Support for source_target_relative expansion in GN

tools/gn/substitution_type.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/substitution_type.h"
 
 #include <stddef.h>
 #include <stdlib.h>
 
 #include "tools/gn/err.h"
 
 const char* kSubstitutionNames[SUBSTITUTION_NUM_TYPES] = {
   "<<literal>>",  // SUBSTITUTION_LITERAL
 
   "{{source}}",  // SUBSTITUTION_SOURCE
   "{{output}}",  // SUBSTITUTION_OUTPUT
 
   "{{source_name_part}}",  // SUBSTITUTION_NAME_PART
   "{{source_file_part}}",  // SUBSTITUTION_FILE_PART
   "{{source_dir}}",  // SUBSTITUTION_SOURCE_DIR
   "{{source_root_relative_dir}}",  // SUBSTITUTION_SOURCE_ROOT_RELATIVE_DIR
   "{{source_gen_dir}}",  // SUBSTITUTION_SOURCE_GEN_DIR
   "{{source_out_dir}}",  // SUBSTITUTION_SOURCE_OUT_DIR
+  "{{source_target_relative}}",  // SUBSTITUTION_SOURCE_TARGET_RELATIVE
 
   "{{label}}",  // SUBSTITUTION_LABEL
   "{{label_name}}",  // SUBSTITUTION_LABEL_NAME
   "{{root_gen_dir}}",  // SUBSTITUTION_ROOT_GEN_DIR
   "{{root_out_dir}}",  // SUBSTITUTION_ROOT_OUT_DIR
   "{{target_gen_dir}}",  // SUBSTITUTION_TARGET_GEN_DIR
   "{{target_out_dir}}",  // SUBSTITUTION_TARGET_OUT_DIR
   "{{target_output_name}}",  // SUBSTITUTION_TARGET_OUTPUT_NAME
 
   "{{asmflags}}",  // SUBSTITUTION_ASMFLAGS
@@ skipping 29 matching lines @@
 
     "in",   // SUBSTITUTION_SOURCE
     "out",  // SUBSTITUTION_OUTPUT
 
     "source_name_part",          // SUBSTITUTION_NAME_PART
     "source_file_part",          // SUBSTITUTION_FILE_PART
     "source_dir",                // SUBSTITUTION_SOURCE_DIR
     "source_root_relative_dir",  // SUBSTITUTION_SOURCE_ROOT_RELATIVE_DIR
     "source_gen_dir",            // SUBSTITUTION_SOURCE_GEN_DIR
     "source_out_dir",            // SUBSTITUTION_SOURCE_OUT_DIR
+    "source_target_relative",    // SUBSTITUTION_SOURCE_TARGET_RELATIVE
 
     "label",               // SUBSTITUTION_LABEL
     "label_name",          // SUBSTITUTION_LABEL_NAME
     "root_gen_dir",        // SUBSTITUTION_ROOT_GEN_DIR
     "root_out_dir",        // SUBSTITUTION_ROOT_OUT_DIR
     "target_gen_dir",      // SUBSTITUTION_TARGET_GEN_DIR
     "target_out_dir",      // SUBSTITUTION_TARGET_OUT_DIR
     "target_output_name",  // SUBSTITUTION_TARGET_OUTPUT_NAME
 
     "asmflags",      // SUBSTITUTION_ASMFLAGS
@@ skipping 70 matching lines @@
 }
 
 bool IsValidSourceSubstitution(SubstitutionType type) {
   return type == SUBSTITUTION_LITERAL ||
          type == SUBSTITUTION_SOURCE ||
          type == SUBSTITUTION_SOURCE_NAME_PART ||
          type == SUBSTITUTION_SOURCE_FILE_PART ||
          type == SUBSTITUTION_SOURCE_DIR ||
          type == SUBSTITUTION_SOURCE_ROOT_RELATIVE_DIR ||
          type == SUBSTITUTION_SOURCE_GEN_DIR ||
-         type == SUBSTITUTION_SOURCE_OUT_DIR;
+         type == SUBSTITUTION_SOURCE_OUT_DIR ||
+         type == SUBSTITUTION_SOURCE_TARGET_RELATIVE;
 }
 
 bool IsValidToolSubstitution(SubstitutionType type) {
   return type == SUBSTITUTION_LITERAL ||
          type == SUBSTITUTION_OUTPUT ||
          type == SUBSTITUTION_LABEL ||
          type == SUBSTITUTION_LABEL_NAME ||
          type == SUBSTITUTION_ROOT_GEN_DIR ||
          type == SUBSTITUTION_ROOT_OUT_DIR ||
          type == SUBSTITUTION_TARGET_GEN_DIR ||
@@ skipping 67 matching lines @@
     if (!IsValidSourceSubstitution(types[i])) {
       *err = Err(origin, "Invalid substitution type.",
           "The substitution " + std::string(kSubstitutionNames[types[i]]) +
           " isn't valid for something\n"
           "operating on a source file such as this.");
       return false;
     }
   }
   return true;
 }