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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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/stubs/status.h>
34 #include <google/protobuf/stubs/strutil.h>
35 #include <google/protobuf/util/internal/utility.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::InvalidArgumentError(StrCat(
138 "Invalid FieldMask '", paths,
139 "'. Map keys should be represented as [\"some_key\"]."));
140 }
141 // The end of the map key ("\"]") has been found.
142 in_map_key = false;
143 // Skips ']'.
144 i++;
145 // Checks whether the key ends at the end of a path segment.
146 if (i < length - 1 && paths[i + 1] != '.' && paths[i + 1] != ',' &&
147 paths[i + 1] != ')' && paths[i + 1] != '(') {
148 return util::InvalidArgumentError(StrCat(
149 "Invalid FieldMask '", paths,
150 "'. Map keys should be at the end of a path segment."));
151 }
152 is_escaping = false;
153 continue;
154 }
155
156 // We are not in a map key, look for the start of one.
157 if (paths[i] == '[') {
158 if (i >= length - 1 || paths[i + 1] != '\"') {
159 return util::InvalidArgumentError(StrCat(
160 "Invalid FieldMask '", paths,
161 "'. Map keys should be represented as [\"some_key\"]."));
162 }
163 // "[\"" starts a map key.
164 in_map_key = true;
165 i++; // Skips the '\"'.
166 continue;
167 }
168 // If the current character is not a special character (',', '(' or ')'),
169 // continue to the next.
170 if (paths[i] != ',' && paths[i] != ')' && paths[i] != '(') {
171 continue;
172 }
173 }
174 // Gets the current segment - sub-string between previous position (after
175 // '(', ')', ',', or the beginning of the input) and the current position.
176 StringPiece segment =
177 paths.substr(previous_position, i - previous_position);
178 std::string current_prefix = prefix.empty() ? "" : prefix.top();
179
180 if (i < length && paths[i] == '(') {
181 // Builds a prefix and save it into the stack.
182 prefix.push(AppendPathSegmentToPrefix(current_prefix, segment));
183 } else if (!segment.empty()) {
184 // When the current character is ')', ',' or the current position has
185 // passed the end of the input, builds and outputs a new paths by
186 // concatenating the last prefix with the current segment.
187 RETURN_IF_ERROR(
188 path_sink(AppendPathSegmentToPrefix(current_prefix, segment)));
189 }
190
191 // Removes the last prefix after seeing a ')'.
192 if (i < length && paths[i] == ')') {
193 if (prefix.empty()) {
194 return util::InvalidArgumentError(
195 StrCat("Invalid FieldMask '", paths,
196 "'. Cannot find matching '(' for all ')'."));
197 }
198 prefix.pop();
199 }
200 previous_position = i + 1;
201 }
202 if (in_map_key) {
203 return util::InvalidArgumentError(
204 StrCat("Invalid FieldMask '", paths,
205 "'. Cannot find matching ']' for all '['."));
206 }
207 if (!prefix.empty()) {
208 return util::InvalidArgumentError(
209 StrCat("Invalid FieldMask '", paths,
210 "'. Cannot find matching ')' for all '('."));
211 }
212 return util::Status();
213 }
214
215 } // namespace converter
216 } // namespace util
217 } // namespace protobuf
218 } // namespace google
219