THUAI6/CAPI/cpp/grpc/include/google/protobuf/io/printer.h

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// 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 <map>
#include <string>
#include <vector>

#include <google/protobuf/stubs/common.h>

// Must be included last.
#include <google/protobuf/port_def.inc>

namespace google
{
    namespace protobuf
    {
        namespace io
        {

            class ZeroCopyOutputStream;  // zero_copy_stream.h

            // Records annotations about a Printer's output.
            class PROTOBUF_EXPORT AnnotationCollector
            {
            public:
                // Annotation is a offset range and a payload pair.
                typedef std::pair<std::pair<size_t, size_t>, std::string> Annotation;

                // 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 std::string& file_path, const std::vector<int>& path) = 0;

                // TODO(gerbens) I don't see why we need virtuals here. Just a vector of
                // range, payload pairs stored in a context should suffice.
                virtual void AddAnnotationNew(Annotation& /* a */)
                {
                }

                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.
                void AddAnnotation(size_t begin_offset, size_t end_offset, const std::string& file_path, const std::vector<int>& path) override
                {
                    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);
                }
                // Override for AnnotationCollector::AddAnnotation.
                void AddAnnotationNew(Annotation& a) override
                {
                    auto* annotation = annotation_proto_->add_annotation();
                    annotation->ParseFromString(a.second);
                    annotation->set_begin(a.first.first);
                    annotation->set_end(a.first.second);
                }

            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:
            //
            //   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 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", "mark", call_);
            //
            // This code associates the span covering "call(bar,bar)" in the output with the
            // call_ descriptor.

            class PROTOBUF_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 substitution 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;
                    }
                    std::vector<int> path;
                    descriptor->GetLocationPath(&path);
                    Annotate(begin_varname, end_varname, descriptor->file()->name(), path);
                }

                // Link a substitution variable emitted by the last call to Print to the file
                // with path file_name.
                void Annotate(const char* varname, const std::string& file_name)
                {
                    Annotate(varname, varname, file_name);
                }

                // Link the output range defined by the substitution variables as emitted by
                // the last call to Print to the file with path file_name. The range begins
                // at begin_varname's value and ends after the last character of the value
                // substituted for end_varname.
                void Annotate(const char* begin_varname, const char* end_varname, const std::string& file_name)
                {
                    if (annotation_collector_ == NULL)
                    {
                        // Annotations aren't turned on for this Printer.
                        return;
                    }
                    std::vector<int> empty_path;
                    Annotate(begin_varname, end_varname, file_name, empty_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
                // characters (as given to the constructor).  The variable bindings are
                // defined by the given map.
                void Print(const std::map<std::string, std::string>& variables, const char* text);

                // Like the first Print(), except the substitutions are given as parameters.
                template<typename... Args>
                void Print(const char* text, const Args&... args)
                {
                    std::map<std::string, std::string> vars;
                    PrintInternal(&vars, text, args...);
                }

                // 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();

                // Write a string to the output buffer.
                // This method does not look for newlines to add indentation.
                void PrintRaw(const std::string& data);

                // Write a zero-delimited string to output buffer.
                // This method does not look for newlines to add indentation.
                void PrintRaw(const char* data);

                // Write some bytes to the output buffer.
                // This method does not look for newlines to add indentation.
                void WriteRaw(const char* data, int size);

                // FormatInternal is a helper function not meant to use directly, use
                // compiler::cpp::Formatter instead. This function is meant to support
                // formatting text using named variables (eq. "$foo$) from a lookup map (vars)
                // and variables directly supplied by arguments (eq "$1$" meaning first
                // argument which is the zero index element of args).
                void FormatInternal(const std::vector<std::string>& args, const std::map<std::string, std::string>& vars, const char* format);

                // 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:
                // 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 std::string& file_path, const std::vector<int>& path);

                // Base case
                void PrintInternal(std::map<std::string, std::string>* vars, const char* text)
                {
                    Print(*vars, text);
                }

                template<typename... Args>
                void PrintInternal(std::map<std::string, std::string>* vars, const char* text, const char* key, const std::string& value, const Args&... args)
                {
                    (*vars)[key] = value;
                    PrintInternal(vars, text, args...);
                }

                // Copy size worth of bytes from data to buffer_.
                void CopyToBuffer(const char* data, int size);

                void push_back(char c)
                {
                    if (failed_)
                        return;
                    if (buffer_size_ == 0)
                    {
                        if (!Next())
                            return;
                    }
                    *buffer_++ = c;
                    buffer_size_--;
                    offset_++;
                }

                bool Next();

                inline void IndentIfAtStart();
                const char* WriteVariable(
                    const std::vector<std::string>& args,
                    const std::map<std::string, std::string>& vars,
                    const char* format,
                    int* arg_index,
                    std::vector<AnnotationCollector::Annotation>* annotations
                );

                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_;

                std::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).
                std::map<std::string, std::pair<size_t, size_t>> substitutions_;

                // Keeps track of the keys in substitutions_ that need to be updated when
                // indents are inserted. These are keys that refer to the beginning of the
                // current line.
                std::vector<std::string> line_start_variables_;

                // 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, std::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);
            };

        }  // namespace io
    }      // namespace protobuf
}  // namespace google

#include <google/protobuf/port_undef.inc>

#endif  // GOOGLE_PROTOBUF_IO_PRINTER_H__