Revert of 🐸 Check for 0-length files in ResourceExtractor

base/android/java/src/org/chromium/base/ResourceExtractor.java

Index: base/android/java/src/org/chromium/base/ResourceExtractor.java
diff --git a/base/android/java/src/org/chromium/base/ResourceExtractor.java b/base/android/java/src/org/chromium/base/ResourceExtractor.java
index eb66edf38010dac5d94a181e8625a9bef76fc385..458e266b48c98f15e8d4d559058ec9312a663e2d 100644
--- a/base/android/java/src/org/chromium/base/ResourceExtractor.java
+++ b/base/android/java/src/org/chromium/base/ResourceExtractor.java
@@ -6,7 +6,6 @@ package org.chromium.base;
 
 import android.annotation.TargetApi;
 import android.content.Context;
-import android.content.SharedPreferences;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.os.AsyncTask;
@@ -19,6 +18,7 @@ import org.chromium.base.annotations.SuppressFBWarnings;
 
 import java.io.File;
 import java.io.FileOutputStream;
+import java.io.FilenameFilter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -26,8 +26,6 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
-import java.util.zip.ZipEntry;
-import java.util.zip.ZipFile;
 
 /**
  * Handles extracting the necessary resources bundled in an APK and moving them to a location on
@@ -39,7 +37,6 @@ public class ResourceExtractor {
     private static final String ICU_DATA_FILENAME = "icudtl.dat";
     private static final String V8_NATIVES_DATA_FILENAME = "natives_blob.bin";
     private static final String V8_SNAPSHOT_DATA_FILENAME = "snapshot_blob.bin";
-    private static final String APP_VERSION_PREF = "org.chromium.base.ResourceExtractor.Version";
 
     private static ResourceEntry[] sResourcesToExtract = new ResourceEntry[0];
 
@@ -74,15 +71,21 @@ public class ResourceExtractor {
                 while ((count = is.read(buffer, 0, BUFFER_SIZE)) != -1) {
                     os.write(buffer, 0, count);
                 }
+                os.flush();
+
+                // Ensure something reasonable was written.
+                if (outFile.length() == 0) {
+                    throw new IOException(outFile + " extracted with 0 length!");
+                }
             } finally {
                 try {
-                    if (os != null) {
-                        os.close();
-                    }
-                } finally {
                     if (is != null) {
                         is.close();
                     }
+                } finally {
+                    if (os != null) {
+                        os.close();
+                    }
                 }
             }
         }
@@ -94,29 +97,24 @@ public class ResourceExtractor {
                 return;
             }
 
+            String timestampFile = null;
             beginTraceSection("checkPakTimeStamp");
-            long curAppVersion = getApplicationVersion();
-            SharedPreferences sharedPrefs = ContextUtils.getAppSharedPreferences();
-            long prevAppVersion = sharedPrefs.getLong(APP_VERSION_PREF, 0);
-            boolean versionChanged = curAppVersion != prevAppVersion;
-            endTraceSection();
-
-            if (versionChanged) {
+            try {
+                timestampFile = checkPakTimestamp(outputDir);
+            } finally {
+                endTraceSection();
+            }
+            if (timestampFile != null) {
                 deleteFiles();
-                // Use the version only to see if files should be deleted, not to skip extraction.
-                // We've seen files be corrupted, so always attempt extraction.
-                // http://crbug.com/606413
-                sharedPrefs.edit().putLong(APP_VERSION_PREF, curAppVersion).apply();
             }
 
             beginTraceSection("WalkAssets");
             byte[] buffer = new byte[BUFFER_SIZE];
             try {
+                // Extract all files that don't already exist.
                 for (ResourceEntry entry : sResourcesToExtract) {
                     File output = new File(outputDir, entry.extractedFileName);
-                    // TODO(agrieve): It would be better to check that .length == expectedLength.
-                    //     http://crbug.com/606413
-                    if (output.length() != 0) {
+                    if (output.exists()) {
                         continue;
                     }
                     beginTraceSection("ExtractResource");
@@ -139,6 +137,17 @@ public class ResourceExtractor {
             } finally {
                 endTraceSection(); // WalkAssets
             }
+
+            // Finished, write out a timestamp file if we need to.
+            if (timestampFile != null) {
+                try {
+                    new File(outputDir, timestampFile).createNewFile();
+                } catch (IOException e) {
+                    // Worst case we don't write a timestamp, so we'll re-extract the resource
+                    // paks next start up.
+                    Log.w(TAG, "Failed to write resource pak timestamp!");
+                }
+            }
         }
 
         @Override
@@ -180,25 +189,42 @@ public class ResourceExtractor {
         // Note that we do this to avoid adding a BroadcastReceiver on
         // android.content.Intent#ACTION_PACKAGE_CHANGED as that causes process churn
         // on (re)installation of *all* APK files.
-        private long getApplicationVersion() {
+        private String checkPakTimestamp(File outputDir) {
+            final String timestampPrefix = "pak_timestamp-";
             PackageManager pm = mContext.getPackageManager();
+            PackageInfo pi = null;
+
             try {
-                PackageInfo pi = pm.getPackageInfo(mContext.getPackageName(), 0);
-                if (pi != null && pi.versionCode > 1) {
-                    return pi.versionCode;
-                }
+                pi = pm.getPackageInfo(mContext.getPackageName(), 0);
             } catch (PackageManager.NameNotFoundException e) {
-                throw new RuntimeException(e);
+                return timestampPrefix;
             }
-            // For dev builds, use the APK's CRC-32.
-            try {
-                ZipFile apk = new ZipFile(mContext.getApplicationInfo().sourceDir);
-                ZipEntry manifestEntry = apk.getEntry("META-INF/MANIFEST.MF");
-                apk.close();
-                return manifestEntry.getCrc();
-            } catch (IOException e) {
-                throw new RuntimeException(e);
+
+            if (pi == null) {
+                return timestampPrefix;
+            }
+
+            String expectedTimestamp = timestampPrefix + pi.versionCode + "-" + pi.lastUpdateTime;
+
+            String[] timestamps = outputDir.list(new FilenameFilter() {
+                @Override
+                public boolean accept(File dir, String name) {
+                    return name.startsWith(timestampPrefix);
+                }
+            });
+
+            if (timestamps == null || 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;
         }
 
         @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)