+ //
+ const json_value&
+ at (size_t) const;
+
+ json_value&
+ at (size_t);
+
+ const json_value&
+ operator[] (size_t) const;
+
+ json_value&
+ operator[] (size_t);
+
+
+ // Object member access.
+ //
+ // If a member with the specified name is not found in the object, the
+ // at() functions throw std::out_of_range, the const operator[] returns
+ // null_json_value, and the non-const operator[] adds a new member with
+ // the specified name and null value and returns that value. All three
+ // functions throw std::invalid_argument if the value is not an array or
+ // null with null treated as (missing) object rather than wrong value type
+ // (and with at() functons throwing out_of_range in this case).
+ //
+ // Note that non-const operator[] will not only insert a new member but
+ // will also turn the value it is called upon into object if it is null.
+ // This semantics allows you to string several subscripts to build up a
+ // chain of values.
+ //
+ // Note also that while the operator[] interface is convenient for
+ // accessing and modifying (or building up) values deep in the tree, it
+ // can lead to inefficiencies or even undesirable semantics during
+ // otherwise read-only access of a non-const object due to the potential
+ // insertion of null values for missing object members. As a result, it's
+ // recommended to alwas use a const reference for read-only access (or use
+ // the at() interface if this is deemed too easy to forget).
+ //
+ const json_value&
+ at (const char*) const;
+
+ json_value&
+ at (const char*);
+
+ const json_value&
+ operator[] (const char*) const;
+
+ json_value&
+ operator[] (const char*);
+
+ const json_value&
+ at (const string_type&) const;
+
+ json_value&
+ at (const string_type&);
+
+ const json_value&
+ operator[] (const string_type&) const;
+
+ json_value&
+ operator[] (const string_type&);
+
+ // Note that the moved-from value becomes JSON null value.
+ //
+ json_value (json_value&&) noexcept;
+ json_value (const json_value&);
+
+ json_value& operator= (json_value&&) noexcept;
+ json_value& operator= (const json_value&);
+
+ ~json_value () noexcept;
+ };
+
+ LIBBUILD2_SYMEXPORT extern const json_value null_json_value;
+
+ inline bool
+ operator== (const json_value& x, const json_value& y) {return x.compare (y) == 0;}
+
+ inline bool
+ operator!= (const json_value& x, const json_value& y) {return !(x == y);}
+
+ inline bool
+ operator< (const json_value& x, const json_value& y) {return x.compare (y) < 0;}
+
+ inline bool
+ operator<= (const json_value& x, const json_value& y) {return x.compare (y) <= 0;}
+
+ inline bool
+ operator> (const json_value& x, const json_value& y) {return !(x <= y);}
+
+ inline bool
+ operator>= (const json_value& x, const json_value& y) {return !(x < y);}
+
+ // A JSON object member.
+ //
+ struct json_member
+ {
+ // @@ TODO: add some convenience constructors?
+
+ string name;
+ json_value value;
+ };
+
+ // A JSON value that can only be an array.
+ //
+ class /*LIBBUILD2_SYMEXPORT*/ json_array: public json_value
+ {
+ public:
+ // Create empty array.
+ //
+ json_array () noexcept;
+
+ explicit
+ json_array (json_parser&);
+
+ void
+ serialize (json_buffer_serializer& s) const;
+ };
+
+ // A JSON value that can only be an object.
+ //
+ class /*LIBBUILD2_SYMEXPORT*/ json_object: public json_value
+ {
+ public:
+ // Create empty object.
+ //
+ json_object () noexcept;
+
+ explicit
+ json_object (json_parser&);
+
+ void
+ serialize (json_buffer_serializer& s) const;
+ };
+}
+
+#include <libbuild2/json.ixx>
+
+#endif // LIBBUILD2_JSON_HXX
diff --git a/libbuild2/json.ixx b/libbuild2/json.ixx
new file mode 100644
index 0000000..c2b8845
--- /dev/null
+++ b/libbuild2/json.ixx
@@ -0,0 +1,222 @@
+// file : libbuild2/json.ixx -*- C++ -*-
+// license : MIT; see accompanying LICENSE file
+
+namespace build2
+{
+ inline json_value::
+ ~json_value () noexcept
+ {
+ switch (type)
+ {
+ case json_type::null:
+ case json_type::boolean:
+ case json_type::signed_number:
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number: break;
+ case json_type::string: string.~string_type (); break;
+ case json_type::array: array.~array_type (); break;
+ case json_type::object: object.~object_type (); break;
+ }
+ }
+
+ inline json_value::
+ json_value (json_type t) noexcept
+ : type (t)
+ {
+ switch (type)
+ {
+ case json_type::null: break;
+ case json_type::boolean: boolean = false; break;
+ case json_type::signed_number: signed_number = 0; break;
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number: unsigned_number = 0; break;
+ case json_type::string: new (&string) string_type (); break;
+ case json_type::array: new (&array) array_type (); break;
+ case json_type::object: new (&object) object_type (); break;
+ }
+ }
+
+ inline json_value::
+ json_value (std::nullptr_t) noexcept
+ : type (json_type::null)
+ {
+ }
+
+ inline json_value::
+ json_value (bool v) noexcept
+ : type (json_type::boolean), boolean (v)
+ {
+ }
+
+ inline json_value::
+ json_value (int64_t v) noexcept
+ : type (json_type::signed_number), signed_number (v)
+ {
+ }
+
+ inline json_value::
+ json_value (uint64_t v, bool hex) noexcept
+ : type (hex
+ ? json_type::hexadecimal_number
+ : json_type::unsigned_number),
+ unsigned_number (v)
+ {
+ }
+
+ inline json_value::
+ json_value (string_type v)
+ : type (json_type::string), string (move (v))
+ {
+ }
+
+ inline const json_value& json_value::
+ at (const string_type& n) const
+ {
+ return at (n.c_str ());
+ }
+
+ inline json_value& json_value::
+ at (const string_type& n)
+ {
+ return at (n.c_str ());
+ }
+
+ inline const json_value& json_value::
+ operator[] (const string_type& n) const
+ {
+ return operator[] (n.c_str ());
+ }
+
+ inline json_value& json_value::
+ operator[] (const string_type& n)
+ {
+ return operator[] (n.c_str ());
+ }
+
+ inline json_value::
+ json_value (json_value&& v) noexcept
+ : type (v.type)
+ {
+ switch (type)
+ {
+ case json_type::null:
+ break;
+ case json_type::boolean:
+ boolean = v.boolean;
+ break;
+ case json_type::signed_number:
+ signed_number = v.signed_number;
+ break;
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ unsigned_number = v.unsigned_number;
+ break;
+ case json_type::string:
+ new (&string) string_type (move (v.string));
+ v.string.~string_type ();
+ break;
+ case json_type::array:
+ new (&array) array_type (move (v.array));
+ v.array.~array_type ();
+ break;
+ case json_type::object:
+ new (&object) object_type (move (v.object));
+ v.object.~object_type ();
+ break;
+ }
+
+ v.type = json_type::null;
+ }
+
+ inline json_value::
+ json_value (const json_value& v)
+ : type (v.type)
+ {
+ switch (type)
+ {
+ case json_type::null:
+ break;
+ case json_type::boolean:
+ boolean = v.boolean;
+ break;
+ case json_type::signed_number:
+ signed_number = v.signed_number;
+ break;
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ unsigned_number = v.unsigned_number;
+ break;
+ case json_type::string:
+ new (&string) string_type (v.string);
+ break;
+ case json_type::array:
+ new (&array) array_type (v.array);
+ break;
+ case json_type::object:
+ new (&object) object_type (v.object);
+ break;
+ }
+ }
+
+ inline json_value& json_value::
+ operator= (json_value&& v) noexcept
+ {
+ if (this != &v)
+ {
+ this->~json_value ();
+ new (this) json_value (move (v));
+ }
+ return *this;
+ }
+
+ inline json_value& json_value::
+ operator= (const json_value& v)
+ {
+ if (this != &v)
+ {
+ this->~json_value ();
+ new (this) json_value (v);
+ }
+ return *this;
+ }
+
+ // json_array
+ //
+ inline json_array::
+ json_array () noexcept
+ : json_value (json_type::array)
+ {
+ }
+
+ inline json_array::
+ json_array (json_parser& p)
+ : json_value (p, json_type::array)
+ {
+ }
+
+ inline void json_array::
+ serialize (json_buffer_serializer& s) const
+ {
+ json_value::serialize (s, json_type::array);
+ }
+
+ // json_object
+ //
+ inline json_object::
+ json_object () noexcept
+ : json_value (json_type::object)
+ {
+ }
+
+ inline json_object::
+ json_object (json_parser& p)
+ : json_value (p, json_type::object)
+ {
+ }
+
+ inline void json_object::
+ serialize (json_buffer_serializer& s) const
+ {
+ json_value::serialize (s, json_type::object);
+ }
+}
diff --git a/libbuild2/parser.cxx b/libbuild2/parser.cxx
index 043cd10..1ac159b 100644
--- a/libbuild2/parser.cxx
+++ b/libbuild2/parser.cxx
@@ -5761,30 +5761,106 @@ namespace build2
const value_type* parser::
find_value_type (const scope*, const string& n)
{
- auto ptr = [] (const value_type& vt) {return &vt;};
-
- return
- n == "bool" ? ptr (value_traits<bool>::value_type) :
- n == "int64" ? ptr (value_traits<int64_t>::value_type) :
- n == "uint64" ? ptr (value_traits<uint64_t>::value_type) :
- n == "string" ? ptr (value_traits<string>::value_type) :
- n == "path" ? ptr (value_traits<path>::value_type) :
- n == "dir_path" ? ptr (value_traits<dir_path>::value_type) :
- n == "abs_dir_path" ? ptr (value_traits<abs_dir_path>::value_type) :
- n == "name" ? ptr (value_traits<name>::value_type) :
- n == "name_pair" ? ptr (value_traits<name_pair>::value_type) :
- n == "target_triplet" ? ptr (value_traits<target_triplet>::value_type) :
- n == "project_name" ? ptr (value_traits<project_name>::value_type) :
-
- n == "int64s" ? ptr (value_traits<int64s>::value_type) :
- n == "uint64s" ? ptr (value_traits<uint64s>::value_type) :
- n == "strings" ? ptr (value_traits<strings>::value_type) :
- n == "paths" ? ptr (value_traits<paths>::value_type) :
- n == "dir_paths" ? ptr (value_traits<dir_paths>::value_type) :
- n == "names" ? ptr (value_traits<vector<name>>::value_type) :
- n == "cmdline" ? ptr (value_traits<cmdline>::value_type) :
-
- nullptr;
+ switch (n[0])
+ {
+ case 'a':
+ {
+ if (n == "abs_dir_path") return &value_traits<abs_dir_path>::value_type;
+ break;
+ }
+ case 'b':
+ {
+ if (n == "bool") return &value_traits<bool>::value_type;
+ break;
+ }
+ case 'c':
+ {
+ if (n == "cmdline") return &value_traits<cmdline>::value_type;
+ break;
+ }
+ case 'd':
+ {
+ if (n.compare (0, 8, "dir_path") == 0)
+ {
+ if (n[8] == '\0') return &value_traits<dir_path>::value_type;
+ if (n[8] == 's' &&
+ n[9] == '\0') return &value_traits<dir_paths>::value_type;
+ }
+ break;
+ }
+ case 'i':
+ {
+ if (n.compare (0, 5, "int64") == 0)
+ {
+ if (n[5] == '\0') return &value_traits<int64_t>::value_type;
+ if (n[5] == 's' &&
+ n[6] == '\0') return &value_traits<int64s>::value_type;
+ }
+ break;
+ }
+ case 'j':
+ {
+ if (n.compare (0, 4, "json") == 0)
+ {
+ if (n[4] == '\0') return &value_traits<json_value>::value_type;
+ if (n == "json_array") return &value_traits<json_array>::value_type;
+ if (n == "json_object") return &value_traits<json_object>::value_type;
+ }
+ break;
+ }
+ case 'n':
+ {
+ if (n.compare (0, 4, "name") == 0)
+ {
+ if (n[4] == '\0') return &value_traits<name>::value_type;
+ if (n[4] == 's' &&
+ n[5] == '\0') return &value_traits<vector<name>>::value_type;
+ if (n == "name_pair") return &value_traits<name_pair>::value_type;
+ }
+ break;
+ }
+
+ case 'p':
+ {
+ if (n.compare (0, 4, "path") == 0)
+ {
+ if (n[4] == '\0') return &value_traits<path>::value_type;
+ if (n[4] == 's' &&
+ n[5] == '\0') return &value_traits<paths>::value_type;
+ }
+ else if (n == "project_name") return &value_traits<project_name>::value_type;
+ break;
+ }
+ case 's':
+ {
+ if (n.compare (0, 6, "string") == 0)
+ {
+ if (n[6] == '\0') return &value_traits<string>::value_type;
+ if (n[6] == 's' &&
+ n[7] == '\0') return &value_traits<strings>::value_type;
+ }
+ break;
+ }
+ case 't':
+ {
+ if (n == "target_triplet") return &value_traits<target_triplet>::value_type;
+ break;
+ }
+ case 'u':
+ {
+ if (n.compare (0, 6, "uint64") == 0)
+ {
+ if (n[6] == '\0') return &value_traits<uint64_t>::value_type;
+ if (n[6] == 's' &&
+ n[7] == '\0') return &value_traits<uint64s>::value_type;
+ }
+ break;
+ }
+ default:
+ break;
+ }
+
+ return nullptr;
}
void parser::
diff --git a/libbuild2/variable.cxx b/libbuild2/variable.cxx
index 0ad63b1..b0fe32a 100644
--- a/libbuild2/variable.cxx
+++ b/libbuild2/variable.cxx
@@ -3,10 +3,16 @@
#include <libbuild2/variable.hxx>
+#include <cstdio> // snprintf()
#include <cstring> // memcmp(), memcpy()
#include <libbutl/path-pattern.hxx>
+#ifndef BUILD2_BOOTSTRAP
+# include <libbutl/json/parser.hxx>
+# include <libbutl/json/serializer.hxx>
+#endif
+
#include <libbuild2/target.hxx>
#include <libbuild2/diagnostics.hxx>
@@ -584,6 +590,8 @@ namespace build2
if (!wspace (v[0]))
{
+ // Note: see also similar code in to_json_value().
+ //
int b (v[0] == '0' && (v[1] == 'x' || v[1] == 'X') ? 16 : 10);
// May throw invalid_argument or out_of_range.
@@ -1501,6 +1509,924 @@ namespace build2
nullptr // Iterate.
};
+ // json
+ //
+ static string
+ to_string_value (name& n, const char* what)
+ {
+ if (n.typed () || n.qualified () || n.pattern)
+ throw_invalid_argument (n, nullptr, what);
+
+ string s;
+
+ if (n.simple ())
+ s.swap (n.value);
+ else
+ {
+ // Note that here we cannot assume what's in dir is really a path (think
+ // s/foo/bar/) so we have to reverse it exactly.
+ //
+ s = move (n.dir).representation (); // Move out of path.
+
+ if (!n.value.empty ())
+ s += n.value; // Separator is already there.
+ }
+
+ return s;
+ }
+
+ static json_value
+ to_json_value (name& n, const char* what)
+ {
+ if (n.typed () || n.qualified () || n.pattern)
+ throw_invalid_argument (n, nullptr, what);
+
+ string s;
+
+ if (n.simple ())
+ s.swap (n.value);
+ else
+ {
+ // Note that here we cannot assume what's in dir is really a path (think
+ // s/foo/bar/) so we have to reverse it exactly.
+ //
+ s = move (n.dir).representation (); // Move out of path.
+
+ if (!n.value.empty ())
+ s += n.value; // Separator is already there.
+
+ // A path is always interpreted as a JSON string.
+ //
+ return json_value (move (s));
+ }
+
+ bool f;
+ if (s.empty ())
+ return json_value (string ());
+ if (s == "null")
+ return json_value ();
+ else if ((f = (s == "true")) || s == "false")
+ return json_value (f);
+ else if (s.find_first_not_of (
+ "0123456789", (f = (s[0] == '-')) ? 1 : 0) == string::npos)
+ {
+ name n (move (s));
+ return f
+ ? json_value (value_traits<int64_t>::convert (n, nullptr))
+ : json_value (value_traits<uint64_t>::convert (n, nullptr));
+ }
+ //
+ // Handle the hex notation similar to <uint64_t>::convert() (and JSON5).
+ //
+ else if (s[0] == '0' &&
+ (s[1] == 'x' || s[1] == 'X') &&
+ s.size () > 2 &&
+ s.find_first_not_of ("0123456789aAbBcCdDeEfF", 2) == string::npos)
+ {
+ return json_value (
+ value_traits<uint64_t>::convert (name (move (s)), nullptr),
+ true /* hex */);
+ }
+ else
+ {
+ // If this is not a JSON representation of string, array, or object,
+ // then treat it as a string.
+ //
+ // Note that the special `"`, `{`, and `[` characters could be preceded
+ // with whitespaces. Note: see similar test in json_object below.
+ //
+ size_t p (s.find_first_not_of (" \t\n\r"));
+
+ if (p == string::npos || (s[p] != '"' && s[p] != '{' && s[p] != '['))
+ return json_value (move (s));
+
+ // Parse as valid JSON input text.
+ //
+#ifndef BUILD2_BOOTSTRAP
+ try
+ {
+ json_parser p (s, nullptr /* name */);
+ return json_value (p);
+ }
+ catch (const invalid_json_input& e)
+ {
+ // Turned out printing line/column/offset can be misleading since we
+ // could be parsing a single name from a potential list of names.
+ // feels like without also printing the value this is of not much use.
+ //
+#if 0
+ string m ("invalid json input at line ");
+ m += to_string (e.line);
+ m += ", column ";
+ m += to_string (e.column);
+ m += ", byte offset ";
+ m += to_string (e.position);
+ m += ": ";
+ m += e.what ();
+#else
+ string m ("invalid json input: ");
+ m += e.what ();
+#endif
+ throw invalid_argument (move (m));
+ }
+#else
+ throw invalid_argument ("json parsing requested during bootstrap");
+#endif
+ }
+ }
+
+ json_value value_traits<json_value>::
+ convert (names&& ns)
+ {
+ size_t n (ns.size ());
+
+ if (n == 0)
+ {
+ // Note: this is the ([json] ) case, not ([json] ""). See also the
+ // relevant note in json_reverse() below.
+ //
+ return json_value (); // null
+ }
+ else if (n == 1)
+ {
+ return to_json_value (ns.front (), "json");
+ }
+ else
+ {
+ if (ns.front ().pair) // object
+ {
+ json_value r (json_type::object);
+ r.object.reserve (n / 2);
+
+ for (auto i (ns.begin ()); i != ns.end (); ++i)
+ {
+ if (!i->pair)
+ throw invalid_argument (
+ "expected pair in json member value '" + to_string (*i) + '\'');
+
+ // Note that we could support JSON-quoted member names but it's
+ // unclear why would someone want that (and if they do, they can
+ // always specify JSON text instead).
+ //
+ // @@ The empty pair value ([json] one@ ) which is currently empty
+ // string is inconsistent with empty value ([json] ) above which
+ // is null. Maybe we could distinguish the one@ and one@"" cases
+ // via type hints?
+ //
+ string n (to_string_value (*i, "json member name"));
+ json_value v (to_json_value (*++i, "json member"));
+
+ // Check for duplicates. One can use append/prepend to merge.
+ //
+ if (find_if (r.object.begin (), r.object.end (),
+ [&n] (const json_member& m)
+ {
+ return m.name == n;
+ }) != r.object.end ())
+ {
+ throw invalid_argument (
+ "duplicate json object member '" + n + '\'');
+ }
+
+ r.object.push_back (json_member {move (n), move (v)});
+ }
+
+ return r;
+ }
+ else // array
+ {
+ json_value r (json_type::array);
+ r.array.reserve (n);
+
+ for (name& n: ns)
+ {
+ if (n.pair)
+ throw invalid_argument (
+ "unexpected pair in json array element value '" +
+ to_string (n) + '\'');
+
+ r.array.push_back (to_json_value (n, "json array element"));
+ }
+
+ return r;
+ }
+ }
+ }
+
+ static void
+ json_assign (value& v, names&& ns, const variable* var)
+ {
+ using traits = value_traits<json_value>;
+
+ try
+ {
+ traits::assign (v, traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json value";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ static void
+ json_append (value& v, names&& ns, const variable* var)
+ {
+ using traits = value_traits<json_value>;
+
+ try
+ {
+ traits::append (v, traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json value";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ static void
+ json_prepend (value& v, names&& ns, const variable* var)
+ {
+ using traits = value_traits<json_value>;
+
+ try
+ {
+ traits::prepend (v, traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json value";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ static names_view
+ json_reverse (const value& x, names& ns, bool)
+ {
+ const json_value& v (x.as<json_value> ());
+
+ switch (v.type)
+ {
+ case json_type::null:
+ {
+ // @@ Hm, it would be nice if this somehow got mapped to [null]/empty
+ // but still be round-trippable to JSON null. Perhaps via type
+ // hint?
+ //
+ // But won't `print ([json] null)` printing nothing be
+ // surprising. Also, it's not clear that mapping JSON null to out
+ // [null] is a good idea since our [null] means "no value" while
+ // JSON null means "null value".
+ //
+ // Maybe the current semantics is the best: we map our [null] and
+ // empty names to JSON null (naturally) but we always reverse JSON
+ // null to the JSON "null" literal. Or maybe we could reverse it to
+ // null but type-hint it that it's a spelling or [null]/empty.
+ // Quite fuzzy, admittedly. In our model null values decay to empty
+ // so JSON null decaying to "null" literal is strange. Let's try
+ // and see how it goes. See also json_subscript_impl() below.
+ //
+#if 0
+ ns.push_back (name ("null"));
+#endif
+ break;
+ }
+ case json_type::boolean:
+ {
+ ns.push_back (name (v.boolean ? "true" : "false"));
+ break;
+ }
+ case json_type::signed_number:
+ {
+ ns.push_back (value_traits<int64_t>::reverse (v.signed_number));
+ break;
+ }
+ case json_type::unsigned_number:
+ {
+ ns.push_back (value_traits<uint64_t>::reverse (v.unsigned_number));
+ break;
+ }
+ case json_type::hexadecimal_number:
+ {
+ // Hexadecimal representation of 64-bit integers requires a maximum of
+ // 10 character (plus '\0'): 0xffffffff.
+ //
+ char buf[11];
+ snprintf (buf, sizeof (buf),
+ "0x%llx",
+ static_cast<unsigned long long> (v.unsigned_number));
+
+ ns.push_back (name (string (buf)));
+ break;
+ }
+ case json_type::string:
+ //
+ // @@ Hm, it would be nice if this somehow got mapped to unquoted
+ // string but still be round-trippable to JSON value. Perhaps via
+ // the type hint idea? This is pretty bad. See also subscript we
+ // hacked around this somewhat.
+ //
+ // Note that it may be tempting to fix this by only quoting strings
+ // that would otherwise be mis-interpreted (null, true, all digits,
+ // etc). But that would be worse: things would seem to work but
+ // fall apart in the perhaps unlikely event of encountering one of
+ // the problematic values. It is better to produce a consistent
+ // result.
+ //
+ case json_type::array:
+ case json_type::object:
+ {
+ // Serialize as JSON output text.
+ //
+ string o;
+
+#ifndef BUILD2_BOOTSTRAP
+ try
+ {
+ // Disable pretty-printing so that the output is all on the same
+ // line. While it's not going to be easy to read for larger JSON
+ // outputs, it will fit better into the existing model where none of
+ // the value representations use formatting newlines. If a pretty-
+ // printed representation is required, then the $json.serialize()
+ // function can be used to obtain it.
+ //
+ json_buffer_serializer s (o, 0 /* indentation */);
+ v.serialize (s);
+ }
+ catch (const invalid_json_output& e)
+ {
+ // Note: the same diagnostics as in $json.serialize().
+ //
+ diag_record dr;
+ dr << fail << "invalid json value: " << e;
+
+ if (e.event)
+ dr << info << "while serializing " << to_string (*e.event);
+
+ if (e.offset != string::npos)
+ dr << info << "offending byte offset " << e.offset;
+ }
+#else
+ fail << "json serialization requested during bootstrap";
+#endif
+ ns.push_back (name (move (o)));
+ break;
+ }
+ }
+
+ return ns;
+ }
+
+ static int
+ json_compare (const value& l, const value& r)
+ {
+ return l.as<json_value> ().compare (r.as<json_value> ());
+ }
+
+ // Return null value if the index/name is out of range.
+ //
+ static value
+ json_subscript_impl (const value& val, value* val_data,
+ uint64_t i, const string& n, bool index)
+ {
+ const json_value& jv (val.as<json_value> ());
+
+ json_value jr;
+
+ if (index)
+ {
+ if (i >= (jv.type == json_type::array ? jv.array.size () :
+ jv.type == json_type::object ? jv.object.size () : 1))
+ return value ();
+
+ switch (jv.type)
+ {
+ case json_type::null:
+ return value (); // JSON null has no elements.
+ case json_type::boolean:
+ case json_type::signed_number:
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ case json_type::string:
+ {
+ // Steal the value if possible.
+ //
+ jr = (&val == val_data
+ ? json_value (move (const_cast<json_value&> (jv)))
+ : json_value (jv));
+ break;
+ }
+ case json_type::array:
+ {
+ // Steal the value if possible.
+ //
+ const json_value& r (jv.array[i]);
+ jr = (&val == val_data
+ ? json_value (move (const_cast<json_value&> (r)))
+ : json_value (r));
+ break;
+ }
+ case json_type::object:
+ {
+ // Represent as an object with one member.
+ //
+ new (&jr.object) json_value::object_type ();
+ jr.type = json_type::object;
+
+ // Steal the member if possible.
+ //
+ const json_member& m (jv.object[i]);
+ jr.object.push_back (&val == val_data
+ ? json_member (move (const_cast<json_member&> (m)))
+ : json_member (m));
+ break;
+ }
+ }
+ }
+ else
+ {
+ auto i (find_if (jv.object.begin (),
+ jv.object.end (),
+ [&n] (const json_member& m)
+ {
+ return m.name == n;
+ }));
+
+ if (i == jv.object.end ())
+ return value ();
+
+ // Steal the member value if possible.
+ //
+ jr = (&val == val_data
+ ? json_value (move (const_cast<json_value&> (i->value)))
+ : json_value (i->value));
+ }
+
+ // @@ As a temporary work around for the lack of type hints (see
+ // json_reverse() for background), reverse simple JSON values to the
+ // corresponding fundamental type values. The thinking here is that
+ // subscript (and iteration) is primarily meant for consumption (as
+ // opposed to reverse() where it is used to build up values and thus
+ // needs things to be fully reversible). Once we add type hints, then
+ // this should become unnecessary and we should be able to just always
+ // return json_value.
+ //
+ // @@ TODO: split this function into two (index/name) once get rid of this.
+ //
+#if 1
+ switch (jr.type)
+ {
+ case json_type::null: return value (names {});
+ case json_type::boolean: return value (jr.boolean);
+ case json_type::signed_number: return value (jr.signed_number);
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number: return value (jr.unsigned_number);
+ case json_type::string: return value (move (jr.string));
+ case json_type::array:
+ case json_type::object: break;
+ }
+#endif
+
+ return value (move (jr));
+ }
+
+ static value
+ json_subscript (const value& val, value* val_data,
+ value&& sub,
+ const location& sloc,
+ const location& bloc)
+ {
+ const json_value* jv (val.null ? nullptr : &val.as<json_value> ());
+
+ // For consistency with other places treat JSON null value as maybe
+ // missing array/object. In particular, we don't want to fail trying to
+ // lookup by-name on a null value which could have been an object.
+ //
+ if (jv != nullptr && jv->type == json_type::null)
+ jv = nullptr;
+
+ // Process subscript even if the value is null to make sure it is valid.
+ //
+ bool index;
+ uint64_t i (0);
+ string n;
+
+ // Always interpret uint64-typed subscript as index even for objects.
+ // This can be used to, for example, to iterate with an index over object
+ // members.
+ //
+ if (!sub.null && sub.type == &value_traits<uint64_t>::value_type)
+ {
+ i = sub.as<uint64_t> ();
+ index = true;
+ }
+ else
+ {
+ // How we interpret the subscript depends on the JSON value type. For
+ // objects we treat it as a string (member name) and for everything else
+ // as an index.
+ //
+ // What if the value is null and we don't have a JSON type? In this case
+ // we treat as a string since a valid number is also a valid string.
+ //
+ try
+ {
+ if (jv == nullptr || jv->type == json_type::object)
+ {
+ n = convert<string> (move (sub));
+ index = false;
+ }
+ else
+ {
+ i = convert<uint64_t> (move (sub));
+ index = true;
+ }
+ }
+ catch (const invalid_argument& e)
+ {
+ // We will likely be trying to interpret a member name as an integer
+ // due to the incorrect value type so issue appropriate diagnostics.
+ //
+ diag_record dr;
+ dr << fail (sloc) << "invalid json value subscript: " << e;
+
+ if (jv != nullptr && jv->type != json_type::object)
+ dr << info << "json value type is " << jv->type;
+
+ dr << info (bloc) << "use the '\\[' escape sequence if this is a "
+ << "wildcard pattern" << endf;
+ }
+ }
+
+ return (jv != nullptr
+ ? json_subscript_impl (val, val_data, i, n, index)
+ : value ());
+ }
+
+ void json_iterate (const value& val,
+ const function<void (value&&, bool first)>& f)
+ {
+ // Implement in terms of subscript for consistency (in particular,
+ // iterating over simple values like number, string).
+ //
+ for (uint64_t i (0);; ++i)
+ {
+ value e (json_subscript_impl (val, nullptr, i, {}, true));
+
+ if (e.null)
+ break;
+
+ f (move (e), i == 0);
+ }
+ }
+
+ const json_value value_traits<json_value>::empty_instance;
+ const char* const value_traits<json_value>::type_name = "json";
+
+ // Note that whether the json value is a container or not depends on its
+ // payload type. However, for our purposes it feels correct to assume it is
+ // a container rather than not with itself as the element type (see
+ // value_traits::{container, element_type} usage for details).
+ //
+ const value_type value_traits<json_value>::value_type
+ {
+ type_name,
+ sizeof (json_value),
+ nullptr, // No base.
+ true, // Container.
+ &value_traits<json_value>::value_type, // Element (itself).
+ &default_dtor<json_value>,
+ &default_copy_ctor<json_value>,
+ &default_copy_assign<json_value>,
+ &json_assign,
+ json_append,
+ json_prepend,
+ &json_reverse,
+ nullptr, // No cast (cast data_ directly).
+ &json_compare,
+ &default_empty<json_value>,
+ &json_subscript,
+ &json_iterate
+ };
+
+ // json_array
+ //
+ json_array value_traits<json_array>::
+ convert (names&& ns)
+ {
+ json_array r;
+
+ size_t n (ns.size ());
+ if (n == 0)
+ ; // Empty.
+ else if (n == 1)
+ {
+ // Tricky: this can still be JSON input text that is an array. And if
+ // it's not, then make it an element of an array.
+ //
+ json_value v (to_json_value (ns.front (), "json"));
+
+ if (v.type == json_type::array)
+ r.array = move (v.array);
+ else
+ r.array.push_back (move (v));
+ }
+ else
+ {
+ r.array.reserve (n);
+
+ for (name& n: ns)
+ {
+ if (n.pair)
+ throw invalid_argument (
+ "unexpected pair in json array element value '" +
+ to_string (n) + '\'');
+
+ r.array.push_back (to_json_value (n, "json array element"));
+ }
+ }
+
+ return r;
+ }
+
+ static void
+ json_array_assign (value& v, names&& ns, const variable* var)
+ {
+ using traits = value_traits<json_array>;
+
+ try
+ {
+ traits::assign (v, traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json array";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ static void
+ json_array_append (value& v, names&& ns, const variable* var)
+ {
+ using val_traits = value_traits<json_value>;
+ using arr_traits = value_traits<json_array>;
+
+ try
+ {
+ arr_traits::append (v, val_traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json array";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ static void
+ json_array_prepend (value& v, names&& ns, const variable* var)
+ {
+ using val_traits = value_traits<json_value>;
+ using arr_traits = value_traits<json_array>;
+
+ try
+ {
+ arr_traits::prepend (v, val_traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json array";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ const json_array value_traits<json_array>::empty_instance;
+ const char* const value_traits<json_array>::type_name = "json_array";
+
+ const value_type value_traits<json_array>::value_type
+ {
+ type_name,
+ sizeof (json_array),
+ &value_traits<json_value>::value_type, // Base (assuming direct cast works
+ // for both).
+ true, // Container.
+ &value_traits<json_value>::value_type, // Element (json_value).
+ &default_dtor<json_array>,
+ &default_copy_ctor<json_array>,
+ &default_copy_assign<json_array>,
+ &json_array_assign,
+ &json_array_append,
+ &json_array_prepend,
+ &json_reverse,
+ nullptr, // No cast (cast data_ directly).
+ &json_compare,
+ &default_empty<json_array>,
+ &json_subscript,
+ &json_iterate
+ };
+
+ // json_object
+ //
+ json_object value_traits<json_object>::
+ convert (names&& ns)
+ {
+ json_object r;
+
+ size_t n (ns.size ());
+ if (n == 0)
+ ; // Empty.
+ else if (n == 1)
+ {
+ // Tricky: this can still be JSON input text that is an object. So do
+ // a similar check as in to_json_value() above.
+ //
+ name& n (ns.front ());
+
+ if (!n.simple () || n.pattern)
+ throw_invalid_argument (n, nullptr, "json object");
+
+ string& s (n.value);
+ size_t p (s.find_first_not_of (" \t\n\r"));
+
+ if (p == string::npos || s[p] != '{')
+ {
+ // Unlike for array above, we cannot turn any value into a member.
+ //
+ throw invalid_argument ("expected json object instead of '" + s + '\'');
+ }
+
+ json_value v (to_json_value (ns.front (), "json object"));
+ assert (v.type == json_type::object);
+ r.object = move (v.object);
+ }
+ else
+ {
+ r.object.reserve (n / 2);
+
+ for (auto i (ns.begin ()); i != ns.end (); ++i)
+ {
+ if (!i->pair)
+ throw invalid_argument (
+ "expected pair in json member value '" + to_string (*i) + '\'');
+
+ string n (to_string_value (*i, "json member name"));
+ json_value v (to_json_value (*++i, "json member"));
+
+ if (find_if (r.object.begin (), r.object.end (),
+ [&n] (const json_member& m)
+ {
+ return m.name == n;
+ }) != r.object.end ())
+ {
+ throw invalid_argument (
+ "duplicate json object member '" + n + '\'');
+ }
+
+ r.object.push_back (json_member {move (n), move (v)});
+ }
+ }
+
+ return r;
+ }
+
+ static void
+ json_object_assign (value& v, names&& ns, const variable* var)
+ {
+ using traits = value_traits<json_object>;
+
+ try
+ {
+ traits::assign (v, traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json object";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ static void
+ json_object_append (value& v, names&& ns, const variable* var)
+ {
+ using val_traits = value_traits<json_value>;
+ using obj_traits = value_traits<json_object>;
+
+ try
+ {
+ obj_traits::append (v, val_traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json object";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ static void
+ json_object_prepend (value& v, names&& ns, const variable* var)
+ {
+ using val_traits = value_traits<json_value>;
+ using obj_traits = value_traits<json_object>;
+
+ try
+ {
+ obj_traits::prepend (v, val_traits::convert (move (ns)));
+ }
+ catch (const invalid_argument& e)
+ {
+ // Note: ns is not guaranteed to be valid.
+ //
+ diag_record dr (fail);
+ dr << "invalid json object";
+
+ if (var != nullptr)
+ dr << " in variable " << var->name;
+
+ dr << ": " << e;
+ }
+ }
+
+ const json_object value_traits<json_object>::empty_instance;
+ const char* const value_traits<json_object>::type_name = "json_object";
+
+ const value_type value_traits<json_object>::value_type
+ {
+ type_name,
+ sizeof (json_object),
+ &value_traits<json_value>::value_type, // Base (assuming direct cast works
+ // for both).
+ true, // Container.
+ &value_traits<json_value>::value_type, // Element (json_value).
+ &default_dtor<json_object>,
+ &default_copy_ctor<json_object>,
+ &default_copy_assign<json_object>,
+ &json_object_assign,
+ &json_object_append,
+ &json_object_prepend,
+ &json_reverse,
+ nullptr, // No cast (cast data_ directly).
+ &json_compare,
+ &default_empty<json_object>,
+ &json_subscript,
+ &json_iterate
+ };
+
// cmdline
//
cmdline value_traits<cmdline>::
diff --git a/libbuild2/variable.hxx b/libbuild2/variable.hxx
index 9d7b001..6b0b30e 100644
--- a/libbuild2/variable.hxx
+++ b/libbuild2/variable.hxx
@@ -15,6 +15,8 @@
#include <libbuild2/forward.hxx>
#include <libbuild2/utility.hxx>
+#include <libbuild2/json.hxx>
+
#include <libbuild2/context.hxx>
#include <libbuild2/target-type.hxx>
#include <libbuild2/diagnostics.hxx>
@@ -1201,6 +1203,65 @@ namespace build2
static const map_value_type<K, V> value_type;
};
+ // json
+ //
+ // Note that we do not expose json_member as a value type instead
+ // representing it as an object with one member. While we could expose
+ // member (and reverse it as a pair since there is no valid JSON
+ // representation for a standalone member), this doesn't seem to buy us much
+ // but will cause complications (for example, in supporting append/prepend).
+ // On the other hand, representing a member as an object only requires a bit
+ // of what looks like harmless looseness in a few contexts (such as the
+ // $json.member_*() functions).
+ //
+ template <>
+ struct LIBBUILD2_SYMEXPORT value_traits<json_value>
+ {
+ static_assert (sizeof (json_value) <= value::size_, "insufficient space");
+
+ static json_value convert (names&&);
+ static void assign (value&, json_value&&);
+ static void append (value&, json_value&&);
+ static void prepend (value&, json_value&&);
+ static bool empty (const json_value&); // null or empty array/object
+
+ static const json_value empty_instance; // null
+ static const char* const type_name;
+ static const build2::value_type value_type;
+ };
+
+ template <>
+ struct LIBBUILD2_SYMEXPORT value_traits<json_array>
+ {
+ static_assert (sizeof (json_array) <= value::size_, "insufficient space");
+
+ static json_array convert (names&&);
+ static void assign (value&, json_array&&);
+ static void append (value&, json_value&&); // Note: value, not array.
+ static void prepend (value&, json_value&&);
+ static bool empty (const json_array& v) {return v.array.empty ();}
+
+ static const json_array empty_instance; // empty array
+ static const char* const type_name;
+ static const build2::value_type value_type;
+ };
+
+ template <>
+ struct LIBBUILD2_SYMEXPORT value_traits<json_object>
+ {
+ static_assert (sizeof (json_object) <= value::size_, "insufficient space");
+
+ static json_object convert (names&&);
+ static void assign (value&, json_object&&);
+ static void append (value&, json_value&&); // Note: value, not object.
+ static void prepend (value&, json_value&&);
+ static bool empty (const json_object& v) {return v.object.empty ();}
+
+ static const json_object empty_instance; // empty object
+ static const char* const type_name;
+ static const build2::value_type value_type;
+ };
+
// Canned command line to be re-lexed (used in {Build,Test}scripts).
//
// Note that because the executable can be specific as a target or as
diff --git a/libbuild2/variable.ixx b/libbuild2/variable.ixx
index 51c35fd..b8f80e3 100644
--- a/libbuild2/variable.ixx
+++ b/libbuild2/variable.ixx
@@ -906,6 +906,113 @@ namespace build2
new (&v.data_) map<K, V> (move (x));
}
+ // json
+ //
+ inline bool value_traits<json_value>::
+ empty (const json_value& v)
+ {
+ // Note: should be consistent with $json.size().
+ //
+ switch (v.type)
+ {
+ case json_type::null: return true;
+ case json_type::boolean:
+ case json_type::signed_number:
+ case json_type::unsigned_number:
+ case json_type::hexadecimal_number:
+ case json_type::string: break;
+ case json_type::array: return v.array.empty ();
+ case json_type::object: return v.object.empty ();
+ }
+
+ return false;
+ }
+
+ inline void value_traits<json_value>::
+ assign (value& v, json_value&& x)
+ {
+ if (v)
+ v.as<json_value> () = move (x);
+ else
+ new (&v.data_) json_value (move (x));
+ }
+
+ inline void value_traits<json_value>::
+ append (value& v, json_value&& x)
+ {
+ if (v)
+ v.as<json_value> ().append (move (x));
+ else
+ new (&v.data_) json_value (move (x));
+ }
+
+ inline void value_traits<json_value>::
+ prepend (value& v, json_value&& x)
+ {
+ if (v)
+ v.as<json_value> ().prepend (move (x));
+ else
+ new (&v.data_) json_value (move (x));
+ }
+
+ // json_array
+ //
+ inline void value_traits<json_array>::
+ assign (value& v, json_array&& x)
+ {
+ if (v)
+ v.as<json_array> () = move (x);
+ else
+ new (&v.data_) json_array (move (x));
+ }
+
+ inline void value_traits<json_array>::
+ append (value& v, json_value&& x)
+ {
+ if (!v)
+ new (&v.data_) json_array ();
+
+ v.as<json_array> ().append (move (x));
+ }
+
+ inline void value_traits<json_array>::
+ prepend (value& v, json_value&& x)
+ {
+ if (!v)
+ new (&v.data_) json_array ();
+
+ v.as<json_array> ().prepend (move (x));
+ }
+
+ // json_object
+ //
+ inline void value_traits<json_object>::
+ assign (value& v, json_object&& x)
+ {
+ if (v)
+ v.as<json_object> () = move (x);
+ else
+ new (&v.data_) json_object (move (x));
+ }
+
+ inline void value_traits<json_object>::
+ append (value& v, json_value&& x)
+ {
+ if (!v)
+ new (&v.data_) json_object ();
+
+ v.as<json_object> ().append (move (x));
+ }
+
+ inline void value_traits<json_object>::
+ prepend (value& v, json_value&& x)
+ {
+ if (!v)
+ new (&v.data_) json_object ();
+
+ v.as<json_object> ().prepend (move (x));
+ }
+
// variable_pool
//
inline const variable* variable_pool::