tools/gn/command_help.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 <algorithm>
   6 #include <iostream>
   7
   8 #include "tools/gn/args.h"
   9 #include "tools/gn/commands.h"
  10 #include "tools/gn/err.h"
  11 #include "tools/gn/functions.h"
  12 #include "tools/gn/input_conversion.h"
  13 #include "tools/gn/label_pattern.h"
  14 #include "tools/gn/setup.h"
  15 #include "tools/gn/standard_out.h"
  16 #include "tools/gn/substitution_writer.h"
  17 #include "tools/gn/variables.h"
  18
  19 namespace commands {
  20
  21 namespace {
  22
  23 void PrintToplevelHelp() {
  24   OutputString("Commands (type \"gn help <command>\" for more details):\n");
  25   for (const auto& cmd : commands::GetCommands())
  26     PrintShortHelp(cmd.second.help_short);
  27
  28   OutputString(
  29       "\n"
  30       "Common switches:\n");
  31   PrintShortHelp(
  32       "--args: Specifies build arguments overrides. "
  33       "See \"gn help buildargs\".");
  34   PrintShortHelp(
  35       "--[no]color: Forces colored output on or off (rather than autodetect).");
  36   PrintShortHelp(
  37       "--dotfile: Specifies an alternate .gn file. See \"gn help dotfile\".");
  38   PrintShortHelp(
  39       "--no-exec: Skips exec_script calls (for performance testing).");
  40   PrintShortHelp(
  41       "-q: Quiet mode, don't print anything on success.");
  42   PrintShortHelp(
  43       "--root: Specifies source root (overrides .gn file).");
  44   PrintShortHelp(
  45       "--time: Outputs a summary of how long everything took.");
  46   PrintShortHelp(
  47       "--tracelog: Writes a Chrome-compatible trace log to the given file.");
  48   PrintShortHelp(
  49       "-v: Verbose mode, print lots of logging.");
  50   PrintShortHelp(
  51       "--version: Print the GN binary's version and exit.");
  52
  53   // Target declarations.
  54   OutputString("\nTarget declarations (type \"gn help <function>\" for more "
  55                "details):\n");
  56   for (const auto& func : functions::GetFunctions()) {
  57     if (func.second.is_target)
  58       PrintShortHelp(func.second.help_short);
  59   }
  60
  61   // Functions.
  62   OutputString("\nBuildfile functions (type \"gn help <function>\" for more "
  63                "details):\n");
  64   for (const auto& func : functions::GetFunctions()) {
  65     if (!func.second.is_target)
  66       PrintShortHelp(func.second.help_short);
  67   }
  68
  69   // Built-in variables.
  70   OutputString("\nBuilt-in predefined variables (type \"gn help <variable>\" "
  71                "for more details):\n");
  72   for (const auto& builtin : variables::GetBuiltinVariables())
  73     PrintShortHelp(builtin.second.help_short);
  74
  75   // Target variables.
  76   OutputString("\nVariables you set in targets (type \"gn help <variable>\" "
  77                "for more details):\n");
  78   for (const auto& target : variables::GetTargetVariables())
  79     PrintShortHelp(target.second.help_short);
  80
  81   OutputString("\nOther help topics:\n");
  82   PrintShortHelp("buildargs: How build arguments work.");
  83   PrintShortHelp("dotfile: Info about the toplevel .gn file.");
  84   PrintShortHelp("label_pattern: Matching more than one label.");
  85   PrintShortHelp(
  86       "input_conversion: Processing input from exec_script and read_file.");
  87   PrintShortHelp("source_expansion: Map sources to outputs for scripts.");
  88 }
  89
  90 }  // namespace
  91
  92 const char kHelp[] = "help";
  93 const char kHelp_HelpShort[] =
  94     "help: Does what you think.";
  95 const char kHelp_Help[] =
  96     "gn help <anything>\n"
  97     "  Yo dawg, I heard you like help on your help so I put help on the help\n"
  98     "  in the help.\n";
  99
 100 int RunHelp(const std::vector<std::string>& args) {
 101   if (args.size() == 0) {
 102     PrintToplevelHelp();
 103     return 0;
 104   }
 105
 106   // Check commands.
 107   const commands::CommandInfoMap& command_map = commands::GetCommands();
 108   commands::CommandInfoMap::const_iterator found_command =
 109       command_map.find(args[0]);
 110   if (found_command != command_map.end()) {
 111     PrintLongHelp(found_command->second.help);
 112     return 0;
 113   }
 114
 115   // Check functions.
 116   const functions::FunctionInfoMap& function_map = functions::GetFunctions();
 117   functions::FunctionInfoMap::const_iterator found_function =
 118       function_map.find(args[0]);
 119   if (found_function != function_map.end()) {
 120     PrintLongHelp(found_function->second.help);
 121     return 0;
 122   }
 123
 124   // Builtin variables.
 125   const variables::VariableInfoMap& builtin_vars =
 126       variables::GetBuiltinVariables();
 127   variables::VariableInfoMap::const_iterator found_builtin_var =
 128       builtin_vars.find(args[0]);
 129   if (found_builtin_var != builtin_vars.end()) {
 130     PrintLongHelp(found_builtin_var->second.help);
 131     return 0;
 132   }
 133
 134   // Target variables.
 135   const variables::VariableInfoMap& target_vars =
 136       variables::GetTargetVariables();
 137   variables::VariableInfoMap::const_iterator found_target_var =
 138       target_vars.find(args[0]);
 139   if (found_target_var != target_vars.end()) {
 140     PrintLongHelp(found_target_var->second.help);
 141     return 0;
 142   }
 143
 144   // Random other topics.
 145   if (args[0] == "buildargs") {
 146     PrintLongHelp(kBuildArgs_Help);
 147     return 0;
 148   }
 149   if (args[0] == "dotfile") {
 150     PrintLongHelp(kDotfile_Help);
 151     return 0;
 152   }
 153   if (args[0] == "input_conversion") {
 154     PrintLongHelp(kInputConversion_Help);
 155     return 0;
 156   }
 157   if (args[0] == "label_pattern") {
 158     PrintLongHelp(kLabelPattern_Help);
 159     return 0;
 160   }
 161   if (args[0] == "source_expansion") {
 162     PrintLongHelp(kSourceExpansion_Help);
 163     return 0;
 164   }
 165
 166   // No help on this.
 167   Err(Location(), "No help on \"" + args[0] + "\".").PrintToStdout();
 168   RunHelp(std::vector<std::string>());
 169   return 1;
 170 }
 171
 172 }  // namespace commands