Refactor GN source expansions.

tools/gn/substitution_type.h

Index: tools/gn/substitution_type.h
diff --git a/tools/gn/substitution_type.h b/tools/gn/substitution_type.h
new file mode 100644
index 0000000000000000000000000000000000000000..fd7c40692dc70c3cac80657617bd0b62c22c8fb9
--- /dev/null
+++ b/tools/gn/substitution_type.h
@@ -0,0 +1,87 @@
+// 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.
+
+#ifndef TOOLS_GN_SUBSTITUTION_TYPE_H_
+#define TOOLS_GN_SUBSTITUTION_TYPE_H_
+
+#include <vector>
+
+class Err;
+class ParseNode;
+
+// Keep kSubstitutionNames, kSubstitutionNinjaNames and the
+// IsValid*Substutition functions in sync if you change anything here.
+enum SubstitutionType {
+  SUBSTITUTION_LITERAL = 0,
+
+  // The index of the first pattern. To loop overal all patterns, go from here
+  // until NUM_TYPES.
+  SUBSTITUTION_FIRST_PATTERN,
+
+  SUBSTITUTION_SOURCE = SUBSTITUTION_FIRST_PATTERN,  // {{source}}
+  SUBSTITUTION_SOURCE_NAME_PART,  // {{source_name_part}}
+  SUBSTITUTION_SOURCE_FILE_PART,  // {{source_file_part}}
+  SUBSTITUTION_SOURCE_DIR,  // {{source_dir}}
+  SUBSTITUTION_SOURCE_ROOT_RELATIVE_DIR,  // {{root_relative_dir}}
+  SUBSTITUTION_SOURCE_GEN_DIR,  // {{source_gen_dir}}
+  SUBSTITUTION_SOURCE_OUT_DIR,  // {{source_out_dir}}
+
+  // Valid for all compiler and linker tools (depends on target).
+  SUBSTITUTION_OUTPUT,  // {{output}}
+  SUBSTITUTION_ROOT_GEN_DIR,  // {{root_gen_dir}}
+  SUBSTITUTION_ROOT_OUT_DIR,  // {{root_out_dir}}
+  SUBSTITUTION_TARGET_GEN_DIR,  // {{target_gen_dir}}
+  SUBSTITUTION_TARGET_OUT_DIR,  // {{target_out_dir}}
+  SUBSTITUTION_TARGET_OUTPUT_NAME,  // {{target_output_name}}
+
+  // Valid for compiler tools.
+  SUBSTITUTION_CFLAGS,  // {{cflags}}
+  SUBSTITUTION_CFLAGS_C,  // {{cflags_c}}
+  SUBSTITUTION_CFLAGS_CC,  // {{cflags_cc}}
+  SUBSTITUTION_CFLAGS_OBJC,  // {{cflags_objc}}
+  SUBSTITUTION_CFLAGS_OBJCC,  // {{cflags_objcc}}
+  SUBSTITUTION_DEFINES,  // {{defines}}
+  SUBSTITUTION_INCLUDE_DIRS,  // {{include_dirs}}
+
+  // Valid for linker tools.
+  SUBSTITUTION_LINKER_INPUTS,  // {{inputs}}
+  SUBSTITUTION_LDFLAGS,  // {{ldflags}}
+  SUBSTITUTION_LIBS,  // {{libs}}
+  SUBSTITUTION_OUTPUT_EXTENSION,  // {{output_extension}}
+  SUBSTITUTION_SOLIBS,  // {{solibs}}
+
+  SUBSTITUTION_NUM_TYPES  // Must be last.
+};
+
+// An array of size SUBSTITUTION_NUM_TYPES that lists the names of the
+// substitution patterns, including the curly braces. So, for example,
+// kSubstitutionNames[SUBSTITUTION_SOURCE] == "{{source}}".
+extern const char* kSubstitutionNames[SUBSTITUTION_NUM_TYPES];
+
+// Ninja variables corresponding to each substitution. These do not include
+// the dollar sign.
+extern const char* kSubstitutionNinjaNames[SUBSTITUTION_NUM_TYPES];
+
+// Returns true if the given substitution pattern references the output
+// directory. This is used to check strings that begin with a substitution to
+// verify that the produce a file in the output directory.
+bool SubstitutionIsInOutputDir(SubstitutionType type);
+
+// Returns true if the given substitution is valid for the named purpose.
+bool IsValidSourceSubstitution(SubstitutionType type);
+// Both compiler and linker tools.
+bool IsValidToolSubstutition(SubstitutionType type);
+bool IsValidCompilerSubstitution(SubstitutionType type);
+bool IsValidCompilerOutputsSubstitution(SubstitutionType type);
+bool IsValidLinkerSubstitution(SubstitutionType type);
+bool IsValidLinkerOutputsSubstitution(SubstitutionType type);
+
+// Like the "IsValid..." version above but checks a list of types and sets a
+// an error blaming the given source if the test fails.
+bool EnsureValidSourcesSubstitutions(
+    const std::vector<SubstitutionType>& types,
+    const ParseNode* origin,
+    Err* err);
+
+#endif  // TOOLS_GN_SUBSTITUTION_TYPE_H_