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// file : libbuild2/make-parser.cxx -*- C++ -*-
// license : MIT; see accompanying LICENSE file
#include <libbuild2/make-parser.hxx>
#include <libbuild2/diagnostics.hxx>
namespace build2
{
auto make_parser::
next (const string& l,
size_t& p,
const location& ll,
bool strict) -> pair<type, string>
{
assert (state != end);
pair<string, bool> r (
next (l, p, !strict ? state == prereqs : optional<bool> ()));
type t (state == prereqs ? type::prereq : type::target);
// Deal with the end.
//
if (r.second)
{
if (state == begin && r.first.empty ())
; // Skip leading blank line.
else
{
if (state != prereqs)
fail (ll) << "end of make dependency declaration before ':'";
state = end;
}
}
// Deal with the first target.
//
else if (state == begin && !r.first.empty ())
state = targets;
// Deal with `:`.
//
if (p != l.size () && l[p] == ':')
{
switch (state)
{
case begin: fail (ll) << "':' before make target"; break;
case targets: state = prereqs; break;
case prereqs: fail (ll) << "':' after make prerequisite"; break;
case end: break;
}
if (++p == l.size ())
state = end; // Not a mere optimization: the caller will get next line.
}
return pair<type, string> (t, move (r.first));
}
pair<string, bool> make_parser::
next (const string& l, size_t& p, optional<bool> prereq)
{
size_t n (l.size ());
// Skip leading spaces.
//
for (; p != n && l[p] == ' '; p++) ;
// Lines containing multiple targets/prerequisites are customarily 80
// characters max.
//
string r;
r.reserve (n - p);
// Scan the next target/prerequisite while watching out for escape
// sequences.
//
// @@ Can't we do better for the (common) case where nothing is escaped?
//
for (char c, q (prereq && *prereq ? '\0' : ':');
p != n && (c = l[p]) != ' ' && c != q; )
{
// If we have another character, then handle the escapes.
//
if (++p != n)
{
if (c == '\\')
{
// This may or may not be an escape sequence depending on whether
// what follows is "escapable".
//
switch (c = l[p])
{
case '\\':
case ' ':
case ':': ++p; break;
default: c = '\\'; // Restore.
}
}
else if (c == '$')
{
// Got to be another (escaped) '$'.
//
if (l[p] == '$')
++p;
}
}
// Note that the newline escape is not necessarily separated with space.
//
else if (c == '\\')
{
--p;
break;
}
r += c;
}
// Skip trailing spaces.
//
for (; p != n && l[p] == ' '; p++) ;
// Skip final '\' and determine if this is the end.
//
bool e (false);
if (p == n - 1)
{
if (l[p] == '\\')
p++;
}
else if (p == n)
e = true;
return pair<string, bool> (move (r), e);
}
}
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