diff options
Diffstat (limited to 'src/google/protobuf/io/printer.h')
-rw-r--r-- | src/google/protobuf/io/printer.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/src/google/protobuf/io/printer.h b/src/google/protobuf/io/printer.h index f1490bbe..2ba84559 100644 --- a/src/google/protobuf/io/printer.h +++ b/src/google/protobuf/io/printer.h @@ -39,6 +39,7 @@ #include <string> #include <map> +#include <vector> #include <google/protobuf/stubs/common.h> namespace google { @@ -47,6 +48,47 @@ namespace io { class ZeroCopyOutputStream; // zero_copy_stream.h +// Records annotations about a Printer's output. +class LIBPROTOBUF_EXPORT AnnotationCollector { + public: + // Records that the bytes in file_path beginning with begin_offset and ending + // before end_offset are associated with the SourceCodeInfo-style path. + virtual void AddAnnotation(size_t begin_offset, size_t end_offset, + const string& file_path, + const vector<int>& path) = 0; + + virtual ~AnnotationCollector() {} +}; + +// Records annotations about a Printer's output to the given protocol buffer, +// assuming that the buffer has an ::Annotation message exposing path, +// source_file, begin and end fields. +template <typename AnnotationProto> +class AnnotationProtoCollector : public AnnotationCollector { + public: + // annotation_proto is the protocol buffer to which new Annotations should be + // added. It is not owned by the AnnotationProtoCollector. + explicit AnnotationProtoCollector(AnnotationProto* annotation_proto) + : annotation_proto_(annotation_proto) {} + + // Override for AnnotationCollector::AddAnnotation. + virtual void AddAnnotation(size_t begin_offset, size_t end_offset, + const string& file_path, const vector<int>& path) { + typename AnnotationProto::Annotation* annotation = + annotation_proto_->add_annotation(); + for (int i = 0; i < path.size(); ++i) { + annotation->add_path(path[i]); + } + annotation->set_source_file(file_path); + annotation->set_begin(begin_offset); + annotation->set_end(end_offset); + } + + private: + // The protocol buffer to which new annotations should be added. + AnnotationProto* const annotation_proto_; +}; + // This simple utility class assists in code generation. It basically // allows the caller to define a set of variables and then output some // text with variable substitutions. Example usage: @@ -61,13 +103,103 @@ class ZeroCopyOutputStream; // zero_copy_stream.h // Printer aggressively enforces correct usage, crashing (with assert failures) // in the case of undefined variables in debug builds. This helps greatly in // debugging code which uses it. +// +// If a Printer is constructed with an AnnotationCollector, it will provide it +// with annotations that connect the Printer's output to paths that can identify +// various descriptors. In the above example, if person_ is a descriptor that +// identifies Bob, we can associate the output string "My name is Bob." with +// a source path pointing to that descriptor with: +// +// printer.Annotate("name", person_); +// +// The AnnotationCollector will be sent an annotation linking the output range +// covering "Bob" to the logical path provided by person_. Tools may use +// this association to (for example) link "Bob" in the output back to the +// source file that defined the person_ descriptor identifying Bob. +// +// Annotate can only examine variables substituted during the last call to +// Print. It is invalid to refer to a variable that was used multiple times +// in a single Print call. +// +// In full generality, one may specify a range of output text using a beginning +// substitution variable and an ending variable. The resulting annotation will +// span from the first character of the substituted value for the beginning +// variable to the last character of the substituted value for the ending +// variable. For example, the Annotate call above is equivalent to this one: +// +// printer.Annotate("name", "name", person_); +// +// This is useful if multiple variables combine to form a single span of output +// that should be annotated with the same source path. For example: +// +// Printer printer(output, '$'); +// map<string, string> vars; +// vars["first"] = "Alice"; +// vars["last"] = "Smith"; +// printer.Print(vars, "My name is $first$ $last$."); +// printer.Annotate("first", "last", person_); +// +// This code would associate the span covering "Alice Smith" in the output with +// the person_ descriptor. +// +// Note that the beginning variable must come before (or overlap with, in the +// case of zero-sized substitution values) the ending variable. +// +// It is also sometimes useful to use variables with zero-sized values as +// markers. This avoids issues with multiple references to the same variable +// and also allows annotation ranges to span literal text from the Print +// templates: +// +// Printer printer(output, '$'); +// map<string, string> vars; +// vars["foo"] = "bar"; +// vars["function"] = "call"; +// vars["mark"] = ""; +// printer.Print(vars, "$function$($foo$,$foo$)$mark$"); +// printer.Annotate("function", "rmark", call_); +// +// This code associates the span covering "call(bar,bar)" in the output with the +// call_ descriptor. + class LIBPROTOBUF_EXPORT Printer { public: // Create a printer that writes text to the given output stream. Use the // given character as the delimiter for variables. Printer(ZeroCopyOutputStream* output, char variable_delimiter); + + // Create a printer that writes text to the given output stream. Use the + // given character as the delimiter for variables. If annotation_collector + // is not null, Printer will provide it with annotations about code written + // to the stream. annotation_collector is not owned by Printer. + Printer(ZeroCopyOutputStream* output, char variable_delimiter, + AnnotationCollector* annotation_collector); + ~Printer(); + // Link a subsitution variable emitted by the last call to Print to the object + // described by descriptor. + template <typename SomeDescriptor> + void Annotate(const char* varname, const SomeDescriptor* descriptor) { + Annotate(varname, varname, descriptor); + } + + // Link the output range defined by the substitution variables as emitted by + // the last call to Print to the object described by descriptor. The range + // begins at begin_varname's value and ends after the last character of the + // value substituted for end_varname. + template <typename SomeDescriptor> + void Annotate(const char* begin_varname, const char* end_varname, + const SomeDescriptor* descriptor) { + if (annotation_collector_ == NULL) { + // Annotations aren't turned on for this Printer, so don't pay the cost + // of building the location path. + return; + } + vector<int> path; + descriptor->GetLocationPath(&path); + Annotate(begin_varname, end_varname, descriptor->file()->name(), path); + } + // Print some text after applying variable substitutions. If a particular // variable in the text is not defined, this will crash. Variables to be // substituted are identified by their names surrounded by delimiter @@ -149,16 +281,48 @@ class LIBPROTOBUF_EXPORT Printer { bool failed() const { return failed_; } private: + // Link the output range defined by the substitution variables as emitted by + // the last call to Print to the object found at the SourceCodeInfo-style path + // in a file with path file_path. The range begins at the start of + // begin_varname's value and ends after the last character of the value + // substituted for end_varname. Note that begin_varname and end_varname + // may refer to the same variable. + void Annotate(const char* begin_varname, const char* end_varname, + const string& file_path, const vector<int>& path); + const char variable_delimiter_; ZeroCopyOutputStream* const output_; char* buffer_; int buffer_size_; + // The current position, in bytes, in the output stream. This is equivalent + // to the total number of bytes that have been written so far. This value is + // used to calculate annotation ranges in the substitutions_ map below. + size_t offset_; string indent_; bool at_start_of_line_; bool failed_; + // A map from variable name to [start, end) offsets in the output buffer. + // These refer to the offsets used for a variable after the last call to + // Print. If a variable was used more than once, the entry used in + // this map is set to a negative-length span. For singly-used variables, the + // start offset is the beginning of the substitution; the end offset is the + // last byte of the substitution plus one (such that (end - start) is the + // length of the substituted string). + map<string, pair<size_t, size_t> > substitutions_; + + // Returns true and sets range to the substitution range in the output for + // varname if varname was used once in the last call to Print. If varname + // was not used, or if it was used multiple times, returns false (and + // fails a debug assertion). + bool GetSubstitutionRange(const char* varname, pair<size_t, size_t>* range); + + // If non-null, annotation_collector_ is used to store annotations about + // generated code. + AnnotationCollector* const annotation_collector_; + GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Printer); }; |