Add support for outputting dependency manifest files, used by ninja and make

Use --manifest-file=somefile.d to output the dependency manifest.
This file will contain a list of files which were read by protoc as part
of creating the output files.  It doesn't include the plugin inputs if
plugins are used, that could be a later extension.
The manifest file is in the format <output file>: <input files>.  The
manifest file format only allows you to specify one output file, which
isn't a problem as it's used to detect input changes in order to detect
when to rerun the protoc command.  The output file used in the manifest
is the manifest filename itself; to use this in ninja you should declare
the manifest file as the first output as well as the depfile input.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/google/protobuf/compiler/command_line_interface.h b/src/google/protobuf/compiler/command_line_interface.h
index 74a0adb4..59d57fbf 100644
--- a/src/google/protobuf/compiler/command_line_interface.h
+++ b/src/google/protobuf/compiler/command_line_interface.h
@@ -247,6 +247,11 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // Implements the --descriptor_set_out option.
   bool WriteDescriptorSet(const vector<const FileDescriptor*> parsed_files);
 
+  // Implements the --manifest-file option
+  bool GenerateDependencyManifestFile(
+      const vector<const FileDescriptor*> parsed_files,
+      DiskSourceTree * source_tree);
+
   // Get all transitive dependencies of the given file (including the file
   // itself), adding them to the given list of FileDescriptorProtos.  The
   // protos will be ordered such that every file is listed before any file that
@@ -353,6 +358,10 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // FileDescriptorSet should be written.  Otherwise, empty.
   string descriptor_set_name_;
 
+  // If --manifest_file was given, this is the filename to which the input
+  // file should be written.  Otherwise, empty.
+  string manifest_name_;
+
   // True if --include_imports was given, meaning that we should
   // write all transitive dependencies to the DescriptorSet.  Otherwise, only
   // the .proto files listed on the command-line are added.