Upstream: Version WebAPK runtime library

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkServiceFactory.java

Index: chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkServiceFactory.java
diff --git a/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkServiceFactory.java b/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkServiceFactory.java
index d977edbab65e3f1f13d11a26ef47fe2b94dd8f4a..61a43c40ddfba1e91879d261622fc77817cfc16b 100644
--- a/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkServiceFactory.java
+++ b/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkServiceFactory.java
@@ -7,6 +7,9 @@ package org.chromium.webapk.shell_apk;
 import android.app.Service;
 import android.content.Context;
 import android.content.Intent;
+import android.content.SharedPreferences;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.util.Log;
@@ -15,6 +18,7 @@ import org.chromium.webapk.lib.common.WebApkUtils;
 
 import java.io.File;
 import java.lang.reflect.Constructor;
+import java.util.Scanner;
 
 /**
  * Shell class for services provided by WebAPK to Chrome. Extracts code with implementation of
@@ -29,6 +33,23 @@ public class WebApkServiceFactory extends Service {
     private static final String WEBAPK_SERVICE_IMPL_CLASS_NAME =
             "org.chromium.webapk.lib.runtime_library.WebApkServiceImpl";
 
+    /**
+     * Name of the shared preferences file.
+     */
+    private static final String PREF_PACKAGE = "org.chromium.webapk.shell_apk";
+
+    /**
+     * Name of the shared preference for Chrome's version code.
+     */
+    private static final String REMOTE_VERSION_CODE_PREF =
+            "org.chromium.webapk.shell_apk.version_code";
+
+    /**
+     * Name of the shared preference for the version number of the dynamically loaded dex.
+     */
+    private static final String RUNTIME_DEX_VERSION_PREF =
+            "org.chromium.webapk.shell_apk.dex_version";
+
     private static final String KEY_SMALL_ICON_ID = "small_icon_id";
 
     /*
@@ -62,7 +83,7 @@ public class WebApkServiceFactory extends Service {
     }
 
     /**
-     * Gets / creates ClassLaoder for loading {@link WEBAPK_SERVICE_IMPL_CLASS_NAME}.
+     * Gets / creates ClassLoader for loading {@link WEBAPK_SERVICE_IMPL_CLASS_NAME}.
      * @param context WebAPK's context.
      * @return The ClassLoader.
      */
@@ -85,10 +106,82 @@ public class WebApkServiceFactory extends Service {
             return null;
         }
 
+        SharedPreferences preferences = context.getSharedPreferences(PREF_PACKAGE, MODE_PRIVATE);
+
+        int runtimeDexVersion = preferences.getInt(RUNTIME_DEX_VERSION_PREF, -1);
+        int newRuntimeDexVersion = checkForNewRuntimeDexVersion(preferences, remoteContext);
+        if (newRuntimeDexVersion == -1) {
+            newRuntimeDexVersion = runtimeDexVersion;
+        }
         File localDexDir = context.getDir("dex", Context.MODE_PRIVATE);
+        if (newRuntimeDexVersion != runtimeDexVersion) {
+            Log.w(TAG, "Delete cached dex files.");
+            DexLoader.deleteCachedDexes(localDexDir);
+        }
+
+        String dexAssetName = WebApkUtils.getRuntimeDexName(newRuntimeDexVersion);
         File remoteDexFile =
-                new File(remoteContext.getDir("dex", Context.MODE_PRIVATE), "web_apk.dex");
-        return DexLoader.load(remoteContext, "web_apk.dex", WEBAPK_SERVICE_IMPL_CLASS_NAME,
+                new File(remoteContext.getDir("dex", Context.MODE_PRIVATE), dexAssetName);
+        return DexLoader.load(remoteContext, dexAssetName, WEBAPK_SERVICE_IMPL_CLASS_NAME,
                 remoteDexFile, localDexDir);
     }
+
+    /**
+     * Checks if there is a new "runtime dex" version number. If there is a new version number,
+     * updates SharedPreferences.
+     * @param preferences WebAPK's SharedPreferences.
+     * @param remoteContext
+     * @return The new "runtime dex" version number. -1 if there is no new version number.
+     */
+    private static int checkForNewRuntimeDexVersion(
+            SharedPreferences preferences, Context remoteContext) {
+        // The "runtime dex" version only changes when {@link remoteContext}'s APK version code
+        // changes. Checking the APK's version code is less expensive than reading from the APK's
+        // assets.
+        PackageInfo remotePackageInfo = null;
+        try {
+            remotePackageInfo = remoteContext.getPackageManager().getPackageInfo(
+                    remoteContext.getPackageName(), 0);
+        } catch (PackageManager.NameNotFoundException e) {
+            Log.e(TAG, "Failed to get remote package info.");
+            return -1;
+        }
+
+        int cachedRemoteVersionCode = preferences.getInt(REMOTE_VERSION_CODE_PREF, -1);
+        if (cachedRemoteVersionCode == remotePackageInfo.versionCode) {
+            return -1;
+        }
+
+        int runtimeDexVersion = readAssetContentsToInt(remoteContext, "webapk_dex_version.txt");
+        SharedPreferences.Editor editor = preferences.edit();
+        editor.putInt(REMOTE_VERSION_CODE_PREF, remotePackageInfo.versionCode);
+        editor.putInt(RUNTIME_DEX_VERSION_PREF, runtimeDexVersion);
+        editor.apply();
+        return runtimeDexVersion;
+    }
+
+    /**
+     * Returns the first integer in an asset file's contents.
+     * @param context
+     * @param assetName The name of the asset.
+     * @return The first integer.
+     */
+    private static int readAssetContentsToInt(Context context, String assetName) {
+        Scanner scanner = null;
+        int value = -1;
+        try {
+            scanner = new Scanner(context.getAssets().open(assetName));
+            value = scanner.nextInt();
+            scanner.close();
+        } catch (Exception e) {
+        } finally {
+            if (scanner != null) {
+                try {
+                    scanner.close();
+                } catch (Exception e) {
+                }
+            }
+        }
+        return value;
+    }
 }