tools/gn/command_args.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7
   8 #include <map>
   9
  10 #include "base/command_line.h"
  11 #include "base/environment.h"
  12 #include "base/files/file_util.h"
  13 #include "base/process/launch.h"
  14 #include "base/strings/string_number_conversions.h"
  15 #include "base/strings/string_util.h"
  16 #include "tools/gn/commands.h"
  17 #include "tools/gn/filesystem_utils.h"
  18 #include "tools/gn/input_file.h"
  19 #include "tools/gn/parse_tree.h"
  20 #include "tools/gn/setup.h"
  21 #include "tools/gn/standard_out.h"
  22 #include "tools/gn/tokenizer.h"
  23 #include "tools/gn/trace.h"
  24
  25 #if defined(OS_WIN)
  26 #include <windows.h>
  27 #include <shellapi.h>
  28 #endif
  29
  30 namespace commands {
  31
  32 namespace {
  33
  34 const char kSwitchList[] = "list";
  35 const char kSwitchShort[] = "short";
  36
  37 bool DoesLineBeginWithComment(const base::StringPiece& line) {
  38   // Skip whitespace.
  39   size_t i = 0;
  40   while (i < line.size() && base::IsAsciiWhitespace(line[i]))
  41     i++;
  42
  43   return i < line.size() && line[i] == '#';
  44 }
  45
  46 // Returns the offset of the beginning of the line identified by |offset|.
  47 size_t BackUpToLineBegin(const std::string& data, size_t offset) {
  48   // Degenerate case of an empty line. Below we'll try to return the
  49   // character after the newline, but that will be incorrect in this case.
  50   if (offset == 0 || Tokenizer::IsNewline(data, offset))
  51     return offset;
  52
  53   size_t cur = offset;
  54   do {
  55     cur --;
  56     if (Tokenizer::IsNewline(data, cur))
  57       return cur + 1;  // Want the first character *after* the newline.
  58   } while (cur > 0);
  59   return 0;
  60 }
  61
  62 // Assumes DoesLineBeginWithComment(), this strips the # character from the
  63 // beginning and normalizes preceeding whitespace.
  64 std::string StripHashFromLine(const base::StringPiece& line) {
  65   // Replace the # sign and everything before it with 3 spaces, so that a
  66   // normal comment that has a space after the # will be indented 4 spaces
  67   // (which makes our formatting come out nicely). If the comment is indented
  68   // from there, we want to preserve that indenting.
  69   return "   " + line.substr(line.find('#') + 1).as_string();
  70 }
  71
  72 // Tries to find the comment before the setting of the given value.
  73 void GetContextForValue(const Value& value,
  74                         std::string* location_str,
  75                         std::string* comment) {
  76   Location location = value.origin()->GetRange().begin();
  77   const InputFile* file = location.file();
  78   if (!file)
  79     return;
  80
  81   *location_str = file->name().value() + ":" +
  82       base::IntToString(location.line_number());
  83
  84   const std::string& data = file->contents();
  85   size_t line_off =
  86       Tokenizer::ByteOffsetOfNthLine(data, location.line_number());
  87
  88   while (line_off > 1) {
  89     line_off -= 2;  // Back up to end of previous line.
  90     size_t previous_line_offset = BackUpToLineBegin(data, line_off);
  91
  92     base::StringPiece line(&data[previous_line_offset],
  93                            line_off - previous_line_offset + 1);
  94     if (!DoesLineBeginWithComment(line))
  95       break;
  96
  97     comment->insert(0, StripHashFromLine(line) + "\n");
  98     line_off = previous_line_offset;
  99   }
 100 }
 101
 102 void PrintArgHelp(const base::StringPiece& name, const Value& value) {
 103   OutputString(name.as_string(), DECORATION_YELLOW);
 104   OutputString("  Default = " + value.ToString(true) + "\n");
 105
 106   if (value.origin()) {
 107     std::string location, comment;
 108     GetContextForValue(value, &location, &comment);
 109     OutputString("    " + location + "\n" + comment);
 110   } else {
 111     OutputString("    (Internally set)\n");
 112   }
 113 }
 114
 115 int ListArgs(const std::string& build_dir) {
 116   Setup* setup = new Setup;
 117   setup->build_settings().set_check_for_bad_items(false);
 118   if (!setup->DoSetup(build_dir, false) || !setup->Run())
 119     return 1;
 120
 121   Scope::KeyValueMap build_args;
 122   setup->build_settings().build_args().MergeDeclaredArguments(&build_args);
 123
 124   // Find all of the arguments we care about. Use a regular map so they're
 125   // sorted nicely when we write them out.
 126   std::map<base::StringPiece, Value> sorted_args;
 127   std::string list_value =
 128       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(kSwitchList);
 129   if (list_value.empty()) {
 130     // List all values.
 131     for (const auto& arg : build_args)
 132       sorted_args.insert(arg);
 133   } else {
 134     // List just the one specified as the parameter to --list.
 135     Scope::KeyValueMap::const_iterator found_arg = build_args.find(list_value);
 136     if (found_arg == build_args.end()) {
 137       Err(Location(), "Unknown build argument.",
 138           "You asked for \"" + list_value + "\" which I didn't find in any "
 139           "build file\nassociated with this build.").PrintToStdout();
 140       return 1;
 141     }
 142     sorted_args.insert(*found_arg);
 143   }
 144
 145   if (base::CommandLine::ForCurrentProcess()->HasSwitch(kSwitchShort)) {
 146     // Short key=value output.
 147     for (const auto& arg : sorted_args) {
 148       OutputString(arg.first.as_string());
 149       OutputString(" = ");
 150       OutputString(arg.second.ToString(true));
 151       OutputString("\n");
 152     }
 153     return 0;
 154   }
 155
 156   // Long output.
 157   for (const auto& arg : sorted_args) {
 158     PrintArgHelp(arg.first, arg.second);
 159     OutputString("\n");
 160   }
 161
 162   return 0;
 163 }
 164
 165 #if defined(OS_WIN)
 166
 167 bool RunEditor(const base::FilePath& file_to_edit) {
 168   SHELLEXECUTEINFO info;
 169   memset(&info, 0, sizeof(info));
 170   info.cbSize = sizeof(info);
 171   info.fMask = SEE_MASK_NOCLOSEPROCESS | SEE_MASK_CLASSNAME;
 172   info.lpFile = file_to_edit.value().c_str();
 173   info.nShow = SW_SHOW;
 174   info.lpClass = L".txt";
 175   if (!::ShellExecuteEx(&info)) {
 176     Err(Location(), "Couldn't run editor.",
 177         "Just edit \"" + FilePathToUTF8(file_to_edit) +
 178         "\" manually instead.").PrintToStdout();
 179     return false;
 180   }
 181
 182   if (!info.hProcess) {
 183     // Windows re-used an existing process.
 184     OutputString("\"" + FilePathToUTF8(file_to_edit) +
 185                  "\" opened in editor, save it and press <Enter> when done.\n");
 186     getchar();
 187   } else {
 188     OutputString("Waiting for editor on \"" + FilePathToUTF8(file_to_edit) +
 189                  "\"...\n");
 190     ::WaitForSingleObject(info.hProcess, INFINITE);
 191     ::CloseHandle(info.hProcess);
 192   }
 193   return true;
 194 }
 195
 196 #else  // POSIX
 197
 198 bool RunEditor(const base::FilePath& file_to_edit) {
 199   const char* editor_ptr = getenv("VISUAL");
 200   if (!editor_ptr)
 201     editor_ptr = getenv("GN_EDITOR");
 202   if (!editor_ptr)
 203     editor_ptr = getenv("EDITOR");
 204   if (!editor_ptr)
 205     editor_ptr = "vi";
 206
 207   std::string cmd(editor_ptr);
 208   cmd.append(" \"");
 209
 210   // Its impossible to do this properly since we don't know the user's shell,
 211   // but quoting and escaping internal quotes should handle 99.999% of all
 212   // cases.
 213   std::string escaped_name = file_to_edit.value();
 214   base::ReplaceSubstringsAfterOffset(&escaped_name, 0, "\"", "\\\"");
 215   cmd.append(escaped_name);
 216   cmd.push_back('"');
 217
 218   OutputString("Waiting for editor on \"" + file_to_edit.value() +
 219                "\"...\n");
 220   return system(cmd.c_str()) == 0;
 221 }
 222
 223 #endif
 224
 225 int EditArgsFile(const std::string& build_dir) {
 226   {
 227     // Scope the setup. We only use it for some basic state. We'll do the
 228     // "real" build below in the gen command.
 229     Setup setup;
 230     setup.build_settings().set_check_for_bad_items(false);
 231     // Don't fill build arguments. We're about to edit the file which supplies
 232     // these in the first place.
 233     setup.set_fill_arguments(false);
 234     if (!setup.DoSetup(build_dir, true))
 235       return 1;
 236
 237     // Ensure the file exists. Need to normalize path separators since on
 238     // Windows they can come out as forward slashes here, and that confuses some
 239     // of the commands.
 240     base::FilePath arg_file =
 241         setup.build_settings().GetFullPath(setup.GetBuildArgFile())
 242         .NormalizePathSeparators();
 243     if (!base::PathExists(arg_file)) {
 244       std::string argfile_default_contents =
 245           "# Build arguments go here. Examples:\n"
 246           "#   is_component_build = true\n"
 247           "#   is_debug = false\n"
 248           "# See \"gn args <out_dir> --list\" for available build "
 249           "arguments.\n";
 250 #if defined(OS_WIN)
 251       // Use Windows lineendings for this file since it will often open in
 252       // Notepad which can't handle Unix ones.
 253       base::ReplaceSubstringsAfterOffset(
 254           &argfile_default_contents, 0, "\n", "\r\n");
 255 #endif
 256       base::CreateDirectory(arg_file.DirName());
 257       base::WriteFile(arg_file, argfile_default_contents.c_str(),
 258                       static_cast<int>(argfile_default_contents.size()));
 259     }
 260
 261     ScopedTrace editor_trace(TraceItem::TRACE_SETUP, "Waiting for editor");
 262     if (!RunEditor(arg_file))
 263       return 1;
 264   }
 265
 266   // Now do a normal "gen" command.
 267   OutputString("Generating files...\n");
 268   std::vector<std::string> gen_commands;
 269   gen_commands.push_back(build_dir);
 270   return RunGen(gen_commands);
 271 }
 272
 273 }  // namespace
 274
 275 extern const char kArgs[] = "args";
 276 extern const char kArgs_HelpShort[] =
 277     "args: Display or configure arguments declared by the build.";
 278 extern const char kArgs_Help[] =
 279     "gn args <out_dir> [--list] [--short] [--args]\n"
 280     "\n"
 281     "  See also \"gn help buildargs\" for a more high-level overview of how\n"
 282     "  build arguments work.\n"
 283     "\n"
 284     "Usage\n"
 285     "  gn args <out_dir>\n"
 286     "      Open the arguments for the given build directory in an editor\n"
 287     "      (as specified by the EDITOR environment variable). If the given\n"
 288     "      build directory doesn't exist, it will be created and an empty\n"
 289     "      args file will be opened in the editor. You would type something\n"
 290     "      like this into that file:\n"
 291     "          enable_doom_melon=false\n"
 292     "          os=\"android\"\n"
 293     "\n"
 294     "      Note: you can edit the build args manually by editing the file\n"
 295     "      \"args.gn\" in the build directory and then running\n"
 296     "      \"gn gen <out_dir>\".\n"
 297     "\n"
 298     "  gn args <out_dir> --list[=<exact_arg>] [--short]\n"
 299     "      Lists all build arguments available in the current configuration,\n"
 300     "      or, if an exact_arg is specified for the list flag, just that one\n"
 301     "      build argument.\n"
 302     "\n"
 303     "      The output will list the declaration location, default value, and\n"
 304     "      comment preceeding the declaration. If --short is specified,\n"
 305     "      only the names and values will be printed.\n"
 306     "\n"
 307     "      If the out_dir is specified, the build configuration will be\n"
 308     "      taken from that build directory. The reason this is needed is that\n"
 309     "      the definition of some arguments is dependent on the build\n"
 310     "      configuration, so setting some values might add, remove, or change\n"
 311     "      the default values for other arguments. Specifying your exact\n"
 312     "      configuration allows the proper arguments to be displayed.\n"
 313     "\n"
 314     "      Instead of specifying the out_dir, you can also use the\n"
 315     "      command-line flag to specify the build configuration:\n"
 316     "        --args=<exact list of args to use>\n"
 317     "\n"
 318     "Examples\n"
 319     "  gn args out/Debug\n"
 320     "    Opens an editor with the args for out/Debug.\n"
 321     "\n"
 322     "  gn args out/Debug --list --short\n"
 323     "    Prints all arguments with their default values for the out/Debug\n"
 324     "    build.\n"
 325     "\n"
 326     "  gn args out/Debug --list=target_cpu\n"
 327     "    Prints information about the \"target_cpu\" argument for the "
 328         "out/Debug\n"
 329     "    build.\n"
 330     "\n"
 331     "  gn args --list --args=\"os=\\\"android\\\" enable_doom_melon=true\"\n"
 332     "    Prints all arguments with the default values for a build with the\n"
 333     "    given arguments set (which may affect the values of other\n"
 334     "    arguments).\n";
 335
 336 int RunArgs(const std::vector<std::string>& args) {
 337   if (args.size() != 1) {
 338     Err(Location(), "Exactly one build dir needed.",
 339         "Usage: \"gn args <out_dir>\"\n"
 340         "Or see \"gn help args\" for more variants.").PrintToStdout();
 341     return 1;
 342   }
 343
 344   if (base::CommandLine::ForCurrentProcess()->HasSwitch(kSwitchList))
 345     return ListArgs(args[0]);
 346   return EditArgsFile(args[0]);
 347 }
 348
 349 }  // namespace commands