Create 'androidmk' rule to automatically run androidbp

This finds any Android.bp files with Android modules defined, and if
there isn't an Android.mk file in the same directory, it will run
androidbp to generate one in $OUT

Change-Id: Ie8aef492e8cd28f6c314ce1254730975a1b8991f

common/defs.go

@@ -15,7 +15,10 @@
 package common
 
 import (
+	"path/filepath"
+
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/bootstrap"
 )
 
 var (
@@ -24,6 +27,13 @@ var (
 	cpPreserveSymlinks = pctx.VariableConfigMethod("cpPreserveSymlinks",
 		Config.CpPreserveSymlinksFlags)
 
+	androidbpCmd = filepath.Join(bootstrap.BinDir, "androidbp")
+	androidbp    = pctx.StaticRule("androidbp",
+		blueprint.RuleParams{
+			Command:     androidbpCmd + " $in $out",
+			Description: "androidbp $out",
+		})
+
 	// A phony rule that is not the built-in Ninja phony rule.  The built-in
 	// phony rule has special behavior that is sometimes not desired.  See the
 	// Ninja docs for more details.

common/module.go

@@ -17,6 +17,8 @@ package common
 import (
 	"path/filepath"
 	"runtime"
+	"sort"
+	"strings"
 
 	"android/soong/glob"
 
@@ -523,12 +525,15 @@ func (c *buildTargetSingleton) GenerateBuildActions(ctx blueprint.SingletonConte
 	checkbuildDeps := []string{}
 
 	dirModules := make(map[string][]string)
+	hasBPFile := make(map[string]bool)
+	bpFiles := []string{}
 
 	ctx.VisitAllModules(func(module blueprint.Module) {
 		if a, ok := module.(AndroidModule); ok {
 			blueprintDir := a.base().blueprintDir
 			installTarget := a.base().installTarget
 			checkbuildTarget := a.base().checkbuildTarget
+			bpFile := ctx.BlueprintFile(module)
 
 			if checkbuildTarget != "" {
 				checkbuildDeps = append(checkbuildDeps, checkbuildTarget)
@@ -538,6 +543,11 @@ func (c *buildTargetSingleton) GenerateBuildActions(ctx blueprint.SingletonConte
 			if installTarget != "" {
 				dirModules[blueprintDir] = append(dirModules[blueprintDir], installTarget)
 			}
+
+			if !hasBPFile[bpFile] {
+				hasBPFile[bpFile] = true
+				bpFiles = append(bpFiles, bpFile)
+			}
 		}
 	})
 
@@ -560,4 +570,43 @@ func (c *buildTargetSingleton) GenerateBuildActions(ctx blueprint.SingletonConte
 			Optional:  true,
 		})
 	}
+
+	// Create Android.bp->mk translation rules
+	androidMks := []string{}
+	srcDir := ctx.Config().(Config).SrcDir()
+	intermediatesDir := filepath.Join(ctx.Config().(Config).IntermediatesDir(), "androidmk")
+	sort.Strings(bpFiles)
+	for _, origBp := range bpFiles {
+		bpFile := filepath.Join(srcDir, origBp)
+		mkFile := filepath.Join(srcDir, filepath.Dir(origBp), "Android.mk")
+
+		files, err := Glob(ctx, intermediatesDir, mkFile, nil)
+		if err != nil {
+			ctx.Errorf("glob: %s", err.Error())
+			continue
+		}
+
+		// Existing Android.mk file, use that instead
+		if len(files) > 0 {
+			continue
+		}
+
+		transMk := filepath.Join("androidmk", "Android_"+strings.Replace(filepath.Dir(origBp), "/", "_", -1)+".mk")
+		ctx.Build(pctx, blueprint.BuildParams{
+			Rule:      androidbp,
+			Outputs:   []string{transMk},
+			Inputs:    []string{bpFile},
+			Implicits: []string{androidbpCmd},
+			Optional:  true,
+		})
+
+		androidMks = append(androidMks, transMk)
+	}
+
+	ctx.Build(pctx, blueprint.BuildParams{
+		Rule:      blueprint.Phony,
+		Outputs:   []string{"androidmk"},
+		Implicits: androidMks,
+		Optional:  true,
+	})
 }