src/google/protobuf/compiler/js/embed.cc

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
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//
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// in the documentation and/or other materials provided with the
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#include <cassert>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <string>

static bool AsciiIsPrint(unsigned char c) {
  return c >= 32 && c < 127;
}

static char ToDecimalDigit(int num) {
  assert(num < 10);
  return '0' + num;
}

static std::string CEscape(const std::string& str) {
  std::string dest;

  for (size_t i = 0; i < str.size(); ++i) {
    unsigned char ch = str[i];
    switch (ch) {
      case '\n': dest += "\\n"; break;
      case '\r': dest += "\\r"; break;
      case '\t': dest += "\\t"; break;
      case '\"': dest += "\\\""; break;
      case '\\': dest += "\\\\"; break;
      default:
        if (AsciiIsPrint(ch)) {
          dest += ch;
        } else {
          dest += "\\";
          dest += ToDecimalDigit(ch / 64);
          dest += ToDecimalDigit((ch % 64) / 8);
          dest += ToDecimalDigit(ch % 8);
        }
        break;
    }
  }

  return dest;
}

static void AddFile(const char* name, std::basic_ostream<char>* out) {
  std::ifstream in(name);

  if (!in.is_open()) {
    std::cerr << "Couldn't open input file: " << name << "\n";
    std::exit(EXIT_FAILURE);
  }

  // Make canonical name only include the final element.
  for (const char *p = name; *p; p++) {
    if (*p == '/') {
      name = p + 1;
    }
  }

  *out << "{\"" << CEscape(name) << "\",\n";

  for (std::string line; std::getline(in, line); ) {
    *out << "  \"" << CEscape(line) << "\\n\"\n";
  }

  *out << "},\n";
}

static void WriteOutput(char* file_names[], int num_file_names,
                        std::ostream* out) {
  *out << "#include "
          "\"google/protobuf/compiler/js/well_known_types_embed.h\"\n";
  *out << "struct FileToc well_known_types_js[] = {\n";

  for (int i = 0; i < num_file_names; i++) {
    AddFile(file_names[i], out);
  }

  *out << "  {NULL, NULL}  // Terminate the list.\n";
  *out << "};\n";
}

int main(int argc, char* argv[]) {
  // If argv[1] is the flag "--output_file" and argv[2] is the path to a file
  // that we can successfully open for output, then we write the output to
  // that file and interpret the remaining arguments as input file names.
  // Otherwise we interpret all arguments as input file names and write the
  // output to std out.
  std::ostream* out = &std::cout;
  std::ofstream ofs;
  char** file_names = (argc > 1 ? &argv[1] : nullptr);
  int num_file_names = argc - 1;
  if (argc > 2) {
    std::string arg1(argv[1]);
    if (arg1 == "--output_file") {
      // Try to open the file specified by argv[2]
      ofs.open(argv[2]);
      if (ofs.is_open()) {
        file_names = (argc > 3 ? &argv[3] : nullptr);
        num_file_names = argc - 3;
        out = &ofs;
      }
    }
  }
  WriteOutput(file_names, num_file_names, out);
  if (ofs.is_open()) {
    ofs.close();
  }
  return EXIT_SUCCESS;
}