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// Copyright 2011 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "depfile_parser.h"
// A note on backslashes in Makefiles, from reading the docs:
// Backslash-newline is the line continuation character.
// Backslash-# escapes a # (otherwise meaningful as a comment start).
// Backslash-% escapes a % (otherwise meaningful as a special).
// Finally, quoting the GNU manual, "Backslashes that are not in danger
// of quoting ‘%’ characters go unmolested."
// How do you end a line with a backslash? The netbsd Make docs suggest
// reading the result of a shell command echoing a backslash!
//
// Rather than implement all of above, we do a simpler thing here:
// Backslashes escape a set of characters (see "escapes" defined below),
// otherwise they are passed through verbatim.
// If anyone actually has depfiles that rely on the more complicated
// behavior we can adjust this.
bool DepfileParser::Parse(string* content, string* err) {
// in: current parser input point.
// end: end of input.
// parsing_targets: whether we are parsing targets or dependencies.
char* in = &(*content)[0];
char* end = in + content->size();
bool parsing_targets = true;
while (in < end) {
// out: current output point (typically same as in, but can fall behind
// as we de-escape backslashes).
char* out = in;
// filename: start of the current parsed filename.
char* filename = out;
for (;;) {
// start: beginning of the current parsed span.
const char* start = in;
/*!re2c
re2c:define:YYCTYPE = "char";
re2c:define:YYCURSOR = in;
re2c:define:YYLIMIT = end;
re2c:yyfill:enable = 0;
re2c:indent:top = 2;
re2c:indent:string = " ";
nul = "\000";
escape = [ \\#*$[|];
'\\' escape {
// De-escape backslashed character.
*out++ = yych;
continue;
}
'\\' [^\000\n] {
// Let backslash before other characters through verbatim.
*out++ = '\\';
*out++ = yych;
continue;
}
[a-zA-Z0-9+,/_:.~-]+ {
// Got a span of plain text.
int len = in - start;
// Need to shift it over if we're overwriting backslashes.
if (out < start)
memmove(out, start, len);
out += len;
continue;
}
nul {
break;
}
[^] {
// For any other character (e.g. whitespace), swallow it here,
// allowing the outer logic to loop around again.
break;
}
*/
}
int len = out - filename;
const bool is_target = parsing_targets;
if (len > 0 && filename[len - 1] == ':') {
len--; // Strip off trailing colon, if any.
parsing_targets = false;
}
if (len == 0)
continue;
if (!is_target) {
ins_.push_back(StringPiece(filename, len));
} else if (!out_.str_) {
out_ = StringPiece(filename, len);
} else if (out_ != StringPiece(filename, len)) {
*err = "depfile has multiple output paths.";
return false;
}
}
return true;
}
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