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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10 // notice, this list of conditions and the following disclaimer.
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18 //
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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/util/internal/utility.h>
34 #include <google/protobuf/stubs/status.h>
35 #include <google/protobuf/stubs/strutil.h>
36 #include <google/protobuf/stubs/status_macros.h>
37
38 // Must be included last.
39 #include <google/protobuf/port_def.inc>
40
41 namespace google {
42 namespace protobuf {
43 namespace util {
44 namespace converter {
45
46 namespace {
47
48 // Appends a FieldMask path segment to a prefix.
AppendPathSegmentToPrefix(StringPiece prefix,StringPiece segment)49 std::string AppendPathSegmentToPrefix(StringPiece prefix,
50 StringPiece segment) {
51 if (prefix.empty()) {
52 return std::string(segment);
53 }
54 if (segment.empty()) {
55 return std::string(prefix);
56 }
57 // If the segment is a map key, appends it to the prefix without the ".".
58 if (HasPrefixString(segment, "[\"")) {
59 return StrCat(prefix, segment);
60 }
61 return StrCat(prefix, ".", segment);
62 }
63
64 } // namespace
65
ConvertFieldMaskPath(const StringPiece path,ConverterCallback converter)66 std::string ConvertFieldMaskPath(const StringPiece path,
67 ConverterCallback converter) {
68 std::string result;
69 result.reserve(path.size() << 1);
70
71 bool is_quoted = false;
72 bool is_escaping = false;
73 int current_segment_start = 0;
74
75 // Loops until 1 passed the end of the input to make handling the last
76 // segment easier.
77 for (size_t i = 0; i <= path.size(); ++i) {
78 // Outputs quoted string as-is.
79 if (is_quoted) {
80 if (i == path.size()) {
81 break;
82 }
83 result.push_back(path[i]);
84 if (is_escaping) {
85 is_escaping = false;
86 } else if (path[i] == '\\') {
87 is_escaping = true;
88 } else if (path[i] == '\"') {
89 current_segment_start = i + 1;
90 is_quoted = false;
91 }
92 continue;
93 }
94 if (i == path.size() || path[i] == '.' || path[i] == '(' ||
95 path[i] == ')' || path[i] == '\"') {
96 result += converter(
97 path.substr(current_segment_start, i - current_segment_start));
98 if (i < path.size()) {
99 result.push_back(path[i]);
100 }
101 current_segment_start = i + 1;
102 }
103 if (i < path.size() && path[i] == '\"') {
104 is_quoted = true;
105 }
106 }
107 return result;
108 }
109
DecodeCompactFieldMaskPaths(StringPiece paths,PathSinkCallback path_sink)110 util::Status DecodeCompactFieldMaskPaths(StringPiece paths,
111 PathSinkCallback path_sink) {
112 std::stack<std::string> prefix;
113 int length = paths.length();
114 int previous_position = 0;
115 bool in_map_key = false;
116 bool is_escaping = false;
117 // Loops until 1 passed the end of the input to make the handle of the last
118 // segment easier.
119 for (int i = 0; i <= length; ++i) {
120 if (i != length) {
121 // Skips everything in a map key until we hit the end of it, which is
122 // marked by an un-escaped '"' immediately followed by a ']'.
123 if (in_map_key) {
124 if (is_escaping) {
125 is_escaping = false;
126 continue;
127 }
128 if (paths[i] == '\\') {
129 is_escaping = true;
130 continue;
131 }
132 if (paths[i] != '\"') {
133 continue;
134 }
135 // Un-escaped '"' must be followed with a ']'.
136 if (i >= length - 1 || paths[i + 1] != ']') {
137 return util::Status(
138 util::error::INVALID_ARGUMENT,
139 StrCat(
140 "Invalid FieldMask '", paths,
141 "'. Map keys should be represented as [\"some_key\"]."));
142 }
143 // The end of the map key ("\"]") has been found.
144 in_map_key = false;
145 // Skips ']'.
146 i++;
147 // Checks whether the key ends at the end of a path segment.
148 if (i < length - 1 && paths[i + 1] != '.' && paths[i + 1] != ',' &&
149 paths[i + 1] != ')' && paths[i + 1] != '(') {
150 return util::Status(
151 util::error::INVALID_ARGUMENT,
152 StrCat(
153 "Invalid FieldMask '", paths,
154 "'. Map keys should be at the end of a path segment."));
155 }
156 is_escaping = false;
157 continue;
158 }
159
160 // We are not in a map key, look for the start of one.
161 if (paths[i] == '[') {
162 if (i >= length - 1 || paths[i + 1] != '\"') {
163 return util::Status(
164 util::error::INVALID_ARGUMENT,
165 StrCat(
166 "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 std::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 character 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(
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(
211 util::error::INVALID_ARGUMENT,
212 StrCat("Invalid FieldMask '", paths,
213 "'. Cannot find matching ']' for all '['."));
214 }
215 if (!prefix.empty()) {
216 return util::Status(
217 util::error::INVALID_ARGUMENT,
218 StrCat("Invalid FieldMask '", paths,
219 "'. Cannot find matching ')' for all '('."));
220 }
221 return util::Status();
222 }
223
224 } // namespace converter
225 } // namespace util
226 } // namespace protobuf
227 } // namespace google
228