Refactor proto in preparation for java proto support

Test: m -j checkbuild
Change-Id: Idf00ea0bacb2777458f9af2c7eb47e1e1854eeba

1 files changed, 103 insertions, 0 deletions

diff --git a/android/proto.go b/android/proto.go
new file mode 100644
index 00000000..9bb9cfbb
--- /dev/null
+++ b/android/proto.go
@@ -0,0 +1,103 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"github.com/google/blueprint"
+)
+
+func init() {
+	pctx.HostBinToolVariable("protocCmd", "aprotoc")
+}
+
+var (
+	proto = pctx.AndroidStaticRule("protoc",
+		blueprint.RuleParams{
+			Command:     "$protocCmd $protoOut=$protoOutFlags:$outDir $protoFlags $in",
+			CommandDeps: []string{"$protocCmd"},
+		}, "protoFlags", "protoOut", "protoOutFlags", "outDir")
+)
+
+// TODO(ccross): protos are often used to communicate between multiple modules.  If the only
+// way to convert a proto to source is to reference it as a source file, and external modules cannot
+// reference source files in other modules, then every module that owns a proto file will need to
+// export a library for every type of external user (lite vs. full, c vs. c++ vs. java).  It would
+// be better to support a proto module type that exported a proto file along with some include dirs,
+// and then external modules could depend on the proto module but use their own settings to
+// generate the source.
+
+func GenProto(ctx ModuleContext, protoFile Path,
+	protoFlags string, protoOut, protoOutFlags string, extensions []string) WritablePaths {
+
+	var outFiles WritablePaths
+	for _, ext := range extensions {
+		outFiles = append(outFiles, GenPathWithExt(ctx, "proto", protoFile, ext))
+	}
+
+	ctx.ModuleBuild(pctx, ModuleBuildParams{
+		Rule:        proto,
+		Description: "protoc " + protoFile.Rel(),
+		Outputs:     outFiles,
+		Input:       protoFile,
+		Args: map[string]string{
+			"outDir":        ProtoDir(ctx).String(),
+			"protoOut":      protoOut,
+			"protoOutFlags": protoOutFlags,
+			"protoFlags":    protoFlags,
+		},
+	})
+
+	return outFiles
+}
+
+func ProtoFlags(ctx ModuleContext, p *ProtoProperties) []string {
+	var protoFlags []string
+	if len(p.Proto.Local_include_dirs) > 0 {
+		localProtoIncludeDirs := PathsForModuleSrc(ctx, p.Proto.Local_include_dirs)
+		protoFlags = append(protoFlags, JoinWithPrefix(localProtoIncludeDirs.Strings(), "-I"))
+	}
+	if len(p.Proto.Include_dirs) > 0 {
+		rootProtoIncludeDirs := PathsForSource(ctx, p.Proto.Include_dirs)
+		protoFlags = append(protoFlags, JoinWithPrefix(rootProtoIncludeDirs.Strings(), "-I"))
+	}
+
+	protoFlags = append(protoFlags, "-I .")
+
+	return protoFlags
+}
+
+// ProtoDir returns the module's "gen/proto" directory
+func ProtoDir(ctx ModuleContext) ModuleGenPath {
+	return PathForModuleGen(ctx, "proto")
+}
+
+// ProtoSubDir returns the module's "gen/proto/path/to/module" directory
+func ProtoSubDir(ctx ModuleContext) ModuleGenPath {
+	return PathForModuleGen(ctx, "proto", ctx.ModuleDir())
+}
+
+type ProtoProperties struct {
+	Proto struct {
+		// Proto generator type.  C++: full or lite.  Java: micro, nano, stream, or lite.
+		Type *string `android:"arch_variant"`
+
+		// list of directories that will be added to the protoc include paths.
+		Include_dirs []string
+
+		// list of directories relative to the bp file that will
+		// be added to the protoc include paths.
+		Local_include_dirs []string
+	} `android:"arch_variant"`
+}