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Diffstat (limited to 'src/google/protobuf/io/printer.h')
-rw-r--r-- | src/google/protobuf/io/printer.h | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/src/google/protobuf/io/printer.h b/src/google/protobuf/io/printer.h new file mode 100644 index 00000000..ee8f46c8 --- /dev/null +++ b/src/google/protobuf/io/printer.h @@ -0,0 +1,109 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. +// http://code.google.com/p/protobuf/ +// +// 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. + +// Author: kenton@google.com (Kenton Varda) +// Based on original Protocol Buffers design by +// Sanjay Ghemawat, Jeff Dean, and others. +// +// Utility class for writing text to a ZeroCopyOutputStream. + +#ifndef GOOGLE_PROTOBUF_IO_PRINTER_H__ +#define GOOGLE_PROTOBUF_IO_PRINTER_H__ + +#include <string> +#include <map> +#include <google/protobuf/stubs/common.h> + +namespace google { +namespace protobuf { +namespace io { + +class ZeroCopyOutputStream; // zero_copy_stream.h + +// 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: +// +// Printer printer(output, '$'); +// map<string, string> vars; +// vars["name"] = "Bob"; +// printer.Print(vars, "My name is $name$."); +// +// The above writes "My name is Bob." to the output stream. +// +// Printer aggressively enforces correct usage, crashing (with assert failures) +// in the case of undefined variables. This helps greatly in debugging code +// which uses it. This class is not intended to be used by production servers. +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); + ~Printer(); + + // 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 + // characters (as given to the constructor). The variable bindings are + // defined by the given map. + void Print(const map<string, string>& variables, const char* text); + + // Like the first Print(), except the substitutions are given as parameters. + void Print(const char* text); + // Like the first Print(), except the substitutions are given as parameters. + void Print(const char* text, const char* variable, const string& value); + // Like the first Print(), except the substitutions are given as parameters. + void Print(const char* text, const char* variable1, const string& value1, + const char* variable2, const string& value2); + // TODO(kenton): Overloaded versions with more variables? Two seems + // to be enough. + + // Indent text by two spaces. After calling Indent(), two spaces will be + // inserted at the beginning of each line of text. Indent() may be called + // multiple times to produce deeper indents. + void Indent(); + + // Reduces the current indent level by two spaces, or crashes if the indent + // level is zero. + void Outdent(); + + // True if any write to the underlying stream failed. (We don't just + // crash in this case because this is an I/O failure, not a programming + // error.) + bool failed() const { return failed_; } + + private: + // Write some text to the output buffer. + void Write(const char* data, int size); + + const char variable_delimiter_; + + ZeroCopyOutputStream* const output_; + char* buffer_; + int buffer_size_; + + string indent_; + bool at_start_of_line_; + bool failed_; + + GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Printer); +}; + +} // namespace io +} // namespace protobuf + +} // namespace google +#endif // GOOGLE_PROTOBUF_IO_PRINTER_H__ |