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depfile_parser.cc
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1 /* Generated by re2c 0.16 */
2 // Copyright 2011 Google Inc. All Rights Reserved.
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 // http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 
16 #include "depfile_parser.h"
17 
18 // A note on backslashes in Makefiles, from reading the docs:
19 // Backslash-newline is the line continuation character.
20 // Backslash-# escapes a # (otherwise meaningful as a comment start).
21 // Backslash-% escapes a % (otherwise meaningful as a special).
22 // Finally, quoting the GNU manual, "Backslashes that are not in danger
23 // of quoting ‘%’ characters go unmolested."
24 // How do you end a line with a backslash? The netbsd Make docs suggest
25 // reading the result of a shell command echoing a backslash!
26 //
27 // Rather than implement all of above, we do a simpler thing here:
28 // Backslashes escape a set of characters (see "escapes" defined below),
29 // otherwise they are passed through verbatim.
30 // If anyone actually has depfiles that rely on the more complicated
31 // behavior we can adjust this.
32 bool DepfileParser::Parse(string* content, string* err) {
33  // in: current parser input point.
34  // end: end of input.
35  // parsing_targets: whether we are parsing targets or dependencies.
36  char* in = &(*content)[0];
37  char* end = in + content->size();
38  bool parsing_targets = true;
39  while (in < end) {
40  // out: current output point (typically same as in, but can fall behind
41  // as we de-escape backslashes).
42  char* out = in;
43  // filename: start of the current parsed filename.
44  char* filename = out;
45  for (;;) {
46  // start: beginning of the current parsed span.
47  const char* start = in;
48 
49  {
50  char yych;
51  static const unsigned char yybm[] = {
52  0, 0, 0, 0, 0, 0, 0, 0,
53  0, 0, 0, 0, 0, 0, 0, 0,
54  0, 0, 0, 0, 0, 0, 0, 0,
55  0, 0, 0, 0, 0, 0, 0, 0,
56  0, 128, 0, 0, 0, 0, 0, 0,
57  128, 128, 0, 128, 128, 128, 128, 128,
58  128, 128, 128, 128, 128, 128, 128, 128,
59  128, 128, 128, 0, 0, 128, 0, 0,
60  128, 128, 128, 128, 128, 128, 128, 128,
61  128, 128, 128, 128, 128, 128, 128, 128,
62  128, 128, 128, 128, 128, 128, 128, 128,
63  128, 128, 128, 0, 0, 0, 0, 128,
64  0, 128, 128, 128, 128, 128, 128, 128,
65  128, 128, 128, 128, 128, 128, 128, 128,
66  128, 128, 128, 128, 128, 128, 128, 128,
67  128, 128, 128, 128, 0, 128, 128, 0,
68  0, 0, 0, 0, 0, 0, 0, 0,
69  0, 0, 0, 0, 0, 0, 0, 0,
70  0, 0, 0, 0, 0, 0, 0, 0,
71  0, 0, 0, 0, 0, 0, 0, 0,
72  0, 0, 0, 0, 0, 0, 0, 0,
73  0, 0, 0, 0, 0, 0, 0, 0,
74  0, 0, 0, 0, 0, 0, 0, 0,
75  0, 0, 0, 0, 0, 0, 0, 0,
76  0, 0, 0, 0, 0, 0, 0, 0,
77  0, 0, 0, 0, 0, 0, 0, 0,
78  0, 0, 0, 0, 0, 0, 0, 0,
79  0, 0, 0, 0, 0, 0, 0, 0,
80  0, 0, 0, 0, 0, 0, 0, 0,
81  0, 0, 0, 0, 0, 0, 0, 0,
82  0, 0, 0, 0, 0, 0, 0, 0,
83  0, 0, 0, 0, 0, 0, 0, 0,
84  };
85  yych = *in;
86  if (yybm[0+yych] & 128) {
87  goto yy6;
88  }
89  if (yych <= '$') {
90  if (yych <= 0x00) goto yy2;
91  if (yych <= '#') goto yy4;
92  goto yy9;
93  } else {
94  if (yych == '\\') goto yy10;
95  goto yy4;
96  }
97 yy2:
98  ++in;
99  {
100  break;
101  }
102 yy4:
103  ++in;
104 yy5:
105  {
106  // For any other character (e.g. whitespace), swallow it here,
107  // allowing the outer logic to loop around again.
108  break;
109  }
110 yy6:
111  ++in;
112  yych = *in;
113  if (yybm[0+yych] & 128) {
114  goto yy6;
115  }
116  {
117  // Got a span of plain text.
118  int len = (int)(in - start);
119  // Need to shift it over if we're overwriting backslashes.
120  if (out < start)
121  memmove(out, start, len);
122  out += len;
123  continue;
124  }
125 yy9:
126  yych = *++in;
127  if (yych == '$') goto yy11;
128  goto yy5;
129 yy10:
130  yych = *++in;
131  if (yych <= '"') {
132  if (yych <= '\f') {
133  if (yych <= 0x00) goto yy5;
134  if (yych == '\n') goto yy5;
135  goto yy13;
136  } else {
137  if (yych <= '\r') goto yy5;
138  if (yych == ' ') goto yy15;
139  goto yy13;
140  }
141  } else {
142  if (yych <= 'Z') {
143  if (yych <= '#') goto yy15;
144  if (yych == '*') goto yy15;
145  goto yy13;
146  } else {
147  if (yych <= '\\') goto yy15;
148  if (yych == '|') goto yy15;
149  goto yy13;
150  }
151  }
152 yy11:
153  ++in;
154  {
155  // De-escape dollar character.
156  *out++ = '$';
157  continue;
158  }
159 yy13:
160  ++in;
161  {
162  // Let backslash before other characters through verbatim.
163  *out++ = '\\';
164  *out++ = yych;
165  continue;
166  }
167 yy15:
168  ++in;
169  {
170  // De-escape backslashed character.
171  *out++ = yych;
172  continue;
173  }
174  }
175 
176  }
177 
178  int len = (int)(out - filename);
179  const bool is_target = parsing_targets;
180  if (len > 0 && filename[len - 1] == ':') {
181  len--; // Strip off trailing colon, if any.
182  parsing_targets = false;
183  }
184 
185  if (len == 0)
186  continue;
187 
188  if (!is_target) {
189  ins_.push_back(StringPiece(filename, len));
190  } else if (!out_.str_) {
191  out_ = StringPiece(filename, len);
192  } else if (out_ != StringPiece(filename, len)) {
193  *err = "depfile has multiple output paths";
194  return false;
195  }
196  }
197  return true;
198 }
const char * str_
Definition: string_piece.h:49
StringPiece represents a slice of a string whose memory is managed externally.
Definition: string_piece.h:27
bool Parse(string *content, string *err)
Parse an input file.
vector< StringPiece > ins_
StringPiece out_