tools/gn/function_get_target_outputs.cc

   1 // Copyright 2014 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/build_settings.h"
   6 #include "tools/gn/functions.h"
   7 #include "tools/gn/parse_tree.h"
   8 #include "tools/gn/settings.h"
   9 #include "tools/gn/substitution_writer.h"
  10 #include "tools/gn/target.h"
  11 #include "tools/gn/value.h"
  12
  13 namespace functions {
  14
  15 const char kGetTargetOutputs[] = "get_target_outputs";
  16 const char kGetTargetOutputs_HelpShort[] =
  17     "get_target_outputs: [file list] Get the list of outputs from a target.";
  18 const char kGetTargetOutputs_Help[] =
  19     "get_target_outputs: [file list] Get the list of outputs from a target.\n"
  20     "\n"
  21     "  get_target_outputs(target_label)\n"
  22     "\n"
  23     "  Returns a list of output files for the named target. The named target\n"
  24     "  must have been previously defined in the current file before this\n"
  25     "  function is called (it can't reference targets in other files because\n"
  26     "  there isn't a defined execution order, and it obviously can't\n"
  27     "  reference targets that are defined after the function call).\n"
  28     "\n"
  29     "  Only copy and action targets are supported. The outputs from binary\n"
  30     "  targets will depend on the toolchain definition which won't\n"
  31     "  necessarily have been loaded by the time a given line of code has run,\n"
  32     "  and source sets and groups have no useful output file.\n"
  33     "\n"
  34     "Return value\n"
  35     "\n"
  36     "  The names in the resulting list will be absolute file paths (normally\n"
  37     "  like \"//out/Debug/bar.exe\", depending on the build directory).\n"
  38     "\n"
  39     "  action targets: this will just return the files specified in the\n"
  40     "  \"outputs\" variable of the target.\n"
  41     "\n"
  42     "  action_foreach targets: this will return the result of applying\n"
  43     "  the output template to the sources (see \"gn help source_expansion\").\n"
  44     "  This will be the same result (though with guaranteed absolute file\n"
  45     "  paths), as process_file_template will return for those inputs\n"
  46     "  (see \"gn help process_file_template\").\n"
  47     "\n"
  48     "  binary targets (executables, libraries): this will return a list\n"
  49     "  of the resulting binary file(s). The \"main output\" (the actual\n"
  50     "  binary or library) will always be the 0th element in the result.\n"
  51     "  Depending on the platform and output type, there may be other output\n"
  52     "  files as well (like import libraries) which will follow.\n"
  53     "\n"
  54     "  source sets and groups: this will return a list containing the path of\n"
  55     "  the \"stamp\" file that Ninja will produce once all outputs are\n"
  56     "  generated. This probably isn't very useful.\n"
  57     "\n"
  58     "Example\n"
  59     "\n"
  60     "  # Say this action generates a bunch of C source files.\n"
  61     "  action_foreach(\"my_action\") {\n"
  62     "    sources = [ ... ]\n"
  63     "    outputs = [ ... ]\n"
  64     "  }\n"
  65     "\n"
  66     "  # Compile the resulting source files into a source set.\n"
  67     "  source_set(\"my_lib\") {\n"
  68     "    sources = get_target_outputs(\":my_action\")\n"
  69     "  }\n";
  70
  71 Value RunGetTargetOutputs(Scope* scope,
  72                           const FunctionCallNode* function,
  73                           const std::vector<Value>& args,
  74                           Err* err) {
  75   if (args.size() != 1) {
  76     *err = Err(function, "Expected one argument.");
  77     return Value();
  78   }
  79
  80   // Resolve the requested label.
  81   Label label = Label::Resolve(scope->GetSourceDir(),
  82                                ToolchainLabelForScope(scope), args[0], err);
  83   if (label.is_null())
  84     return Value();
  85
  86   // Find the referenced target. The targets previously encountered in this
  87   // scope will have been stashed in the item collector (they'll be dispatched
  88   // when this file is done running) so we can look through them.
  89   const Target* target = nullptr;
  90   Scope::ItemVector* collector = scope->GetItemCollector();
  91   if (!collector) {
  92     *err = Err(function, "No targets defined in this context.");
  93     return Value();
  94   }
  95   for (const auto& item : *collector) {
  96     if (item->label() != label)
  97       continue;
  98
  99     const Target* as_target = item->AsTarget();
 100     if (!as_target) {
 101       *err = Err(function, "Label does not refer to a target.",
 102           label.GetUserVisibleName(false) +
 103           "\nrefers to a " + item->GetItemTypeName());
 104       return Value();
 105     }
 106     target = as_target;
 107     break;
 108   }
 109
 110   if (!target) {
 111     *err = Err(function, "Target not found in this context.",
 112         label.GetUserVisibleName(false) +
 113         "\nwas not found. get_target_outputs() can only be used for targets\n"
 114         "previously defined in the current file.");
 115     return Value();
 116   }
 117
 118   // Compute the output list.
 119   std::vector<SourceFile> files;
 120   if (target->output_type() == Target::ACTION ||
 121       target->output_type() == Target::COPY_FILES ||
 122       target->output_type() == Target::ACTION_FOREACH) {
 123     target->action_values().GetOutputsAsSourceFiles(target, &files);
 124   } else {
 125     // Other types of targets are not supported.
 126     *err = Err(args[0], "Target is not an action, action_foreach, or copy.",
 127                "Only these target types are supported by get_target_outputs.");
 128     return Value();
 129   }
 130
 131   // Convert to Values.
 132   Value ret(function, Value::LIST);
 133   ret.list_value().reserve(files.size());
 134   for (const auto& file : files)
 135     ret.list_value().push_back(Value(function, file.value()));
 136
 137   return ret;
 138 }
 139
 140 }  // namespace functions