/proc/self/cwd/src/http_template.cc

Source (jump to first uncovered line)
// Copyright 2016 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 <cassert>
#include <string>
#include <vector>

#include "grpc_transcoding/http_template.h"

namespace google {
namespace grpc {
namespace transcoding {

namespace {

// TODO: implement an error sink.

// HTTP Template Grammar:
// Questions:
//   - what are the constraints on LITERAL and IDENT?
//   - what is the character set for the grammar?
//
// Template = "/" | "/" Segments [ Verb ] ;
// Segments = Segment { "/" Segment } ;
// Segment  = "*" | "**" | LITERAL | Variable ;
// Variable = "{" FieldPath [ "=" Segments ] "}" ;
// FieldPath = IDENT { "." IDENT } ;
// Verb     = ":" LITERAL ;
class Parser {
 public:
  Parser(const std::string &input)
      : input_(input), tb_(0), te_(0), in_variable_(false) {}

  bool Parse() {
    if (!ParseTemplate() || !ConsumedAllInput()) {
      return false;
    }
    PostProcessVariables();
    return true;
  }

  std::vector<std::string> &segments() { return segments_; }
  std::string &verb() { return verb_; }
  std::vector<HttpTemplate::Variable> &variables() { return variables_; }

  // only constant path segments are allowed after '**'.
  bool ValidateParts() {
    bool found_wild_card = false;
    for (size_t i = 0; i < segments_.size(); i++) {
      if (!found_wild_card) {
        if (segments_[i] == HttpTemplate::kWildCardPathKey) {
          found_wild_card = true;
        }
      } else if (segments_[i] == HttpTemplate::kSingleParameterKey ||
                 segments_[i] == HttpTemplate::kWildCardPathPartKey ||
                 segments_[i] == HttpTemplate::kWildCardPathKey) {
        return false;
      }
    }
    return true;
  }

 private:
  // Template = "/" Segments [ Verb ] ;
  bool ParseTemplate() {
    if (!Consume('/')) {
      // Expected '/'
      return false;
    }
    if (!ParseSegments()) {
      return false;
    }

    if (EnsureCurrent() && current_char() == ':') {
      if (!ParseVerb()) {
        return false;
      }
    }
    return true;
  }

  // Segments = Segment { "/" Segment } ;
  bool ParseSegments() {
    if (!ParseSegment()) {
      return false;
    }

    for (;;) {
      if (!Consume('/')) break;
      if (!ParseSegment()) {
        return false;
      }
    }

    return true;
  }

  // Segment  = "*" | "**" | LITERAL | Variable ;
  bool ParseSegment() {
    if (!EnsureCurrent()) {
      return false;
    }
    switch (current_char()) {
      case '*': {
        Consume('*');
        if (Consume('*')) {
          // **
          segments_.push_back("**");
          if (in_variable_) {
            return MarkVariableHasWildCardPath();
          }
          return true;
        } else {
          segments_.push_back("*");
          return true;
        }
      }

      case '{':
        return ParseVariable();
      default:
        return ParseLiteralSegment();
    }
  }

  // Variable = "{" FieldPath [ "=" Segments ] "}" ;
  bool ParseVariable() {
    if (!Consume('{')) {
      return false;
    }
    if (!StartVariable()) {
      return false;
    }
    if (!ParseFieldPath()) {
      return false;
    }
    if (Consume('=')) {
      if (!ParseSegments()) {
        return false;
      }
    } else {
      // {field_path} is equivalent to {field_path=*}
      segments_.push_back("*");
    }
    if (!EndVariable()) {
      return false;
    }
    if (!Consume('}')) {
      return false;
    }
    return true;
  }

  bool ParseLiteralSegment() {
    std::string ls;
    if (!ParseLiteral(&ls)) {
      return false;
    }
    segments_.push_back(ls);
    return true;
  }

  // FieldPath = IDENT { "." IDENT } ;
  bool ParseFieldPath() {
    if (!ParseIdentifier()) {
      return false;
    }
    while (Consume('.')) {
      if (!ParseIdentifier()) {
        return false;
      }
    }
    return true;
  }

  // Verb     = ":" LITERAL ;
  bool ParseVerb() {
    if (!Consume(':')) return false;
    if (!ParseLiteral(&verb_)) return false;
    return true;
  }

  bool ParseIdentifier() {
    std::string idf;

    // Initialize to false to handle empty literal.
    bool result = false;

    while (NextChar()) {
      char c;
      switch (c = current_char()) {
        case '.':
        case '}':
        case '=':
          return result && AddFieldIdentifier(std::move(idf));
        default:
          Consume(c);
          idf.push_back(c);
          break;
      }
      result = true;
    }
    return result && AddFieldIdentifier(std::move(idf));
  }

  bool ParseLiteral(std::string *lit) {
    if (!EnsureCurrent()) {
      return false;
    }

    // Initialize to false in case we encounter an empty literal.
    bool result = false;

    for (;;) {
      char c;
      switch (c = current_char()) {
        case '/':
        case ':':
        case '}':
          return result;
        default:
          Consume(c);
          lit->push_back(c);
          break;
      }

      result = true;

      if (!NextChar()) {
        break;
      }
    }
    return result;
  }

  bool Consume(char c) {
    if (tb_ >= te_ && !NextChar()) {
      return false;
    }
    if (current_char() != c) {
      return false;
    }
    tb_++;
    return true;
  }

  bool ConsumedAllInput() { return tb_ >= input_.size(); }

  bool EnsureCurrent() { return tb_ < te_ || NextChar(); }

  bool NextChar() {
    if (te_ < input_.size()) {
      te_++;
      return true;
    } else {
      return false;
    }
  }

  // Returns the character looked at.
  char current_char() const {
    return tb_ < te_ && te_ <= input_.size() ? input_[te_ - 1] : -1;
  }

  HttpTemplate::Variable &CurrentVariable() { return variables_.back(); }

  bool StartVariable() {
    if (!in_variable_) {
      variables_.push_back(HttpTemplate::Variable{});
      CurrentVariable().start_segment = segments_.size();
      CurrentVariable().has_wildcard_path = false;
      in_variable_ = true;
      return true;
    } else {
      // nested variables are not allowed
      return false;
    }
  }

  bool EndVariable() {
    if (in_variable_ && !variables_.empty()) {
      CurrentVariable().end_segment = segments_.size();
      in_variable_ = false;
      return ValidateVariable(CurrentVariable());
    } else {
      // something's wrong we're not in a variable
      return false;
    }
  }

  bool AddFieldIdentifier(std::string id) {
    if (in_variable_ && !variables_.empty()) {
      CurrentVariable().field_path.emplace_back(std::move(id));
      return true;
    } else {
      // something's wrong we're not in a variable
      return false;
    }
  }

  bool MarkVariableHasWildCardPath() {
    if (in_variable_ && !variables_.empty()) {
      CurrentVariable().has_wildcard_path = true;
      return true;
    } else {
      // something's wrong we're not in a variable
      return false;
    }
  }

  bool ValidateVariable(const HttpTemplate::Variable &var) {
    return !var.field_path.empty() && (var.start_segment < var.end_segment) &&
           (var.end_segment <= static_cast<int>(segments_.size()));
  }

  void PostProcessVariables() {
    for (auto &var : variables_) {
      if (var.has_wildcard_path) {
        // if the variable contains a '**', store the end_positon
        // relative to the end, such that -1 corresponds to the end
        // of the path. As we only support fixed path after '**',
        // this will allow the matcher code to reconstruct the variable
        // value based on the url segments.
        var.end_segment = (var.end_segment - segments_.size() - 1);
      }
    }
  }

  const std::string &input_;

  // Token delimiter indexes
  size_t tb_;
  size_t te_;

  // are we in nested Segments of a variable?
  bool in_variable_;

  std::vector<std::string> segments_;
  std::string verb_;
  std::vector<HttpTemplate::Variable> variables_;
};

}  // namespace

const char HttpTemplate::kSingleParameterKey[] = "/.";

const char HttpTemplate::kWildCardPathPartKey[] = "*";

const char HttpTemplate::kWildCardPathKey[] = "**";

std::unique_ptr<HttpTemplate> HttpTemplate::Parse(const std::string &ht) {
  if (ht == "/") {
    return std::unique_ptr<HttpTemplate>(new HttpTemplate({}, {}, {}));
  }

  Parser p(ht);
  if (!p.Parse() || !p.ValidateParts()) {
    return nullptr;
  }

  return std::unique_ptr<HttpTemplate>(new HttpTemplate(
      std::move(p.segments()), std::move(p.verb()), std::move(p.variables())));
}

}  // namespace transcoding
}  // namespace grpc
}  // namespace google

Coverage Report

Created: 2024-02-25 06:31

Line	Count	Source (jump to first uncovered line)
1		// Copyright 2016 Google Inc. All Rights Reserved.
2		//
3		// Licensed under the Apache License, Version 2.0 (the "License");
4		// you may not use this file except in compliance with the License.
5		// You may obtain a copy of the License at
6		//
7		// http://www.apache.org/licenses/LICENSE-2.0
8		//
9		// Unless required by applicable law or agreed to in writing, software
10		// distributed under the License is distributed on an "AS IS" BASIS,
11		// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12		// See the License for the specific language governing permissions and
13		// limitations under the License.
14		//
15		////////////////////////////////////////////////////////////////////////////////
16		//
17		#include <cassert>
18		#include <string>
19		#include <vector>
20
21		#include "grpc_transcoding/http_template.h"
22
23		namespace google {
24		namespace grpc {
25		namespace transcoding {
26
27		namespace {
28
29		// TODO: implement an error sink.
30
31		// HTTP Template Grammar:
32		// Questions:
33		// - what are the constraints on LITERAL and IDENT?
34		// - what is the character set for the grammar?
35		//
36		// Template = "/" \| "/" Segments [ Verb ] ;
37		// Segments = Segment { "/" Segment } ;
38		// Segment = "" \| "*" \| LITERAL \| Variable ;
39		// Variable = "{" FieldPath [ "=" Segments ] "}" ;
40		// FieldPath = IDENT { "." IDENT } ;
41		// Verb = ":" LITERAL ;
42		class Parser {
43		public:
44		Parser(const std::string &input)
45	944	: input_(input), tb_(0), te_(0), in_variable_(false) {}
46
47	944	bool Parse() {
48	944	if (!ParseTemplate() \|\| !ConsumedAllInput()) {
49	486	return false;
50	486	}
51	458	PostProcessVariables();
52	458	return true;
53	944	}
54
55	386	std::vector<std::string> &segments() { return segments_; }
56	386	std::string &verb() { return verb_; }
57	386	std::vector<HttpTemplate::Variable> &variables() { return variables_; }
58
59		// only constant path segments are allowed after '**'.
60	458	bool ValidateParts() {
61	458	bool found_wild_card = false;
62	4.23M	for (size_t i = 0; i < segments_.size(); i++) {
63	4.23M	if (!found_wild_card) {
64	4.22M	if (segments_[i] == HttpTemplate::kWildCardPathKey) {
65	220	found_wild_card = true;
66	220	}
67	4.22M	} else if (segments_[i] == HttpTemplate::kSingleParameterKey \|\|
68	6.69k	segments_[i] == HttpTemplate::kWildCardPathPartKey \|\|
69	6.69k	segments_[i] == HttpTemplate::kWildCardPathKey) {
70	72	return false;
71	72	}
72	4.23M	}
73	386	return true;
74	458	}
75
76		private:
77		// Template = "/" Segments [ Verb ] ;
78	944	bool ParseTemplate() {
79	944	if (!Consume('/')) {
80		// Expected '/'
81	26	return false;
82	26	}
83	918	if (!ParseSegments()) {
84	321	return false;
85	321	}
86
87	597	if (EnsureCurrent() && current_char() == ':') {
88	69	if (!ParseVerb()) {
89	43	return false;
90	43	}
91	69	}
92	554	return true;
93	597	}
94
95		// Segments = Segment { "/" Segment } ;
96	9.51k	bool ParseSegments() {
97	9.51k	if (!ParseSegment()) {
98	117	return false;
99	117	}
100
101	6.41M	for (;;) {
102	6.41M	if (!Consume('/')) break;
103	6.41M	if (!ParseSegment()) {
104	230	return false;
105	230	}
106	6.41M	}
107
108	9.17k	return true;
109	9.40k	}
110
111		// Segment = "" \| "*" \| LITERAL \| Variable ;
112	6.42M	bool ParseSegment() {
113	6.42M	if (!EnsureCurrent()) {
114	51	return false;
115	51	}
116	6.42M	switch (current_char()) {
117	3.02M	case '*': {
118	3.02M	Consume('*');
119	3.02M	if (Consume('*')) {
120		// **
121	14.1k	segments_.push_back("**");
122	14.1k	if (in_variable_) {
123	9.22k	return MarkVariableHasWildCardPath();
124	9.22k	}
125	4.87k	return true;
126	3.01M	} else {
127	3.01M	segments_.push_back("*");
128	3.01M	return true;
129	3.01M	}
130	3.02M	}
131
132	370k	case '{':
133	370k	return ParseVariable();
134	3.02M	default:
135	3.02M	return ParseLiteralSegment();
136	6.42M	}
137	6.42M	}
138
139		// Variable = "{" FieldPath [ "=" Segments ] "}" ;
140	370k	bool ParseVariable() {
141	370k	if (!Consume('{')) {
142	0	return false;
143	0	}
144	370k	if (!StartVariable()) {
145	8	return false;
146	8	}
147	370k	if (!ParseFieldPath()) {
148	76	return false;
149	76	}
150	370k	if (Consume('=')) {
151	8.60k	if (!ParseSegments()) {
152	26	return false;
153	26	}
154	361k	} else {
155		// {field_path} is equivalent to {field_path=*}
156	361k	segments_.push_back("*");
157	361k	}
158	370k	if (!EndVariable()) {
159	0	return false;
160	0	}
161	370k	if (!Consume('}')) {
162	164	return false;
163	164	}
164	369k	return true;
165	370k	}
166
167	3.02M	bool ParseLiteralSegment() {
168	3.02M	std::string ls;
169	3.02M	if (!ParseLiteral(&ls)) {
170	22	return false;
171	22	}
172	3.02M	segments_.push_back(ls);
173	3.02M	return true;
174	3.02M	}
175
176		// FieldPath = IDENT { "." IDENT } ;
177	370k	bool ParseFieldPath() {
178	370k	if (!ParseIdentifier()) {
179	48	return false;
180	48	}
181	992k	while (Consume('.')) {
182	622k	if (!ParseIdentifier()) {
183	28	return false;
184	28	}
185	622k	}
186	370k	return true;
187	370k	}
188
189		// Verb = ":" LITERAL ;
190	69	bool ParseVerb() {
191	69	if (!Consume(':')) return false;
192	69	if (!ParseLiteral(&verb_)) return false;
193	26	return true;
194	69	}
195
196	992k	bool ParseIdentifier() {
197	992k	std::string idf;
198
199		// Initialize to false to handle empty literal.
200	992k	bool result = false;
201
202	7.42M	while (NextChar()) {
203	7.42M	char c;
204	7.42M	switch (c = current_char()) {
205	622k	case '.':
206	983k	case '}':
207	992k	case '=':
208	992k	return result && AddFieldIdentifier(std::move(idf));
209	6.42M	default:
210	6.42M	Consume(c);
211	6.42M	idf.push_back(c);
212	6.42M	break;
213	7.42M	}
214	6.42M	result = true;
215	6.42M	}
216	177	return result && AddFieldIdentifier(std::move(idf));
217	992k	}
218
219	3.02M	bool ParseLiteral(std::string *lit) {
220	3.02M	if (!EnsureCurrent()) {
221	39	return false;
222	39	}
223
224		// Initialize to false in case we encounter an empty literal.
225	3.02M	bool result = false;
226
227	21.4M	for (;;) {
228	21.4M	char c;
229	21.4M	switch (c = current_char()) {
230	3.01M	case '/':
231	3.01M	case ':':
232	3.02M	case '}':
233	3.02M	return result;
234	18.4M	default:
235	18.4M	Consume(c);
236	18.4M	lit->push_back(c);
237	18.4M	break;
238	21.4M	}
239
240	18.4M	result = true;
241
242	18.4M	if (!NextChar()) {
243	323	break;
244	323	}
245	18.4M	}
246	323	return result;
247	3.02M	}
248
249	39.4M	bool Consume(char c) {
250	39.4M	if (tb_ >= te_ && !NextChar()) {
251	930	return false;
252	930	}
253	39.4M	if (current_char() != c) {
254	3.75M	return false;
255	3.75M	}
256	35.7M	tb_++;
257	35.7M	return true;
258	39.4M	}
259
260	554	bool ConsumedAllInput() { return tb_ >= input_.size(); }
261
262	9.44M	bool EnsureCurrent() { return tb_ < te_ \|\| NextChar(); }
263
264	35.7M	bool NextChar() {
265	35.7M	if (te_ < input_.size()) {
266	35.7M	te_++;
267	35.7M	return true;
268	35.7M	} else {
269	1.95k	return false;
270	1.95k	}
271	35.7M	}
272
273		// Returns the character looked at.
274	74.7M	char current_char() const {
275	74.7M	return tb_ < te_ && te_ <= input_.size() ? input_[te_ - 1] : -1;
276	74.7M	}
277
278	2.48M	HttpTemplate::Variable &CurrentVariable() { return variables_.back(); }
279
280	370k	bool StartVariable() {
281	370k	if (!in_variable_) {
282	370k	variables_.push_back(HttpTemplate::Variable{});
283	370k	CurrentVariable().start_segment = segments_.size();
284	370k	CurrentVariable().has_wildcard_path = false;
285	370k	in_variable_ = true;
286	370k	return true;
287	370k	} else {
288		// nested variables are not allowed
289	8	return false;
290	8	}
291	370k	}
292
293	370k	bool EndVariable() {
294	370k	if (in_variable_ && !variables_.empty()) {
295	370k	CurrentVariable().end_segment = segments_.size();
296	370k	in_variable_ = false;
297	370k	return ValidateVariable(CurrentVariable());
298	370k	} else {
299		// something's wrong we're not in a variable
300	0	return false;
301	0	}
302	370k	}
303
304	992k	bool AddFieldIdentifier(std::string id) {
305	992k	if (in_variable_ && !variables_.empty()) {
306	992k	CurrentVariable().field_path.emplace_back(std::move(id));
307	992k	return true;
308	992k	} else {
309		// something's wrong we're not in a variable
310	0	return false;
311	0	}
312	992k	}
313
314	9.22k	bool MarkVariableHasWildCardPath() {
315	9.22k	if (in_variable_ && !variables_.empty()) {
316	9.22k	CurrentVariable().has_wildcard_path = true;
317	9.22k	return true;
318	9.22k	} else {
319		// something's wrong we're not in a variable
320	0	return false;
321	0	}
322	9.22k	}
323
324	370k	bool ValidateVariable(const HttpTemplate::Variable &var) {
325	370k	return !var.field_path.empty() && (var.start_segment < var.end_segment) &&
326	370k	(var.end_segment <= static_cast<int>(segments_.size()));
327	370k	}
328
329	458	void PostProcessVariables() {
330	246k	for (auto &var : variables_) {
331	246k	if (var.has_wildcard_path) {
332		// if the variable contains a '**', store the end_positon
333		// relative to the end, such that -1 corresponds to the end
334		// of the path. As we only support fixed path after '**',
335		// this will allow the matcher code to reconstruct the variable
336		// value based on the url segments.
337	2.93k	var.end_segment = (var.end_segment - segments_.size() - 1);
338	2.93k	}
339	246k	}
340	458	}
341
342		const std::string &input_;
343
344		// Token delimiter indexes
345		size_t tb_;
346		size_t te_;
347
348		// are we in nested Segments of a variable?
349		bool in_variable_;
350
351		std::vector<std::string> segments_;
352		std::string verb_;
353		std::vector<HttpTemplate::Variable> variables_;
354		};
355
356		} // namespace
357
358		const char HttpTemplate::kSingleParameterKey[] = "/.";
359
360		const char HttpTemplate::kWildCardPathPartKey[] = "*";
361
362		const char HttpTemplate::kWildCardPathKey[] = "**";
363
364	945	std::unique_ptr<HttpTemplate> HttpTemplate::Parse(const std::string &ht) {
365	945	if (ht == "/") {
366	1	return std::unique_ptr<HttpTemplate>(new HttpTemplate({}, {}, {}));
367	1	}
368
369	944	Parser p(ht);
370	944	if (!p.Parse() \|\| !p.ValidateParts()) {
371	558	return nullptr;
372	558	}
373
374	386	return std::unique_ptr<HttpTemplate>(new HttpTemplate(
375	386	std::move(p.segments()), std::move(p.verb()), std::move(p.variables())));
376	944	}
377
378		} // namespace transcoding
379		} // namespace grpc
380		} // namespace google