Add soong_build primary builder

Initial build logic for building android with soong.  It can build
a variety of C and C++ files for arm/arm64 and host.

Change-Id: I10eb37c2c2a50be6af1bb5fd568c0962b9476bf0

common/glob.go

@@ -0,0 +1,133 @@
+// Copyright 2015 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 common
+
+import (
+	"fmt"
+	"path/filepath"
+
+	"blueprint"
+	"blueprint/bootstrap"
+
+	"android/soong/glob"
+)
+
+// This file supports globbing source files in Blueprints files.
+//
+// The build.ninja file needs to be regenerated any time a file matching the glob is added
+// or removed.  The naive solution is to have the build.ninja file depend on all the
+// traversed directories, but this will cause the regeneration step to run every time a
+// non-matching file is added to a traversed directory, including backup files created by
+// editors.
+//
+// The solution implemented here optimizes out regenerations when the directory modifications
+// don't match the glob by having the build.ninja file depend on an intermedate file that
+// is only updated when a file matching the glob is added or removed.  The intermediate file
+// depends on the traversed directories via a depfile.  The depfile is used to avoid build
+// errors if a directory is deleted - a direct dependency on the deleted directory would result
+// in a build failure with a "missing and no known rule to make it" error.
+
+var (
+	globCmd = filepath.Join(bootstrap.BinDir, "soong_glob")
+
+	// globRule rule traverses directories to produce a list of files that match $glob
+	// and writes it to $out if it has changed, and writes the directories to $out.d
+	globRule = pctx.StaticRule("globRule",
+		blueprint.RuleParams{
+			Command:     fmt.Sprintf(`%s -o $out "$glob"`, globCmd),
+			Description: "glob $glob",
+
+			Restat:    true,
+			Generator: true,
+			Deps:      blueprint.DepsGCC,
+			Depfile:   "$out.d",
+		},
+		"glob")
+)
+
+func hasGlob(in []string) bool {
+	for _, s := range in {
+		if glob.IsGlob(s) {
+			return true
+		}
+	}
+
+	return false
+}
+
+func ExpandGlobs(ctx AndroidModuleContext, in []string) []string {
+	if !hasGlob(in) {
+		return in
+	}
+
+	out := make([]string, 0, len(in))
+	for _, s := range in {
+		if glob.IsGlob(s) {
+			out = append(out, Glob(ctx, s)...)
+		} else {
+			out = append(out, s)
+		}
+	}
+
+	return out
+}
+
+func Glob(ctx AndroidModuleContext, globPattern string) []string {
+	fileListFile := filepath.Join(ModuleOutDir(ctx), "glob", globToString(globPattern))
+	depFile := fileListFile + ".d"
+
+	// Get a globbed file list, and write out fileListFile and depFile
+	files, err := glob.GlobWithDepFile(globPattern, fileListFile, depFile)
+	if err != nil {
+		ctx.ModuleErrorf("glob: %s", err.Error())
+		return []string{globPattern}
+	}
+
+	// Create a rule to rebuild fileListFile if a directory in depFile changes.  fileListFile
+	// will only be rewritten if it has changed, preventing unnecesary build.ninja regenerations.
+	ctx.Build(pctx, blueprint.BuildParams{
+		Rule:      globRule,
+		Outputs:   []string{fileListFile},
+		Implicits: []string{globCmd},
+		Args: map[string]string{
+			"glob": globPattern,
+		},
+	})
+
+	// Phony rule so the cleanup phase doesn't delete the depFile
+	ctx.Build(pctx, blueprint.BuildParams{
+		Rule:    blueprint.Phony,
+		Outputs: []string{depFile},
+	})
+
+	// Make build.ninja depend on the fileListFile
+	ctx.AddNinjaFileDeps(fileListFile)
+
+	return files
+}
+
+func globToString(glob string) string {
+	ret := ""
+	for _, c := range glob {
+		if c >= 'a' && c <= 'z' ||
+			c >= 'A' && c <= 'Z' ||
+			c >= '0' && c <= '9' ||
+			c == '_' || c == '-' || c == '/' {
+			ret += string(c)
+		}
+	}
+
+	return ret
+}