tools/gn/file_template.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 "tools/gn/file_template.h"
   6
   7 #include <algorithm>
   8 #include <iostream>
   9
  10 #include "tools/gn/escape.h"
  11 #include "tools/gn/filesystem_utils.h"
  12 #include "tools/gn/string_utils.h"
  13 #include "tools/gn/target.h"
  14
  15 const char FileTemplate::kSource[] = "{{source}}";
  16 const char FileTemplate::kSourceNamePart[] = "{{source_name_part}}";
  17 const char FileTemplate::kSourceFilePart[] = "{{source_file_part}}";
  18
  19 const char kSourceExpansion_Help[] =
  20     "How Source Expansion Works\n"
  21     "\n"
  22     "  Source expansion is used for the action_foreach and copy target types\n"
  23     "  to map source file names to output file names or arguments.\n"
  24     "\n"
  25     "  To perform source expansion in the outputs, GN maps every entry in the\n"
  26     "  sources to every entry in the outputs list, producing the cross\n"
  27     "  product of all combinations, expanding placeholders (see below).\n"
  28     "\n"
  29     "  Source expansion in the args works similarly, but performing the\n"
  30     "  placeholder substitution produces a different set of arguments for\n"
  31     "  each invocation of the script.\n"
  32     "\n"
  33     "  If no placeholders are found, the outputs or args list will be treated\n"
  34     "  as a static list of literal file names that do not depend on the\n"
  35     "  sources.\n"
  36     "\n"
  37     "  See \"gn help copy\" and \"gn help action_foreach\" for more on how\n"
  38     "  this is applied.\n"
  39     "\n"
  40     "Placeholders\n"
  41     "\n"
  42     "  {{source}}\n"
  43     "      The name of the source file relative to the root build output\n"
  44     "      directory (which is the current directory when running compilers\n"
  45     "      and scripts). This will generally be used for specifying inputs\n"
  46     "      to a script in the \"args\" variable.\n"
  47     "\n"
  48     "  {{source_file_part}}\n"
  49     "      The file part of the source including the extension. For the\n"
  50     "      source \"foo/bar.txt\" the source file part will be \"bar.txt\".\n"
  51     "\n"
  52     "  {{source_name_part}}\n"
  53     "      The filename part of the source file with no directory or\n"
  54     "      extension. This will generally be used for specifying a\n"
  55     "      transformation from a soruce file to a destination file with the\n"
  56     "      same name but different extension. For the source \"foo/bar.txt\"\n"
  57     "      the source name part will be \"bar\".\n"
  58     "\n"
  59     "Examples\n"
  60     "\n"
  61     "  Non-varying outputs:\n"
  62     "    action(\"hardcoded_outputs\") {\n"
  63     "      sources = [ \"input1.idl\", \"input2.idl\" ]\n"
  64     "      outputs = [ \"$target_out_dir/output1.dat\",\n"
  65     "                  \"$target_out_dir/output2.dat\" ]\n"
  66     "    }\n"
  67     "  The outputs in this case will be the two literal files given.\n"
  68     "\n"
  69     "  Varying outputs:\n"
  70     "    action_foreach(\"varying_outputs\") {\n"
  71     "      sources = [ \"input1.idl\", \"input2.idl\" ]\n"
  72     "      outputs = [ \"$target_out_dir/{{source_name_part}}.h\",\n"
  73     "                  \"$target_out_dir/{{source_name_part}}.cc\" ]\n"
  74     "    }\n"
  75     "  Performing source expansion will result in the following output names:\n"
  76     "    //out/Debug/obj/mydirectory/input1.h\n"
  77     "    //out/Debug/obj/mydirectory/input1.cc\n"
  78     "    //out/Debug/obj/mydirectory/input2.h\n"
  79     "    //out/Debug/obj/mydirectory/input2.cc\n";
  80
  81 FileTemplate::FileTemplate(const Value& t, Err* err)
  82     : has_substitutions_(false) {
  83   std::fill(types_required_, &types_required_[Subrange::NUM_TYPES], false);
  84   ParseInput(t, err);
  85 }
  86
  87 FileTemplate::FileTemplate(const std::vector<std::string>& t)
  88     : has_substitutions_(false) {
  89   std::fill(types_required_, &types_required_[Subrange::NUM_TYPES], false);
  90   for (size_t i = 0; i < t.size(); i++)
  91     ParseOneTemplateString(t[i]);
  92 }
  93
  94 FileTemplate::~FileTemplate() {
  95 }
  96
  97 // static
  98 FileTemplate FileTemplate::GetForTargetOutputs(const Target* target) {
  99   const Target::FileList& outputs = target->action_values().outputs();
 100   std::vector<std::string> output_template_args;
 101   for (size_t i = 0; i < outputs.size(); i++)
 102     output_template_args.push_back(outputs[i].value());
 103   return FileTemplate(output_template_args);
 104 }
 105
 106 bool FileTemplate::IsTypeUsed(Subrange::Type type) const {
 107   DCHECK(type > Subrange::LITERAL && type < Subrange::NUM_TYPES);
 108   return types_required_[type];
 109 }
 110
 111 void FileTemplate::Apply(const Value& sources,
 112                          const ParseNode* origin,
 113                          std::vector<Value>* dest,
 114                          Err* err) const {
 115   if (!sources.VerifyTypeIs(Value::LIST, err))
 116     return;
 117   dest->reserve(sources.list_value().size() * templates_.container().size());
 118
 119   // Temporary holding place, allocate outside to re-use- buffer.
 120   std::vector<std::string> string_output;
 121
 122   const std::vector<Value>& sources_list = sources.list_value();
 123   for (size_t i = 0; i < sources_list.size(); i++) {
 124     if (!sources_list[i].VerifyTypeIs(Value::STRING, err))
 125       return;
 126
 127     ApplyString(sources_list[i].string_value(), &string_output);
 128     for (size_t out_i = 0; out_i < string_output.size(); out_i++)
 129       dest->push_back(Value(origin, string_output[out_i]));
 130   }
 131 }
 132
 133 void FileTemplate::ApplyString(const std::string& str,
 134                                std::vector<std::string>* output) const {
 135   // Compute all substitutions needed so we can just do substitutions below.
 136   // We skip the LITERAL one since that varies each time.
 137   std::string subst[Subrange::NUM_TYPES];
 138   for (int i = 1; i < Subrange::NUM_TYPES; i++) {
 139     if (types_required_[i])
 140       subst[i] = GetSubstitution(str, static_cast<Subrange::Type>(i));
 141   }
 142
 143   output->resize(templates_.container().size());
 144   for (size_t template_i = 0;
 145        template_i < templates_.container().size(); template_i++) {
 146     const Template& t = templates_[template_i];
 147     (*output)[template_i].clear();
 148     for (size_t subrange_i = 0; subrange_i < t.container().size();
 149          subrange_i++) {
 150       if (t[subrange_i].type == Subrange::LITERAL)
 151         (*output)[template_i].append(t[subrange_i].literal);
 152       else
 153         (*output)[template_i].append(subst[t[subrange_i].type]);
 154     }
 155   }
 156 }
 157
 158 void FileTemplate::WriteWithNinjaExpansions(std::ostream& out) const {
 159   EscapeOptions escape_options;
 160   escape_options.mode = ESCAPE_NINJA_SHELL;
 161   escape_options.inhibit_quoting = true;
 162
 163   for (size_t template_i = 0;
 164        template_i < templates_.container().size(); template_i++) {
 165     out << " ";  // Separate args with spaces.
 166
 167     const Template& t = templates_[template_i];
 168
 169     // Escape each subrange into a string. Since we're writing out Ninja
 170     // variables, we can't quote the whole thing, so we write in pieces, only
 171     // escaping the literals, and then quoting the whole thing at the end if
 172     // necessary.
 173     bool needs_quoting = false;
 174     std::string item_str;
 175     for (size_t subrange_i = 0; subrange_i < t.container().size();
 176          subrange_i++) {
 177       if (t[subrange_i].type == Subrange::LITERAL) {
 178         item_str.append(EscapeString(t[subrange_i].literal, escape_options,
 179                                      &needs_quoting));
 180       } else {
 181         // Don't escape this since we need to preserve the $.
 182         item_str.append("${");
 183         item_str.append(GetNinjaVariableNameForType(t[subrange_i].type));
 184         item_str.append("}");
 185       }
 186     }
 187
 188     if (needs_quoting) {
 189       // Need to shell quote the whole string.
 190       out << '"' << item_str << '"';
 191     } else {
 192       out << item_str;
 193     }
 194   }
 195 }
 196
 197 void FileTemplate::WriteNinjaVariablesForSubstitution(
 198     std::ostream& out,
 199     const std::string& source,
 200     const EscapeOptions& escape_options) const {
 201   for (int i = 1; i < Subrange::NUM_TYPES; i++) {
 202     if (types_required_[i]) {
 203       Subrange::Type type = static_cast<Subrange::Type>(i);
 204       out << "  " << GetNinjaVariableNameForType(type) << " = ";
 205       EscapeStringToStream(out, GetSubstitution(source, type), escape_options);
 206       out << std::endl;
 207     }
 208   }
 209 }
 210
 211 // static
 212 const char* FileTemplate::GetNinjaVariableNameForType(Subrange::Type type) {
 213   switch (type) {
 214     case Subrange::SOURCE:
 215       return "source";
 216     case Subrange::NAME_PART:
 217       return "source_name_part";
 218     case Subrange::FILE_PART:
 219       return "source_file_part";
 220     default:
 221       NOTREACHED();
 222   }
 223   return "";
 224 }
 225
 226 // static
 227 std::string FileTemplate::GetSubstitution(const std::string& source,
 228                                           Subrange::Type type) {
 229   switch (type) {
 230     case Subrange::SOURCE:
 231       return source;
 232     case Subrange::NAME_PART:
 233       return FindFilenameNoExtension(&source).as_string();
 234     case Subrange::FILE_PART:
 235       return FindFilename(&source).as_string();
 236     default:
 237       NOTREACHED();
 238   }
 239   return std::string();
 240 }
 241
 242 void FileTemplate::ParseInput(const Value& value, Err* err) {
 243   switch (value.type()) {
 244     case Value::STRING:
 245       ParseOneTemplateString(value.string_value());
 246       break;
 247     case Value::LIST:
 248       for (size_t i = 0; i < value.list_value().size(); i++) {
 249         if (!value.list_value()[i].VerifyTypeIs(Value::STRING, err))
 250           return;
 251         ParseOneTemplateString(value.list_value()[i].string_value());
 252       }
 253       break;
 254     default:
 255       *err = Err(value, "File template must be a string or list.",
 256                  "A sarcastic comment about your skills goes here.");
 257   }
 258 }
 259
 260 void FileTemplate::ParseOneTemplateString(const std::string& str) {
 261   templates_.container().resize(templates_.container().size() + 1);
 262   Template& t = templates_[templates_.container().size() - 1];
 263
 264   size_t cur = 0;
 265   while (true) {
 266     size_t next = str.find("{{", cur);
 267
 268     // Pick up everything from the previous spot to here as a literal.
 269     if (next == std::string::npos) {
 270       if (cur != str.size())
 271         t.container().push_back(Subrange(Subrange::LITERAL, str.substr(cur)));
 272       break;
 273     } else if (next > cur) {
 274       t.container().push_back(
 275           Subrange(Subrange::LITERAL, str.substr(cur, next - cur)));
 276     }
 277
 278     // Decode the template param.
 279     if (str.compare(next, arraysize(kSource) - 1, kSource) == 0) {
 280       t.container().push_back(Subrange(Subrange::SOURCE));
 281       types_required_[Subrange::SOURCE] = true;
 282       has_substitutions_ = true;
 283       cur = next + arraysize(kSource) - 1;
 284     } else if (str.compare(next, arraysize(kSourceNamePart) - 1,
 285                            kSourceNamePart) == 0) {
 286       t.container().push_back(Subrange(Subrange::NAME_PART));
 287       types_required_[Subrange::NAME_PART] = true;
 288       has_substitutions_ = true;
 289       cur = next + arraysize(kSourceNamePart) - 1;
 290     } else if (str.compare(next, arraysize(kSourceFilePart) - 1,
 291                            kSourceFilePart) == 0) {
 292       t.container().push_back(Subrange(Subrange::FILE_PART));
 293       types_required_[Subrange::FILE_PART] = true;
 294       has_substitutions_ = true;
 295       cur = next + arraysize(kSourceFilePart) - 1;
 296     } else {
 297       // If it's not a match, treat it like a one-char literal (this will be
 298       // rare, so it's not worth the bother to add to the previous literal) so
 299       // we can keep going.
 300       t.container().push_back(Subrange(Subrange::LITERAL, "{"));
 301       cur = next + 1;
 302     }
 303   }
 304 }