Move sharding functions for reuse

Move shardPaths and shardTests to android.ShardPaths and
android.ShardStrings for reuse in other packages.

Test: m checkbuild
Change-Id: I868802872c73616b80f56cbf11f959c01a8b793a

4 files changed, 5 insertions, 122 deletions

diff --git a/java/aapt2.go b/java/aapt2.go
index f0eb99cee..cfe0deab1 100644
--- a/java/aapt2.go
+++ b/java/aapt2.go
@@ -63,7 +63,7 @@ var aapt2CompileRule = pctx.AndroidStaticRule("aapt2Compile",
 func aapt2Compile(ctx android.ModuleContext, dir android.Path, paths android.Paths,
 	flags []string) android.WritablePaths {
 
-	shards := shardPaths(paths, AAPT2_SHARD_SIZE)
+	shards := android.ShardPaths(paths, AAPT2_SHARD_SIZE)
 
 	ret := make(android.WritablePaths, 0, len(paths))
 
diff --git a/java/java.go b/java/java.go
index ce72c2760..f7b0f53ba 100644
--- a/java/java.go
+++ b/java/java.go
@@ -580,18 +580,6 @@ func hasSrcExt(srcs []string, ext string) bool {
 	return false
 }
 
-func shardPaths(paths android.Paths, shardSize int) []android.Paths {
-	ret := make([]android.Paths, 0, (len(paths)+shardSize-1)/shardSize)
-	for len(paths) > shardSize {
-		ret = append(ret, paths[0:shardSize])
-		paths = paths[shardSize:]
-	}
-	if len(paths) > 0 {
-		ret = append(ret, paths)
-	}
-	return ret
-}
-
 func (j *Module) hasSrcExt(ext string) bool {
 	return hasSrcExt(j.properties.Srcs, ext)
 }
@@ -1156,7 +1144,7 @@ func (j *Module) compile(ctx android.ModuleContext, aaptSrcJar android.Path) {
 			shardSize := int(*(j.properties.Javac_shard_size))
 			var shardSrcs []android.Paths
 			if len(uniqueSrcFiles) > 0 {
-				shardSrcs = shardPaths(uniqueSrcFiles, shardSize)
+				shardSrcs = android.ShardPaths(uniqueSrcFiles, shardSize)
 				for idx, shardSrc := range shardSrcs {
 					classes := j.compileJavaClasses(ctx, jarName, idx, shardSrc,
 						nil, flags, extraJarDeps)
diff --git a/java/robolectric.go b/java/robolectric.go
index dbf54c9b3..b7646eb45 100644
--- a/java/robolectric.go
+++ b/java/robolectric.go
@@ -123,25 +123,6 @@ func (r *robolectricTest) GenerateAndroidBuildActions(ctx android.ModuleContext)
 	}
 }
 
-func shardTests(paths []string, shards int) [][]string {
-	if shards > len(paths) {
-		shards = len(paths)
-	}
-	if shards == 0 {
-		return nil
-	}
-	ret := make([][]string, 0, shards)
-	shardSize := (len(paths) + shards - 1) / shards
-	for len(paths) > shardSize {
-		ret = append(ret, paths[0:shardSize])
-		paths = paths[shardSize:]
-	}
-	if len(paths) > 0 {
-		ret = append(ret, paths)
-	}
-	return ret
-}
-
 func generateRoboTestConfig(ctx android.ModuleContext, outputFile android.WritablePath, instrumentedApp *AndroidApp) {
 	manifest := instrumentedApp.mergedManifestFile
 	resourceApk := instrumentedApp.outputFile
@@ -183,7 +164,9 @@ func (r *robolectricTest) AndroidMkEntries() android.AndroidMkEntries {
 	entries.ExtraFooters = []android.AndroidMkExtraFootersFunc{
 		func(w io.Writer, name, prefix, moduleDir string, entries *android.AndroidMkEntries) {
 			if s := r.robolectricProperties.Test_options.Shards; s != nil && *s > 1 {
-				shards := shardTests(r.tests, int(*s))
+				numShards := int(*s)
+				shardSize := (len(r.tests) + numShards - 1) / numShards
+				shards := android.ShardStrings(r.tests, shardSize)
 				for i, shard := range shards {
 					r.writeTestRunner(w, name, "Run"+name+strconv.Itoa(i), shard)
 				}
diff --git a/java/robolectric_test.go b/java/robolectric_test.go
deleted file mode 100644
index e89c6e74c..000000000
--- a/java/robolectric_test.go
+++ /dev/null
@@ -1,88 +0,0 @@
-// Copyright 2019 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 java
-
-import (
-	"reflect"
-	"testing"
-)
-
-func Test_shardTests(t *testing.T) {
-	type args struct {
-		paths  []string
-		shards int
-	}
-	tests := []struct {
-		name string
-		args args
-		want [][]string
-	}{
-		{
-			name: "empty",
-			args: args{
-				paths:  nil,
-				shards: 1,
-			},
-			want: [][]string(nil),
-		},
-		{
-			name: "too many shards",
-			args: args{
-				paths:  []string{"a", "b"},
-				shards: 3,
-			},
-			want: [][]string{{"a"}, {"b"}},
-		},
-		{
-			name: "single shard",
-			args: args{
-				paths:  []string{"a", "b"},
-				shards: 1,
-			},
-			want: [][]string{{"a", "b"}},
-		},
-		{
-			name: "shard per input",
-			args: args{
-				paths:  []string{"a", "b", "c"},
-				shards: 3,
-			},
-			want: [][]string{{"a"}, {"b"}, {"c"}},
-		},
-		{
-			name: "balanced shards",
-			args: args{
-				paths:  []string{"a", "b", "c", "d"},
-				shards: 2,
-			},
-			want: [][]string{{"a", "b"}, {"c", "d"}},
-		},
-		{
-			name: "unbalanced shards",
-			args: args{
-				paths:  []string{"a", "b", "c"},
-				shards: 2,
-			},
-			want: [][]string{{"a", "b"}, {"c"}},
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if got := shardTests(tt.args.paths, tt.args.shards); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("shardTests() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}