Get mojo_shell building inside chromium checkout.

mojo/shell/android/apk/src/org/chromium/mojo/shell/FileHelper.java

Index: mojo/shell/android/apk/src/org/chromium/mojo/shell/FileHelper.java
diff --git a/mojo/shell/android/apk/src/org/chromium/mojo/shell/FileHelper.java b/mojo/shell/android/apk/src/org/chromium/mojo/shell/FileHelper.java
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index 0000000000000000000000000000000000000000..c455251559f35f3d5cece6872935792b9878cedb
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+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.mojo.shell;
+
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.util.Log;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.FilenameFilter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+/**
+ * Helper methods for file extraction from APK assets and zip archives.
+ */
+class FileHelper {
+    public static final String TAG = "MojoFileHelper";
+
+    // Size of the buffer used in streaming file operations.
+    private static final int BUFFER_SIZE = 1024 * 1024;
+    // Prefix used when naming temporary files.
+    private static final String TEMP_FILE_PREFIX = "temp-";
+    // Prefix used when naming timestamp files.
+    private static final String TIMESTAMP_PREFIX = "asset_timestamp-";
+
+    /**
+     * Looks for a timestamp file on disk that indicates the version of the APK that the resource
+     * assets were extracted from. Returns null if a timestamp was found and it indicates that the
+     * resources match the current APK. Otherwise returns a String that represents the filename of a
+     * timestamp to create.
+     */
+    private static String checkAssetTimestamp(Context context, File outputDir) {
+        PackageManager pm = context.getPackageManager();
+        PackageInfo pi = null;
+
+        try {
+            pi = pm.getPackageInfo(context.getPackageName(), 0);
+        } catch (PackageManager.NameNotFoundException e) {
+            return TIMESTAMP_PREFIX;
+        }
+
+        if (pi == null) {
+            return TIMESTAMP_PREFIX;
+        }
+
+        String expectedTimestamp = TIMESTAMP_PREFIX + pi.versionCode + "-" + pi.lastUpdateTime;
+
+        String[] timestamps = outputDir.list(new FilenameFilter() {
+            @Override
+            public boolean accept(File dir, String name) {
+                return name.startsWith(TIMESTAMP_PREFIX);
+            }
+        });
+
+        if (timestamps.length != 1) {
+            // If there's no timestamp, nuke to be safe as we can't tell the age of the files.
+            // If there's multiple timestamps, something's gone wrong so nuke.
+            return expectedTimestamp;
+        }
+
+        if (!expectedTimestamp.equals(timestamps[0])) {
+            return expectedTimestamp;
+        }
+
+        // Timestamp file is already up-to date.
+        return null;
+    }
+
+    public static File extractFromAssets(Context context, String assetName, File outputDirectory,
+            boolean useTempFile) throws IOException, FileNotFoundException {
+        String timestampToCreate = null;
+        if (!useTempFile) {
+            timestampToCreate = checkAssetTimestamp(context, outputDirectory);
+            if (timestampToCreate != null) {
+                for (File child : outputDirectory.listFiles()) {
+                    deleteRecursively(child);
+                }
+            }
+        }
+
+        File outputFile;
+        if (useTempFile) {
+            // Make the original filename part of the temp file name.
+            // TODO(ppi): do we need to sanitize the suffix?
+            String suffix = "-" + assetName;
+            outputFile = File.createTempFile(TEMP_FILE_PREFIX, suffix, outputDirectory);
+        } else {
+            outputFile = new File(outputDirectory, assetName);
+            if (outputFile.exists()) {
+                return outputFile;
+            }
+        }
+
+        BufferedInputStream inputStream = new BufferedInputStream(
+                context.getAssets().open(assetName));
+        try {
+            writeStreamToFile(inputStream, outputFile);
+        } finally {
+            inputStream.close();
+        }
+
+        if (timestampToCreate != null) {
+            try {
+                new File(outputDirectory, timestampToCreate).createNewFile();
+            } catch (IOException e) {
+                // In the worst case we don't write a timestamp, so we'll re-extract the asset next
+                // time.
+                Log.w(TAG, "Failed to write asset timestamp!");
+            }
+        }
+
+        return outputFile;
+    }
+
+    /**
+     * Extracts the file of the given extension from the archive. Throws FileNotFoundException if no
+     * matching file is found.
+     */
+    static File extractFromArchive(File archive, String suffixToMatch,
+            File outputDirectory) throws IOException, FileNotFoundException {
+        ZipInputStream zip = new ZipInputStream(new BufferedInputStream(new FileInputStream(
+                archive)));
+        ZipEntry entry;
+        while ((entry = zip.getNextEntry()) != null) {
+            if (entry.getName().endsWith(suffixToMatch)) {
+                // Make the original filename part of the temp file name.
+                // TODO(ppi): do we need to sanitize the suffix?
+                String suffix = "-" + new File(entry.getName()).getName();
+                File extractedFile = File.createTempFile(TEMP_FILE_PREFIX, suffix,
+                        outputDirectory);
+                writeStreamToFile(zip, extractedFile);
+                zip.close();
+                return extractedFile;
+            }
+        }
+        zip.close();
+        throw new FileNotFoundException();
+    }
+
+    /**
+     * Deletes a file or directory. Directory will be deleted even if not empty.
+     */
+    static void deleteRecursively(File file) {
+        if (file.isDirectory()) {
+            for (File child : file.listFiles()) {
+                deleteRecursively(child);
+            }
+        }
+        if (!file.delete()) {
+            Log.w(TAG, "Unable to delete file: " + file.getAbsolutePath());
+        }
+    }
+
+    private static void writeStreamToFile(InputStream inputStream, File outputFile)
+            throws IOException {
+        byte[] buffer = new byte[BUFFER_SIZE];
+        OutputStream outputStream = new BufferedOutputStream(new FileOutputStream(outputFile));
+        try {
+            int read;
+            while ((read = inputStream.read(buffer, 0, BUFFER_SIZE)) > 0) {
+                outputStream.write(buffer, 0, read);
+            }
+        } finally {
+            outputStream.close();
+        }
+    }
+}