1 files changed, 108 insertions, 0 deletions
diff --git a/src/tools/ak/mindex/mindex.go b/src/tools/ak/mindex/mindex.go
new file mode 100644
index 0000000..9bdbefa
--- /dev/null
+++ b/src/tools/ak/mindex/mindex.go
@@ -0,0 +1,108 @@
+// Copyright 2018 The Bazel Authors. 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 mindex writes a minimal dex into a file.
+// It encodes the minimal necessary fields to pass muster with the android runtime.
+package mindex
+
+import (
+	"flag"
+	"io/ioutil"
+	"log"
+	"sync"
+
+	"src/tools/ak/types"
+)
+
+var (
+	// Cmd defines the command to run mindex
+	Cmd = types.Command{
+		Init: Init,
+		Run:  Run,
+		Desc: desc,
+		Flags: []string{
+			"out",
+		},
+	}
+
+	// Variables that hold flag values
+	out      string
+	initOnce sync.Once
+
+	// see https://android.googlesource.com/platform/art/+/android-5.0.1_r1/runtime/dex_file.h
+
+	minDex = []byte{
+		0x64, 0x65, 0x78, 0x0A, // 0x00: Dex magic
+		0x30, 0x33, 0x35, 0x00, // 0x04: Dex version
+		0x44, 0x0E, 0xC1, 0x0F, // 0x08: Adler32 checksum
+		0x8B, 0x9B, 0x61, 0xEA, // 0x0C: Sha1 digest
+		0xC1, 0x7F, 0x94, 0x5A, // 0x10: Sha1 digest cont.
+		0xE9, 0xC0, 0x8A, 0x70, // 0x14: Sha1 digest cont.
+		0xFD, 0xED, 0x4F, 0x53, // 0x18: Sha1 digest cont.
+		0x0F, 0x10, 0x51, 0x75, // 0x1C: Sha1 digest cont.
+
+		// Header
+		0x8C, 0x00, 0x00, 0x00, // 0x20: Files size
+		0x70, 0x00, 0x00, 0x00, // 0x24: Header size
+		0x78, 0x56, 0x34, 0x12, // 0x28: Endian tag
+		0x00, 0x00, 0x00, 0x00, // 0x2C: Link size
+		0x00, 0x00, 0x00, 0x00, // 0x30: Link offset
+		0x70, 0x00, 0x00, 0x00, // 0x34: Map offset
+		0x00, 0x00, 0x00, 0x00, // 0x38: String ids size
+		0x00, 0x00, 0x00, 0x00, // 0x3C: String ids offset
+		0x00, 0x00, 0x00, 0x00, // 0x40: Type ids size
+		0x00, 0x00, 0x00, 0x00, // 0x44: Type ids offset
+		0x00, 0x00, 0x00, 0x00, // 0x48: Proto ids size
+		0x00, 0x00, 0x00, 0x00, // 0x4C: Proto ids offset
+		0x00, 0x00, 0x00, 0x00, // 0x50: Field ids size
+		0x00, 0x00, 0x00, 0x00, // 0x54: Field ids offset
+		0x00, 0x00, 0x00, 0x00, // 0x58: Method ids size
+		0x00, 0x00, 0x00, 0x00, // 0x5C: Method ids offset
+		0x00, 0x00, 0x00, 0x00, // 0x60: Class defs size
+		0x00, 0x00, 0x00, 0x00, // 0x64: Class defs offset
+		0x1C, 0x00, 0x00, 0x00, // 0x68: Data size
+		0x70, 0x00, 0x00, 0x00, // 0x6C: Data offset
+
+		// Data
+		0x02, 0x00, 0x00, 0x00, // 0x70: Map list size (header and map list)
+		0x00, 0x00, 0x00, 0x00, // 0x74: kDexTypeHeaderItem
+		0x01, 0x00, 0x00, 0x00, // 0x78: HeaderItem count
+		0x00, 0x00, 0x00, 0x00, // 0x7C: Offset 0x00
+		0x00, 0x10, 0x00, 0x00, // 0x80: kDexTypeMapList
+		0x01, 0x00, 0x00, 0x00, // 0x84: MapList count
+		0x70, 0x00, 0x00, 0x00, // 0x88: Offset 0x70
+	}
+)
+
+// Init initializes mindex.
+func Init() {
+	initOnce.Do(func() {
+		flag.StringVar(&out, "out", "", "Path to output.")
+	})
+}
+
+func desc() string {
+	return "Mindex writes the smallest possible dex to a file."
+}
+
+// Run is the entry point for mindex.
+func Run() {
+	if out == "" {
+		log.Fatal("Flags -out must be specified.")
+	}
+
+	if err := ioutil.WriteFile(out, minDex, 0655); err != nil {
+		log.Fatalf("Error writing minimal dex %v", err)
+	}
+}