xref: /external/protobuf/src/google/protobuf/compiler/command_line_interface.cc

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// http://code.google.com/p/protobuf/
//
// 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.

#include <google/protobuf/compiler/command_line_interface.h>

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef _MSC_VER
#include <io.h>
#include <direct.h>
#else
#include <unistd.h>
#endif
#include <errno.h>
#include <iostream>
#include <ctype.h>

#include <google/protobuf/compiler/importer.h>
#include <google/protobuf/compiler/code_generator.h>
#include <google/protobuf/compiler/plugin.pb.h>
#include <google/protobuf/compiler/subprocess.h>
#include <google/protobuf/compiler/zip_writer.h>
#include <google/protobuf/descriptor.h>
#include <google/protobuf/text_format.h>
#include <google/protobuf/dynamic_message.h>
#include <google/protobuf/io/zero_copy_stream_impl.h>
#include <google/protobuf/io/printer.h>
#include <google/protobuf/stubs/common.h>
#include <google/protobuf/stubs/strutil.h>
#include <google/protobuf/stubs/substitute.h>
#include <google/protobuf/stubs/map-util.h>
#include <google/protobuf/stubs/stl_util-inl.h>
#include <google/protobuf/stubs/hash.h>


namespace google {
namespace protobuf {
namespace compiler {

#if defined(_WIN32)
#define mkdir(name, mode) mkdir(name)
#ifndef W_OK
#define W_OK 02  // not defined by MSVC for whatever reason
#endif
#ifndef F_OK
#define F_OK 00  // not defined by MSVC for whatever reason
#endif
#ifndef STDIN_FILENO
#define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
#define STDOUT_FILENO 1
#endif
#endif

#ifndef O_BINARY
#ifdef _O_BINARY
#define O_BINARY _O_BINARY
#else
#define O_BINARY 0     // If this isn't defined, the platform doesn't need it.
#endif
#endif

namespace {
#if defined(_WIN32) && !defined(__CYGWIN__)
static const char* kPathSeparator = ";";
#else
static const char* kPathSeparator = ":";
#endif

// Returns true if the text looks like a Windows-style absolute path, starting
// with a drive letter.  Example:  "C:\foo".  TODO(kenton):  Share this with
// copy in importer.cc?
static bool IsWindowsAbsolutePath(const string& text) {
#if defined(_WIN32) || defined(__CYGWIN__)
  return text.size() >= 3 && text[1] == ':' &&
         isalpha(text[0]) &&
         (text[2] == '/' || text[2] == '\\') &&
         text.find_last_of(':') == 1;
#else
  return false;
#endif
}

void SetFdToTextMode(int fd) {
#ifdef _WIN32
  if (_setmode(fd, _O_TEXT) == -1) {
    // This should never happen, I think.
    GOOGLE_LOG(WARNING) << "_setmode(" << fd << ", _O_TEXT): " << strerror(errno);
  }
#endif
  // (Text and binary are the same on non-Windows platforms.)
}

void SetFdToBinaryMode(int fd) {
#ifdef _WIN32
  if (_setmode(fd, _O_BINARY) == -1) {
    // This should never happen, I think.
    GOOGLE_LOG(WARNING) << "_setmode(" << fd << ", _O_BINARY): " << strerror(errno);
  }
#endif
  // (Text and binary are the same on non-Windows platforms.)
}

void AddTrailingSlash(string* path) {
  if (!path->empty() && path->at(path->size() - 1) != '/') {
    path->push_back('/');
  }
}

bool VerifyDirectoryExists(const string& path) {
  if (path.empty()) return true;

  if (access(path.c_str(), W_OK) == -1) {
    cerr << path << ": " << strerror(errno) << endl;
    return false;
  } else {
    return true;
  }
}

// Try to create the parent directory of the given file, creating the parent's
// parent if necessary, and so on.  The full file name is actually
// (prefix + filename), but we assume |prefix| already exists and only create
// directories listed in |filename|.
bool TryCreateParentDirectory(const string& prefix, const string& filename) {
  // Recursively create parent directories to the output file.
  vector<string> parts;
  SplitStringUsing(filename, "/", &parts);
  string path_so_far = prefix;
  for (int i = 0; i < parts.size() - 1; i++) {
    path_so_far += parts[i];
    if (mkdir(path_so_far.c_str(), 0777) != 0) {
      if (errno != EEXIST) {
        cerr << filename << ": while trying to create directory "
             << path_so_far << ": " << strerror(errno) << endl;
        return false;
      }
    }
    path_so_far += '/';
  }

  return true;
}

}  // namespace

// A MultiFileErrorCollector that prints errors to stderr.
class CommandLineInterface::ErrorPrinter : public MultiFileErrorCollector,
                                           public io::ErrorCollector {
 public:
  ErrorPrinter(ErrorFormat format) : format_(format) {}
  ~ErrorPrinter() {}

  // implements MultiFileErrorCollector ------------------------------
  void AddError(const string& filename, int line, int column,
                const string& message) {

    cerr << filename;

    // Users typically expect 1-based line/column numbers, so we add 1
    // to each here.
    if (line != -1) {
      // Allow for both GCC- and Visual-Studio-compatible output.
      switch (format_) {
        case CommandLineInterface::ERROR_FORMAT_GCC:
          cerr << ":" << (line + 1) << ":" << (column + 1);
          break;
        case CommandLineInterface::ERROR_FORMAT_MSVS:
          cerr << "(" << (line + 1) << ") : error in column=" << (column + 1);
          break;
      }
    }

    cerr << ": " << message << endl;
  }

  // implements io::ErrorCollector -----------------------------------
  void AddError(int line, int column, const string& message) {
    AddError("input", line, column, message);
  }

 private:
  const ErrorFormat format_;
};

// -------------------------------------------------------------------

// An OutputDirectory implementation that buffers files in memory, then dumps
// them all to disk on demand.
class CommandLineInterface::MemoryOutputDirectory : public OutputDirectory {
 public:
  MemoryOutputDirectory();
  ~MemoryOutputDirectory();

  // Write all files in the directory to disk at the given output location,
  // which must end in a '/'.
  bool WriteAllToDisk(const string& prefix);

  // Write the contents of this directory to a ZIP-format archive with the
  // given name.
  bool WriteAllToZip(const string& filename);

  // Add a boilerplate META-INF/MANIFEST.MF file as required by the Java JAR
  // format, unless one has already been written.
  void AddJarManifest();

  // implements OutputDirectory --------------------------------------
  io::ZeroCopyOutputStream* Open(const string& filename);
  io::ZeroCopyOutputStream* OpenForInsert(
      const string& filename, const string& insertion_point);

 private:
  friend class MemoryOutputStream;

  // map instead of hash_map so that files are written in order (good when
  // writing zips).
  map<string, string*> files_;
  bool had_error_;
};

class CommandLineInterface::MemoryOutputStream
    : public io::ZeroCopyOutputStream {
 public:
  MemoryOutputStream(MemoryOutputDirectory* directory, const string& filename);
  MemoryOutputStream(MemoryOutputDirectory* directory, const string& filename,
                     const string& insertion_point);
  virtual ~MemoryOutputStream();

  // implements ZeroCopyOutputStream ---------------------------------
  virtual bool Next(void** data, int* size) { return inner_->Next(data, size); }
  virtual void BackUp(int count)            {        inner_->BackUp(count);    }
  virtual int64 ByteCount() const           { return inner_->ByteCount();      }

 private:
  // Where to insert the string when it's done.
  MemoryOutputDirectory* directory_;
  string filename_;
  string insertion_point_;

  // The string we're building.
  string data_;

  // StringOutputStream writing to data_.
  scoped_ptr<io::StringOutputStream> inner_;
};

// -------------------------------------------------------------------

CommandLineInterface::MemoryOutputDirectory::MemoryOutputDirectory()
    : had_error_(false) {}

CommandLineInterface::MemoryOutputDirectory::~MemoryOutputDirectory() {
  STLDeleteValues(&files_);
}

bool CommandLineInterface::MemoryOutputDirectory::WriteAllToDisk(
    const string& prefix) {
  if (had_error_) {
    return false;
  }

  if (!VerifyDirectoryExists(prefix)) {
    return false;
  }

  for (map<string, string*>::const_iterator iter = files_.begin();
       iter != files_.end(); ++iter) {
    const string& relative_filename = iter->first;
    const char* data = iter->second->data();
    int size = iter->second->size();

    if (!TryCreateParentDirectory(prefix, relative_filename)) {
      return false;
    }
    string filename = prefix + relative_filename;

    // Create the output file.
    int file_descriptor;
    do {
      file_descriptor =
        open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0666);
    } while (file_descriptor < 0 && errno == EINTR);

    if (file_descriptor < 0) {
      int error = errno;
      cerr << filename << ": " << strerror(error);
      return false;
    }

    // Write the file.
    while (size > 0) {
      int write_result;
      do {
        write_result = write(file_descriptor, data, size);
      } while (write_result < 0 && errno == EINTR);

      if (write_result <= 0) {
        // Write error.

        // FIXME(kenton):  According to the man page, if write() returns zero,
        //   there was no error; write() simply did not write anything.  It's
        //   unclear under what circumstances this might happen, but presumably
        //   errno won't be set in this case.  I am confused as to how such an
        //   event should be handled.  For now I'm treating it as an error,
        //   since retrying seems like it could lead to an infinite loop.  I
        //   suspect this never actually happens anyway.

        if (write_result < 0) {
          int error = errno;
          cerr << filename << ": write: " << strerror(error);
        } else {
          cerr << filename << ": write() returned zero?" << endl;
        }
        return false;
      }

      data += write_result;
      size -= write_result;
    }

    if (close(file_descriptor) != 0) {
      int error = errno;
      cerr << filename << ": close: " << strerror(error);
      return false;
    }
  }

  return true;
}

bool CommandLineInterface::MemoryOutputDirectory::WriteAllToZip(
    const string& filename) {
  if (had_error_) {
    return false;
  }

  // Create the output file.
  int file_descriptor;
  do {
    file_descriptor =
      open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0666);
  } while (file_descriptor < 0 && errno == EINTR);

  if (file_descriptor < 0) {
    int error = errno;
    cerr << filename << ": " << strerror(error);
    return false;
  }

  // Create the ZipWriter
  io::FileOutputStream stream(file_descriptor);
  ZipWriter zip_writer(&stream);

  for (map<string, string*>::const_iterator iter = files_.begin();
       iter != files_.end(); ++iter) {
    zip_writer.Write(iter->first, *iter->second);
  }

  zip_writer.WriteDirectory();

  if (stream.GetErrno() != 0) {
    cerr << filename << ": " << strerror(stream.GetErrno()) << endl;
  }

  if (!stream.Close()) {
    cerr << filename << ": " << strerror(stream.GetErrno()) << endl;
  }

  return true;
}

void CommandLineInterface::MemoryOutputDirectory::AddJarManifest() {
  string** map_slot = &files_["META-INF/MANIFEST.MF"];
  if (*map_slot == NULL) {
    *map_slot = new string(
        "Manifest-Version: 1.0\n"
        "Created-By: 1.6.0 (protoc)\n"
        "\n");
  }
}

io::ZeroCopyOutputStream* CommandLineInterface::MemoryOutputDirectory::Open(
    const string& filename) {
  return new MemoryOutputStream(this, filename);
}

io::ZeroCopyOutputStream*
CommandLineInterface::MemoryOutputDirectory::OpenForInsert(
    const string& filename, const string& insertion_point) {
  return new MemoryOutputStream(this, filename, insertion_point);
}

// -------------------------------------------------------------------

CommandLineInterface::MemoryOutputStream::MemoryOutputStream(
    MemoryOutputDirectory* directory, const string& filename)
    : directory_(directory),
      filename_(filename),
      inner_(new io::StringOutputStream(&data_)) {
}

CommandLineInterface::MemoryOutputStream::MemoryOutputStream(
    MemoryOutputDirectory* directory, const string& filename,
    const string& insertion_point)
    : directory_(directory),
      filename_(filename),
      insertion_point_(insertion_point),
      inner_(new io::StringOutputStream(&data_)) {
}

CommandLineInterface::MemoryOutputStream::~MemoryOutputStream() {
  // Make sure all data has been written.
  inner_.reset();

  // Insert into the directory.
  string** map_slot = &directory_->files_[filename_];

  if (insertion_point_.empty()) {
    // This was just a regular Open().
    if (*map_slot != NULL) {
      cerr << filename_ << ": Tried to write the same file twice." << endl;
      directory_->had_error_ = true;
      return;
    }

    *map_slot = new string;
    (*map_slot)->swap(data_);
  } else {
    // This was an OpenForInsert().

    // If the data doens't end with a clean line break, add one.
    if (!data_.empty() && data_[data_.size() - 1] != '\n') {
      data_.push_back('\n');
    }

    // Find the file we are going to insert into.
    if (*map_slot == NULL) {
      cerr << filename_ << ": Tried to insert into file that doesn't exist."
           << endl;
      directory_->had_error_ = true;
      return;
    }
    string* target = *map_slot;

    // Find the insertion point.
    string magic_string = strings::Substitute(
        "@@protoc_insertion_point($0)", insertion_point_);
    string::size_type pos = target->find(magic_string);

    if (pos == string::npos) {
      cerr << filename_ << ": insertion point \"" << insertion_point_
           << "\" not found." << endl;
      directory_->had_error_ = true;
      return;
    }

    // Seek backwards to the beginning of the line, which is where we will
    // insert the data.  Note that this has the effect of pushing the insertion
    // point down, so the data is inserted before it.  This is intentional
    // because it means that multiple insertions at the same point will end
    // up in the expected order in the final output.
    pos = target->find_last_of('\n', pos);
    if (pos == string::npos) {
      // Insertion point is on the first line.
      pos = 0;
    } else {
      // Advance to character after '\n'.
      ++pos;
    }

    // Extract indent.
    string indent_(*target, pos, target->find_first_not_of(" \t", pos) - pos);

    if (indent_.empty()) {
      // No indent.  This makes things easier.
      target->insert(pos, data_);
    } else {
      // Calculate how much space we need.
      int indent_size = 0;
      for (int i = 0; i < data_.size(); i++) {
        if (data_[i] == '\n') indent_size += indent_.size();
      }

      // Make a hole for it.
      target->insert(pos, data_.size() + indent_size, '\0');

      // Now copy in the data.
      string::size_type data_pos = 0;
      char* target_ptr = string_as_array(target) + pos;
      while (data_pos < data_.size()) {
        // Copy indent.
        memcpy(target_ptr, indent_.data(), indent_.size());
        target_ptr += indent_.size();

        // Copy line from data_.
        // We already guaranteed that data_ ends with a newline (above), so this
        // search can't fail.
        string::size_type line_length =
            data_.find_first_of('\n', data_pos) + 1 - data_pos;
        memcpy(target_ptr, data_.data() + data_pos, line_length);
        target_ptr += line_length;
        data_pos += line_length;
      }

      GOOGLE_CHECK_EQ(target_ptr,
          string_as_array(target) + pos + data_.size() + indent_size);
    }
  }
}

// ===================================================================

CommandLineInterface::CommandLineInterface()
  : mode_(MODE_COMPILE),
    error_format_(ERROR_FORMAT_GCC),
    imports_in_descriptor_set_(false),
    disallow_services_(false),
    inputs_are_proto_path_relative_(false) {}
CommandLineInterface::~CommandLineInterface() {}

void CommandLineInterface::RegisterGenerator(const string& flag_name,
                                             CodeGenerator* generator,
                                             const string& help_text) {
  GeneratorInfo info;
  info.generator = generator;
  info.help_text = help_text;
  generators_[flag_name] = info;
}

void CommandLineInterface::AllowPlugins(const string& exe_name_prefix) {
  plugin_prefix_ = exe_name_prefix;
}

int CommandLineInterface::Run(int argc, const char* const argv[]) {
  Clear();
  if (!ParseArguments(argc, argv)) return 1;

  // Set up the source tree.
  DiskSourceTree source_tree;
  for (int i = 0; i < proto_path_.size(); i++) {
    source_tree.MapPath(proto_path_[i].first, proto_path_[i].second);
  }

  // Map input files to virtual paths if necessary.
  if (!inputs_are_proto_path_relative_) {
    if (!MakeInputsBeProtoPathRelative(&source_tree)) {
      return 1;
    }
  }

  // Allocate the Importer.
  ErrorPrinter error_collector(error_format_);
  Importer importer(&source_tree, &error_collector);

  vector<const FileDescriptor*> parsed_files;

  // Parse each file.
  for (int i = 0; i < input_files_.size(); i++) {
    // Import the file.
    const FileDescriptor* parsed_file = importer.Import(input_files_[i]);
    if (parsed_file == NULL) return 1;
    parsed_files.push_back(parsed_file);

    // Enforce --disallow_services.
    if (disallow_services_ && parsed_file->service_count() > 0) {
      cerr << parsed_file->name() << ": This file contains services, but "
              "--disallow_services was used." << endl;
      return 1;
    }
  }

  // We construct a separate OutputDirectory for each output location.  Note
  // that two code generators may output to the same location, in which case
  // they should share a single OutputDirectory (so that OpenForInsert() works).
  typedef hash_map<string, MemoryOutputDirectory*> OutputDirectoryMap;
  OutputDirectoryMap output_directories;

  // Generate output.
  if (mode_ == MODE_COMPILE) {
    for (int i = 0; i < output_directives_.size(); i++) {
      string output_location = output_directives_[i].output_location;
      if (!HasSuffixString(output_location, ".zip") &&
          !HasSuffixString(output_location, ".jar")) {
        AddTrailingSlash(&output_location);
      }
      MemoryOutputDirectory** map_slot = &output_directories[output_location];

      if (*map_slot == NULL) {
        // First time we've seen this output location.
        *map_slot = new MemoryOutputDirectory;
      }

      if (!GenerateOutput(parsed_files, output_directives_[i], *map_slot)) {
        STLDeleteValues(&output_directories);
        return 1;
      }
    }
  }

  // Write all output to disk.
  for (OutputDirectoryMap::iterator iter = output_directories.begin();
       iter != output_directories.end(); ++iter) {
    const string& location = iter->first;
    MemoryOutputDirectory* directory = iter->second;
    if (HasSuffixString(location, "/")) {
      if (!directory->WriteAllToDisk(location)) {
        STLDeleteValues(&output_directories);
        return 1;
      }
    } else {
      if (HasSuffixString(location, ".jar")) {
        directory->AddJarManifest();
      }

      if (!directory->WriteAllToZip(location)) {
        STLDeleteValues(&output_directories);
        return 1;
      }
    }
  }

  STLDeleteValues(&output_directories);

  if (!descriptor_set_name_.empty()) {
    if (!WriteDescriptorSet(parsed_files)) {
      return 1;
    }
  }

  if (mode_ == MODE_ENCODE || mode_ == MODE_DECODE) {
    if (codec_type_.empty()) {
      // HACK:  Define an EmptyMessage type to use for decoding.
      DescriptorPool pool;
      FileDescriptorProto file;
      file.set_name("empty_message.proto");
      file.add_message_type()->set_name("EmptyMessage");
      GOOGLE_CHECK(pool.BuildFile(file) != NULL);
      codec_type_ = "EmptyMessage";
      if (!EncodeOrDecode(&pool)) {
        return 1;
      }
    } else {
      if (!EncodeOrDecode(importer.pool())) {
        return 1;
      }
    }
  }

  return 0;
}

void CommandLineInterface::Clear() {
  // Clear all members that are set by Run().  Note that we must not clear
  // members which are set by other methods before Run() is called.
  executable_name_.clear();
  proto_path_.clear();
  input_files_.clear();
  output_directives_.clear();
  codec_type_.clear();
  descriptor_set_name_.clear();

  mode_ = MODE_COMPILE;
  imports_in_descriptor_set_ = false;
  disallow_services_ = false;
}

bool CommandLineInterface::MakeInputsBeProtoPathRelative(
    DiskSourceTree* source_tree) {
  for (int i = 0; i < input_files_.size(); i++) {
    string virtual_file, shadowing_disk_file;
    switch (source_tree->DiskFileToVirtualFile(
        input_files_[i], &virtual_file, &shadowing_disk_file)) {
      case DiskSourceTree::SUCCESS:
        input_files_[i] = virtual_file;
        break;
      case DiskSourceTree::SHADOWED:
        cerr << input_files_[i] << ": Input is shadowed in the --proto_path "
                "by \"" << shadowing_disk_file << "\".  Either use the latter "
                "file as your input or reorder the --proto_path so that the "
                "former file's location comes first." << endl;
        return false;
      case DiskSourceTree::CANNOT_OPEN:
        cerr << input_files_[i] << ": " << strerror(errno) << endl;
        return false;
      case DiskSourceTree::NO_MAPPING:
        // First check if the file exists at all.
        if (access(input_files_[i].c_str(), F_OK) < 0) {
          // File does not even exist.
          cerr << input_files_[i] << ": " << strerror(ENOENT) << endl;
        } else {
          cerr << input_files_[i] << ": File does not reside within any path "
                  "specified using --proto_path (or -I).  You must specify a "
                  "--proto_path which encompasses this file.  Note that the "
                  "proto_path must be an exact prefix of the .proto file "
                  "names -- protoc is too dumb to figure out when two paths "
                  "(e.g. absolute and relative) are equivalent (it's harder "
                  "than you think)." << endl;
        }
        return false;
    }
  }

  return true;
}

bool CommandLineInterface::ParseArguments(int argc, const char* const argv[]) {
  executable_name_ = argv[0];

  // Iterate through all arguments and parse them.
  for (int i = 1; i < argc; i++) {
    string name, value;

    if (ParseArgument(argv[i], &name, &value)) {
      // Returned true => Use the next argument as the flag value.
      if (i + 1 == argc || argv[i+1][0] == '-') {
        cerr << "Missing value for flag: " << name << endl;
        if (name == "--decode") {
          cerr << "To decode an unknown message, use --decode_raw." << endl;
        }
        return false;
      } else {
        ++i;
        value = argv[i];
      }
    }

    if (!InterpretArgument(name, value)) return false;
  }

  // If no --proto_path was given, use the current working directory.
  if (proto_path_.empty()) {
    proto_path_.push_back(make_pair("", "."));
  }

  // Check some errror cases.
  bool decoding_raw = (mode_ == MODE_DECODE) && codec_type_.empty();
  if (decoding_raw && !input_files_.empty()) {
    cerr << "When using --decode_raw, no input files should be given." << endl;
    return false;
  } else if (!decoding_raw && input_files_.empty()) {
    cerr << "Missing input file." << endl;
    return false;
  }
  if (mode_ == MODE_COMPILE && output_directives_.empty() &&
      descriptor_set_name_.empty()) {
    cerr << "Missing output directives." << endl;
    return false;
  }
  if (imports_in_descriptor_set_ && descriptor_set_name_.empty()) {
    cerr << "--include_imports only makes sense when combined with "
            "--descriptor_set_out." << endl;
  }

  return true;
}

bool CommandLineInterface::ParseArgument(const char* arg,
                                         string* name, string* value) {
  bool parsed_value = false;

  if (arg[0] != '-') {
    // Not a flag.
    name->clear();
    parsed_value = true;
    *value = arg;
  } else if (arg[1] == '-') {
    // Two dashes:  Multi-character name, with '=' separating name and
    //   value.
    const char* equals_pos = strchr(arg, '=');
    if (equals_pos != NULL) {
      *name = string(arg, equals_pos - arg);
      *value = equals_pos + 1;
      parsed_value = true;
    } else {
      *name = arg;
    }
  } else {
    // One dash:  One-character name, all subsequent characters are the
    //   value.
    if (arg[1] == '\0') {
      // arg is just "-".  We treat this as an input file, except that at
      // present this will just lead to a "file not found" error.
      name->clear();
      *value = arg;
      parsed_value = true;
    } else {
      *name = string(arg, 2);
      *value = arg + 2;
      parsed_value = !value->empty();
    }
  }

  // Need to return true iff the next arg should be used as the value for this
  // one, false otherwise.

  if (parsed_value) {
    // We already parsed a value for this flag.
    return false;
  }

  if (*name == "-h" || *name == "--help" ||
      *name == "--disallow_services" ||
      *name == "--include_imports" ||
      *name == "--version" ||
      *name == "--decode_raw") {
    // HACK:  These are the only flags that don't take a value.
    //   They probably should not be hard-coded like this but for now it's
    //   not worth doing better.
    return false;
  }

  // Next argument is the flag value.
  return true;
}

bool CommandLineInterface::InterpretArgument(const string& name,
                                             const string& value) {
  if (name.empty()) {
    // Not a flag.  Just a filename.
    if (value.empty()) {
      cerr << "You seem to have passed an empty string as one of the "
              "arguments to " << executable_name_ << ".  This is actually "
              "sort of hard to do.  Congrats.  Unfortunately it is not valid "
              "input so the program is going to die now." << endl;
      return false;
    }

    input_files_.push_back(value);

  } else if (name == "-I" || name == "--proto_path") {
    // Java's -classpath (and some other languages) delimits path components
    // with colons.  Let's accept that syntax too just to make things more
    // intuitive.
    vector<string> parts;
    SplitStringUsing(value, kPathSeparator, &parts);

    for (int i = 0; i < parts.size(); i++) {
      string virtual_path;
      string disk_path;

      int equals_pos = parts[i].find_first_of('=');
      if (equals_pos == string::npos) {
        virtual_path = "";
        disk_path = parts[i];
      } else {
        virtual_path = parts[i].substr(0, equals_pos);
        disk_path = parts[i].substr(equals_pos + 1);
      }

      if (disk_path.empty()) {
        cerr << "--proto_path passed empty directory name.  (Use \".\" for "
                "current directory.)" << endl;
        return false;
      }

      // Make sure disk path exists, warn otherwise.
      if (access(disk_path.c_str(), F_OK) < 0) {
        cerr << disk_path << ": warning: directory does not exist." << endl;
      }

      proto_path_.push_back(make_pair(virtual_path, disk_path));
    }

  } else if (name == "-o" || name == "--descriptor_set_out") {
    if (!descriptor_set_name_.empty()) {
      cerr << name << " may only be passed once." << endl;
      return false;
    }
    if (value.empty()) {
      cerr << name << " requires a non-empty value." << endl;