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1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc.  All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 //     * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 //     * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 //     * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 
31 // Author: kenton@google.com (Kenton Varda)
32 //  Based on original Protocol Buffers design by
33 //  Sanjay Ghemawat, Jeff Dean, and others.
34 //
35 // Utility class for writing text to a ZeroCopyOutputStream.
36 
37 #ifndef GOOGLE_PROTOBUF_IO_PRINTER_H__
38 #define GOOGLE_PROTOBUF_IO_PRINTER_H__
39 
40 #include <string>
41 #include <map>
42 #include <vector>
43 #include <google/protobuf/stubs/common.h>
44 
45 namespace google {
46 namespace protobuf {
47 namespace io {
48 
49 class ZeroCopyOutputStream;     // zero_copy_stream.h
50 
51 // Records annotations about a Printer's output.
52 class LIBPROTOBUF_EXPORT AnnotationCollector {
53  public:
54   // Records that the bytes in file_path beginning with begin_offset and ending
55   // before end_offset are associated with the SourceCodeInfo-style path.
56   virtual void AddAnnotation(size_t begin_offset, size_t end_offset,
57                              const string& file_path,
58                              const vector<int>& path) = 0;
59 
~AnnotationCollector()60   virtual ~AnnotationCollector() {}
61 };
62 
63 // Records annotations about a Printer's output to the given protocol buffer,
64 // assuming that the buffer has an ::Annotation message exposing path,
65 // source_file, begin and end fields.
66 template <typename AnnotationProto>
67 class AnnotationProtoCollector : public AnnotationCollector {
68  public:
69   // annotation_proto is the protocol buffer to which new Annotations should be
70   // added. It is not owned by the AnnotationProtoCollector.
AnnotationProtoCollector(AnnotationProto * annotation_proto)71   explicit AnnotationProtoCollector(AnnotationProto* annotation_proto)
72       : annotation_proto_(annotation_proto) {}
73 
74   // Override for AnnotationCollector::AddAnnotation.
AddAnnotation(size_t begin_offset,size_t end_offset,const string & file_path,const vector<int> & path)75   virtual void AddAnnotation(size_t begin_offset, size_t end_offset,
76                              const string& file_path, const vector<int>& path) {
77     typename AnnotationProto::Annotation* annotation =
78         annotation_proto_->add_annotation();
79     for (int i = 0; i < path.size(); ++i) {
80       annotation->add_path(path[i]);
81     }
82     annotation->set_source_file(file_path);
83     annotation->set_begin(begin_offset);
84     annotation->set_end(end_offset);
85   }
86 
87  private:
88   // The protocol buffer to which new annotations should be added.
89   AnnotationProto* const annotation_proto_;
90 };
91 
92 // This simple utility class assists in code generation.  It basically
93 // allows the caller to define a set of variables and then output some
94 // text with variable substitutions.  Example usage:
95 //
96 //   Printer printer(output, '$');
97 //   map<string, string> vars;
98 //   vars["name"] = "Bob";
99 //   printer.Print(vars, "My name is $name$.");
100 //
101 // The above writes "My name is Bob." to the output stream.
102 //
103 // Printer aggressively enforces correct usage, crashing (with assert failures)
104 // in the case of undefined variables in debug builds. This helps greatly in
105 // debugging code which uses it.
106 //
107 // If a Printer is constructed with an AnnotationCollector, it will provide it
108 // with annotations that connect the Printer's output to paths that can identify
109 // various descriptors.  In the above example, if person_ is a descriptor that
110 // identifies Bob, we can associate the output string "My name is Bob." with
111 // a source path pointing to that descriptor with:
112 //
113 //   printer.Annotate("name", person_);
114 //
115 // The AnnotationCollector will be sent an annotation linking the output range
116 // covering "Bob" to the logical path provided by person_.  Tools may use
117 // this association to (for example) link "Bob" in the output back to the
118 // source file that defined the person_ descriptor identifying Bob.
119 //
120 // Annotate can only examine variables substituted during the last call to
121 // Print.  It is invalid to refer to a variable that was used multiple times
122 // in a single Print call.
123 //
124 // In full generality, one may specify a range of output text using a beginning
125 // substitution variable and an ending variable.  The resulting annotation will
126 // span from the first character of the substituted value for the beginning
127 // variable to the last character of the substituted value for the ending
128 // variable.  For example, the Annotate call above is equivalent to this one:
129 //
130 //   printer.Annotate("name", "name", person_);
131 //
132 // This is useful if multiple variables combine to form a single span of output
133 // that should be annotated with the same source path.  For example:
134 //
135 //   Printer printer(output, '$');
136 //   map<string, string> vars;
137 //   vars["first"] = "Alice";
138 //   vars["last"] = "Smith";
139 //   printer.Print(vars, "My name is $first$ $last$.");
140 //   printer.Annotate("first", "last", person_);
141 //
142 // This code would associate the span covering "Alice Smith" in the output with
143 // the person_ descriptor.
144 //
145 // Note that the beginning variable must come before (or overlap with, in the
146 // case of zero-sized substitution values) the ending variable.
147 //
148 // It is also sometimes useful to use variables with zero-sized values as
149 // markers.  This avoids issues with multiple references to the same variable
150 // and also allows annotation ranges to span literal text from the Print
151 // templates:
152 //
153 //   Printer printer(output, '$');
154 //   map<string, string> vars;
155 //   vars["foo"] = "bar";
156 //   vars["function"] = "call";
157 //   vars["mark"] = "";
158 //   printer.Print(vars, "$function$($foo$,$foo$)$mark$");
159 //   printer.Annotate("function", "rmark", call_);
160 //
161 // This code associates the span covering "call(bar,bar)" in the output with the
162 // call_ descriptor.
163 
164 class LIBPROTOBUF_EXPORT Printer {
165  public:
166   // Create a printer that writes text to the given output stream.  Use the
167   // given character as the delimiter for variables.
168   Printer(ZeroCopyOutputStream* output, char variable_delimiter);
169 
170   // Create a printer that writes text to the given output stream.  Use the
171   // given character as the delimiter for variables.  If annotation_collector
172   // is not null, Printer will provide it with annotations about code written
173   // to the stream.  annotation_collector is not owned by Printer.
174   Printer(ZeroCopyOutputStream* output, char variable_delimiter,
175           AnnotationCollector* annotation_collector);
176 
177   ~Printer();
178 
179   // Link a subsitution variable emitted by the last call to Print to the object
180   // described by descriptor.
181   template <typename SomeDescriptor>
Annotate(const char * varname,const SomeDescriptor * descriptor)182   void Annotate(const char* varname, const SomeDescriptor* descriptor) {
183     Annotate(varname, varname, descriptor);
184   }
185 
186   // Link the output range defined by the substitution variables as emitted by
187   // the last call to Print to the object described by descriptor. The range
188   // begins at begin_varname's value and ends after the last character of the
189   // value substituted for end_varname.
190   template <typename SomeDescriptor>
Annotate(const char * begin_varname,const char * end_varname,const SomeDescriptor * descriptor)191   void Annotate(const char* begin_varname, const char* end_varname,
192                 const SomeDescriptor* descriptor) {
193     if (annotation_collector_ == NULL) {
194       // Annotations aren't turned on for this Printer, so don't pay the cost
195       // of building the location path.
196       return;
197     }
198     vector<int> path;
199     descriptor->GetLocationPath(&path);
200     Annotate(begin_varname, end_varname, descriptor->file()->name(), path);
201   }
202 
203   // Link a subsitution variable emitted by the last call to Print to the file
204   // with path file_name.
Annotate(const char * varname,const string & file_name)205   void Annotate(const char* varname, const string& file_name) {
206     Annotate(varname, varname, file_name);
207   }
208 
209   // Link the output range defined by the substitution variables as emitted by
210   // the last call to Print to the file with path file_name. The range begins
211   // at begin_varname's value and ends after the last character of the value
212   // substituted for end_varname.
Annotate(const char * begin_varname,const char * end_varname,const string & file_name)213   void Annotate(const char* begin_varname, const char* end_varname,
214                 const string& file_name) {
215     if (annotation_collector_ == NULL) {
216       // Annotations aren't turned on for this Printer.
217       return;
218     }
219     vector<int> empty_path;
220     Annotate(begin_varname, end_varname, file_name, empty_path);
221   }
222 
223   // Print some text after applying variable substitutions.  If a particular
224   // variable in the text is not defined, this will crash.  Variables to be
225   // substituted are identified by their names surrounded by delimiter
226   // characters (as given to the constructor).  The variable bindings are
227   // defined by the given map.
228   void Print(const map<string, string>& variables, const char* text);
229 
230   // Like the first Print(), except the substitutions are given as parameters.
231   void Print(const char* text);
232   // Like the first Print(), except the substitutions are given as parameters.
233   void Print(const char* text, const char* variable, const string& value);
234   // Like the first Print(), except the substitutions are given as parameters.
235   void Print(const char* text, const char* variable1, const string& value1,
236                                const char* variable2, const string& value2);
237   // Like the first Print(), except the substitutions are given as parameters.
238   void Print(const char* text, const char* variable1, const string& value1,
239                                const char* variable2, const string& value2,
240                                const char* variable3, const string& value3);
241   // Like the first Print(), except the substitutions are given as parameters.
242   void Print(const char* text, const char* variable1, const string& value1,
243                                const char* variable2, const string& value2,
244                                const char* variable3, const string& value3,
245                                const char* variable4, const string& value4);
246   // Like the first Print(), except the substitutions are given as parameters.
247   void Print(const char* text, const char* variable1, const string& value1,
248                                const char* variable2, const string& value2,
249                                const char* variable3, const string& value3,
250                                const char* variable4, const string& value4,
251                                const char* variable5, const string& value5);
252   // Like the first Print(), except the substitutions are given as parameters.
253   void Print(const char* text, const char* variable1, const string& value1,
254                                const char* variable2, const string& value2,
255                                const char* variable3, const string& value3,
256                                const char* variable4, const string& value4,
257                                const char* variable5, const string& value5,
258                                const char* variable6, const string& value6);
259   // Like the first Print(), except the substitutions are given as parameters.
260   void Print(const char* text, const char* variable1, const string& value1,
261                                const char* variable2, const string& value2,
262                                const char* variable3, const string& value3,
263                                const char* variable4, const string& value4,
264                                const char* variable5, const string& value5,
265                                const char* variable6, const string& value6,
266                                const char* variable7, const string& value7);
267   // Like the first Print(), except the substitutions are given as parameters.
268   void Print(const char* text, const char* variable1, const string& value1,
269                                const char* variable2, const string& value2,
270                                const char* variable3, const string& value3,
271                                const char* variable4, const string& value4,
272                                const char* variable5, const string& value5,
273                                const char* variable6, const string& value6,
274                                const char* variable7, const string& value7,
275                                const char* variable8, const string& value8);
276 
277   // Indent text by two spaces.  After calling Indent(), two spaces will be
278   // inserted at the beginning of each line of text.  Indent() may be called
279   // multiple times to produce deeper indents.
280   void Indent();
281 
282   // Reduces the current indent level by two spaces, or crashes if the indent
283   // level is zero.
284   void Outdent();
285 
286   // Write a string to the output buffer.
287   // This method does not look for newlines to add indentation.
288   void PrintRaw(const string& data);
289 
290   // Write a zero-delimited string to output buffer.
291   // This method does not look for newlines to add indentation.
292   void PrintRaw(const char* data);
293 
294   // Write some bytes to the output buffer.
295   // This method does not look for newlines to add indentation.
296   void WriteRaw(const char* data, int size);
297 
298   // True if any write to the underlying stream failed.  (We don't just
299   // crash in this case because this is an I/O failure, not a programming
300   // error.)
failed()301   bool failed() const { return failed_; }
302 
303  private:
304   // Link the output range defined by the substitution variables as emitted by
305   // the last call to Print to the object found at the SourceCodeInfo-style path
306   // in a file with path file_path. The range begins at the start of
307   // begin_varname's value and ends after the last character of the value
308   // substituted for end_varname. Note that begin_varname and end_varname
309   // may refer to the same variable.
310   void Annotate(const char* begin_varname, const char* end_varname,
311                 const string& file_path, const vector<int>& path);
312 
313   const char variable_delimiter_;
314 
315   ZeroCopyOutputStream* const output_;
316   char* buffer_;
317   int buffer_size_;
318   // The current position, in bytes, in the output stream.  This is equivalent
319   // to the total number of bytes that have been written so far.  This value is
320   // used to calculate annotation ranges in the substitutions_ map below.
321   size_t offset_;
322 
323   string indent_;
324   bool at_start_of_line_;
325   bool failed_;
326 
327   // A map from variable name to [start, end) offsets in the output buffer.
328   // These refer to the offsets used for a variable after the last call to
329   // Print.  If a variable was used more than once, the entry used in
330   // this map is set to a negative-length span.  For singly-used variables, the
331   // start offset is the beginning of the substitution; the end offset is the
332   // last byte of the substitution plus one (such that (end - start) is the
333   // length of the substituted string).
334   map<string, pair<size_t, size_t> > substitutions_;
335 
336   // Returns true and sets range to the substitution range in the output for
337   // varname if varname was used once in the last call to Print. If varname
338   // was not used, or if it was used multiple times, returns false (and
339   // fails a debug assertion).
340   bool GetSubstitutionRange(const char* varname, pair<size_t, size_t>* range);
341 
342   // If non-null, annotation_collector_ is used to store annotations about
343   // generated code.
344   AnnotationCollector* const annotation_collector_;
345 
346   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Printer);
347 };
348 
349 }  // namespace io
350 }  // namespace protobuf
351 
352 }  // namespace google
353 #endif  // GOOGLE_PROTOBUF_IO_PRINTER_H__
354