1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc. All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
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6 // modification, are permitted provided that the following conditions are
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8 //
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10 // notice, this list of conditions and the following disclaimer.
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13 // in the documentation and/or other materials provided with the
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18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31 #include <google/protobuf/util/internal/field_mask_utility.h>
32
33 #include <google/protobuf/stubs/strutil.h>
34 #include <google/protobuf/stubs/status_macros.h>
35
36 namespace google {
37 namespace protobuf {
38 namespace util {
39 namespace converter {
40
41 namespace {
CallPathSink(PathSinkCallback path_sink,StringPiece arg)42 inline util::Status CallPathSink(PathSinkCallback path_sink,
43 StringPiece arg) {
44 return path_sink->Run(arg);
45 }
46
CreatePublicError(util::error::Code code,const string & message)47 util::Status CreatePublicError(util::error::Code code,
48 const string& message) {
49 return util::Status(code, message);
50 }
51
52 // Appends a FieldMask path segment to a prefix.
AppendPathSegmentToPrefix(StringPiece prefix,StringPiece segment)53 string AppendPathSegmentToPrefix(StringPiece prefix, StringPiece segment) {
54 if (prefix.empty()) {
55 return segment.ToString();
56 }
57 if (segment.empty()) {
58 return prefix.ToString();
59 }
60 // If the segment is a map key, appends it to the prefix without the ".".
61 if (segment.starts_with("[\"")) {
62 return StrCat(prefix, segment);
63 }
64 return StrCat(prefix, ".", segment);
65 }
66
67 } // namespace
68
ConvertFieldMaskPath(const StringPiece path,ConverterCallback converter)69 string ConvertFieldMaskPath(const StringPiece path,
70 ConverterCallback converter) {
71 string result;
72 result.reserve(path.size() << 1);
73
74 bool is_quoted = false;
75 bool is_escaping = false;
76 int current_segment_start = 0;
77
78 // Loops until 1 passed the end of the input to make handling the last
79 // segment easier.
80 for (size_t i = 0; i <= path.size(); ++i) {
81 // Outputs quoted string as-is.
82 if (is_quoted) {
83 if (i == path.size()) {
84 break;
85 }
86 result.push_back(path[i]);
87 if (is_escaping) {
88 is_escaping = false;
89 } else if (path[i] == '\\') {
90 is_escaping = true;
91 } else if (path[i] == '\"') {
92 current_segment_start = i + 1;
93 is_quoted = false;
94 }
95 continue;
96 }
97 if (i == path.size() || path[i] == '.' || path[i] == '(' ||
98 path[i] == ')' || path[i] == '\"') {
99 result += converter(
100 path.substr(current_segment_start, i - current_segment_start));
101 if (i < path.size()) {
102 result.push_back(path[i]);
103 }
104 current_segment_start = i + 1;
105 }
106 if (i < path.size() && path[i] == '\"') {
107 is_quoted = true;
108 }
109 }
110 return result;
111 }
112
DecodeCompactFieldMaskPaths(StringPiece paths,PathSinkCallback path_sink)113 util::Status DecodeCompactFieldMaskPaths(StringPiece paths,
114 PathSinkCallback path_sink) {
115 stack<string> prefix;
116 int length = paths.length();
117 int previous_position = 0;
118 bool in_map_key = false;
119 bool is_escaping = false;
120 // Loops until 1 passed the end of the input to make the handle of the last
121 // segment easier.
122 for (int i = 0; i <= length; ++i) {
123 if (i != length) {
124 // Skips everything in a map key until we hit the end of it, which is
125 // marked by an un-escaped '"' immediately followed by a ']'.
126 if (in_map_key) {
127 if (is_escaping) {
128 is_escaping = false;
129 continue;
130 }
131 if (paths[i] == '\\') {
132 is_escaping = true;
133 continue;
134 }
135 if (paths[i] != '\"') {
136 continue;
137 }
138 // Un-escaped '"' must be followed with a ']'.
139 if (i >= length - 1 || paths[i + 1] != ']') {
140 return util::Status(
141 util::error::INVALID_ARGUMENT,
142 StrCat("Invalid FieldMask '", paths,
143 "'. Map keys should be represented as [\"some_key\"]."));
144 }
145 // The end of the map key ("\"]") has been found.
146 in_map_key = false;
147 // Skips ']'.
148 i++;
149 // Checks whether the key ends at the end of a path segment.
150 if (i < length - 1 && paths[i + 1] != '.' && paths[i + 1] != ',' &&
151 paths[i + 1] != ')' && paths[i + 1] != '(') {
152 return util::Status(
153 util::error::INVALID_ARGUMENT,
154 StrCat("Invalid FieldMask '", paths,
155 "'. Map keys should be at the end of a path segment."));
156 }
157 is_escaping = false;
158 continue;
159 }
160
161 // We are not in a map key, look for the start of one.
162 if (paths[i] == '[') {
163 if (i >= length - 1 || paths[i + 1] != '\"') {
164 return util::Status(
165 util::error::INVALID_ARGUMENT,
166 StrCat("Invalid FieldMask '", paths,
167 "'. Map keys should be represented as [\"some_key\"]."));
168 }
169 // "[\"" starts a map key.
170 in_map_key = true;
171 i++; // Skips the '\"'.
172 continue;
173 }
174 // If the current character is not a special character (',', '(' or ')'),
175 // continue to the next.
176 if (paths[i] != ',' && paths[i] != ')' && paths[i] != '(') {
177 continue;
178 }
179 }
180 // Gets the current segment - sub-string between previous position (after
181 // '(', ')', ',', or the beginning of the input) and the current position.
182 StringPiece segment =
183 paths.substr(previous_position, i - previous_position);
184 string current_prefix = prefix.empty() ? "" : prefix.top();
185
186 if (i < length && paths[i] == '(') {
187 // Builds a prefix and save it into the stack.
188 prefix.push(AppendPathSegmentToPrefix(current_prefix, segment));
189 } else if (!segment.empty()) {
190 // When the current charactor is ')', ',' or the current position has
191 // passed the end of the input, builds and outputs a new paths by
192 // concatenating the last prefix with the current segment.
193 RETURN_IF_ERROR(CallPathSink(
194 path_sink, AppendPathSegmentToPrefix(current_prefix, segment)));
195 }
196
197 // Removes the last prefix after seeing a ')'.
198 if (i < length && paths[i] == ')') {
199 if (prefix.empty()) {
200 return util::Status(
201 util::error::INVALID_ARGUMENT,
202 StrCat("Invalid FieldMask '", paths,
203 "'. Cannot find matching '(' for all ')'."));
204 }
205 prefix.pop();
206 }
207 previous_position = i + 1;
208 }
209 if (in_map_key) {
210 return util::Status(util::error::INVALID_ARGUMENT,
211 StrCat("Invalid FieldMask '", paths,
212 "'. Cannot find matching ']' for all '['."));
213 }
214 if (!prefix.empty()) {
215 return util::Status(util::error::INVALID_ARGUMENT,
216 StrCat("Invalid FieldMask '", paths,
217 "'. Cannot find matching ')' for all '('."));
218 }
219 return util::Status::OK;
220 }
221
222 } // namespace converter
223 } // namespace util
224 } // namespace protobuf
225 } // namespace google
226