Implement merge_zips

For merging .zip and/or .jar files

Bug: 64691570
Test: merge_zips merged.zip in1.zip in2.zip
Change-Id: I9a080d25b92a506c9b5451670c4786895b2722ab

2 files changed, 198 insertions, 0 deletions

diff --git a/cmd/merge_zips/Android.bp b/cmd/merge_zips/Android.bp
new file mode 100644
index 00000000..ace079dc
--- /dev/null
+++ b/cmd/merge_zips/Android.bp
@@ -0,0 +1,25 @@
+// 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.
+
+blueprint_go_binary {
+    name: "merge_zips",
+    deps: [
+      "android-archive-zip",
+      "soong-jar",
+    ],
+    srcs: [
+        "merge_zips.go",
+    ],
+}
+
diff --git a/cmd/merge_zips/merge_zips.go b/cmd/merge_zips/merge_zips.go
new file mode 100644
index 00000000..e1780360
--- /dev/null
+++ b/cmd/merge_zips/merge_zips.go
@@ -0,0 +1,173 @@
+// 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 main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"sort"
+	"strings"
+
+	"android/soong/jar"
+	"android/soong/third_party/zip"
+)
+
+var (
+	sortEntries = flag.Bool("s", false, "sort entries (defaults to the order from the input zip files)")
+	sortJava    = flag.Bool("j", false, "sort zip entries using jar ordering (META-INF first)")
+)
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintln(os.Stderr, "usage: merge_zips [-j] output [inputs...]")
+		flag.PrintDefaults()
+	}
+
+	// parse args
+	flag.Parse()
+	args := flag.Args()
+	if len(args) < 2 {
+		flag.Usage()
+		os.Exit(1)
+	}
+	outputPath := args[0]
+	inputs := args[1:]
+
+	log.SetFlags(log.Lshortfile)
+
+	// make writer
+	output, err := os.Create(outputPath)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer output.Close()
+	writer := zip.NewWriter(output)
+	defer func() {
+		err := writer.Close()
+		if err != nil {
+			log.Fatal(err)
+		}
+	}()
+
+	// make readers
+	readers := []namedZipReader{}
+	for _, input := range inputs {
+		reader, err := zip.OpenReader(input)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer reader.Close()
+		namedReader := namedZipReader{path: input, reader: reader}
+		readers = append(readers, namedReader)
+	}
+
+	// do merge
+	if err := mergeZips(readers, writer, *sortEntries, *sortJava); err != nil {
+		log.Fatal(err)
+	}
+}
+
+// a namedZipReader reads a .zip file and can say which file it's reading
+type namedZipReader struct {
+	path   string
+	reader *zip.ReadCloser
+}
+
+// a zipEntryPath refers to a file contained in a zip
+type zipEntryPath struct {
+	zipName   string
+	entryName string
+}
+
+func (p zipEntryPath) String() string {
+	return p.zipName + "/" + p.entryName
+}
+
+// a zipEntry knows the location and content of a file within a zip
+type zipEntry struct {
+	path    zipEntryPath
+	content *zip.File
+}
+
+// a fileMapping specifies to copy a zip entry from one place to another
+type fileMapping struct {
+	source zipEntry
+	dest   string
+}
+
+func mergeZips(readers []namedZipReader, writer *zip.Writer, sortEntries bool, sortJava bool) error {
+
+	mappingsByDest := make(map[string]fileMapping, 0)
+	orderedMappings := []fileMapping{}
+
+	for _, namedReader := range readers {
+		for _, file := range namedReader.reader.File {
+			// check for other files or directories destined for the same path
+			dest := file.Name
+			mapKey := dest
+			if strings.HasSuffix(mapKey, "/") {
+				mapKey = mapKey[:len(mapKey)-1]
+			}
+			existingMapping, exists := mappingsByDest[mapKey]
+
+			// make a new entry to add
+			source := zipEntry{path: zipEntryPath{zipName: namedReader.path, entryName: file.Name}, content: file}
+			newMapping := fileMapping{source: source, dest: dest}
+
+			// handle duplicates
+			if exists {
+				wasDir := existingMapping.source.content.FileHeader.FileInfo().IsDir()
+				isDir := newMapping.source.content.FileHeader.FileInfo().IsDir()
+				if !wasDir || !isDir {
+					return fmt.Errorf("Duplicate path %v found in %v and %v\n",
+						dest, existingMapping.source.path, newMapping.source.path)
+				}
+			}
+
+			// save entry
+			mappingsByDest[mapKey] = newMapping
+			orderedMappings = append(orderedMappings, newMapping)
+		}
+
+	}
+
+	if sortJava {
+		jarSort(orderedMappings)
+	} else if sortEntries {
+		alphanumericSort(orderedMappings)
+	}
+
+	for _, entry := range orderedMappings {
+		if err := writer.CopyFrom(entry.source.content, entry.dest); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func jarSort(files []fileMapping) {
+	sort.SliceStable(files, func(i, j int) bool {
+		return jar.EntryNamesLess(files[i].dest, files[j].dest)
+	})
+}
+
+func alphanumericSort(files []fileMapping) {
+	sort.SliceStable(files, func(i, j int) bool {
+		return files[i].dest < files[j].dest
+	})
+}