1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
// 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"
#include "util.h"
#include <algorithm>
DepfileParser::DepfileParser(DepfileParserOptions options)
: options_(options)
{
}
// 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 follow what GCC/Clang produces:
// Backslashes escape a space or hash sign.
// When a space is preceded by 2N+1 backslashes, it is represents N backslashes
// followed by space.
// When a space is preceded by 2N backslashes, it represents 2N backslashes at
// the end of a filename.
// A hash sign is escaped by a single backslash. All other backslashes remain
// unchanged.
//
// 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 have_target = false;
bool parsing_targets = true;
bool poisoned_input = false;
while (in < end) {
bool have_newline = false;
// 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;
char* yymarker = NULL;
/*!re2c
re2c:define:YYCTYPE = "unsigned char";
re2c:define:YYCURSOR = in;
re2c:define:YYLIMIT = end;
re2c:define:YYMARKER = yymarker;
re2c:yyfill:enable = 0;
re2c:indent:top = 2;
re2c:indent:string = " ";
nul = "\000";
newline = '\r'?'\n';
'\\\\'* '\\ ' {
// 2N+1 backslashes plus space -> N backslashes plus space.
int len = (int)(in - start);
int n = len / 2 - 1;
if (out < start)
memset(out, '\\', n);
out += n;
*out++ = ' ';
continue;
}
'\\\\'+ ' ' {
// 2N backslashes plus space -> 2N backslashes, end of filename.
int len = (int)(in - start);
if (out < start)
memset(out, '\\', len - 1);
out += len - 1;
break;
}
'\\'+ '#' {
// De-escape hash sign, but preserve other leading backslashes.
int len = (int)(in - start);
if (len > 2 && out < start)
memset(out, '\\', len - 2);
out += len - 2;
*out++ = '#';
continue;
}
'\\'+ ':' [\x00\x20\r\n\t] {
// Backslash followed by : and whitespace.
// It is therefore normal text and not an escaped colon
int len = (int)(in - start - 1);
// Need to shift it over if we're overwriting backslashes.
if (out < start)
memmove(out, start, len);
out += len;
if (*(in - 1) == '\n')
have_newline = true;
break;
}
'\\'+ ':' {
// De-escape colon sign, but preserve other leading backslashes.
// Regular expression uses lookahead to make sure that no whitespace
// nor EOF follows. In that case it'd be the : at the end of a target
int len = (int)(in - start);
if (len > 2 && out < start)
memset(out, '\\', len - 2);
out += len - 2;
*out++ = ':';
continue;
}
'$$' {
// De-escape dollar character.
*out++ = '$';
continue;
}
'\\'+ [^\000\r\n] | [a-zA-Z0-9+,/_:.~()}{%=@\x5B\x5D!\x80-\xFF-]+ {
// Got a span of plain text.
int len = (int)(in - start);
// Need to shift it over if we're overwriting backslashes.
if (out < start)
memmove(out, start, len);
out += len;
continue;
}
nul {
break;
}
'\\' newline {
// A line continuation ends the current file name.
break;
}
newline {
// A newline ends the current file name and the current rule.
have_newline = true;
break;
}
[^] {
// For any other character (e.g. whitespace), swallow it here,
// allowing the outer logic to loop around again.
break;
}
*/
}
int len = (int)(out - filename);
const bool is_dependency = !parsing_targets;
if (len > 0 && filename[len - 1] == ':') {
len--; // Strip off trailing colon, if any.
parsing_targets = false;
have_target = true;
}
if (len > 0) {
StringPiece piece = StringPiece(filename, len);
// If we've seen this as an input before, skip it.
std::vector<StringPiece>::iterator pos = std::find(ins_.begin(), ins_.end(), piece);
if (pos == ins_.end()) {
if (is_dependency) {
if (poisoned_input) {
*err = "inputs may not also have inputs";
return false;
}
// New input.
ins_.push_back(piece);
} else {
// Check for a new output.
if (std::find(outs_.begin(), outs_.end(), piece) == outs_.end())
outs_.push_back(piece);
}
} else if (!is_dependency) {
// We've passed an input on the left side; reject new inputs.
poisoned_input = true;
}
}
if (have_newline) {
// A newline ends a rule so the next filename will be a new target.
parsing_targets = true;
poisoned_input = false;
}
}
if (!have_target) {
*err = "expected ':' in depfile";
return false;
}
return true;
}
|
