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Diffstat (limited to 'libbuild2/json.cxx')
| -rw-r--r-- | libbuild2/json.cxx | 856 |
1 files changed, 856 insertions, 0 deletions
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 +} |