Android 解決WebView多進程崩潰的方法

WebView.setDataDirectorySuffix(suffix);

Using WebView from more than one process at once with the same data directory is not supported. https://crbug.com/558377

1 com.android.webview.chromium.WebViewChromiumAwInit.startChromiumLocked(WebViewChromiumAwInit.java:63)
2 com.android.webview.chromium.WebViewChromiumAwInitForP.startChromiumLocked(WebViewChromiumAwInitForP.java:3)
3 com.android.webview.chromium.WebViewChromiumAwInit$3.run(WebViewChromiumAwInit.java:3)
4 android.os.Handler.handleCallback(Handler.java:873)
5 android.os.Handler.dispatchMessage(Handler.java:99)
6 android.os.Looper.loop(Looper.java:220)
7 android.app.ActivityThread.main(ActivityThread.java:7437)
8 java.lang.reflect.Method.invoke(Native Method)
9 com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:500)
10 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:865)

public class WebViewChromiumAwInit {
 protected void startChromiumLocked() {
   ...
   AwBrowserProcess.start();
   ... 
 }
}
public final class AwBrowserProcess {
 public static void start() {
   ...
   AwDataDirLock.lock(appContext);
}

abstract class AwDataDirLock {
 private static final String TAG = "AwDataDirLock";
 private static final String EXCLUSIVE_LOCK_FILE = "webview_data.lock";
 // This results in a maximum wait time of 1.5s
 private static final int LOCK_RETRIES = 16;
 private static final int LOCK_SLEEP_MS = 100;
 private static RandomAccessFile sLockFile;
 private static FileLock sExclusiveFileLock;

 static void lock(final Context appContext) {
  try (ScopedSysTraceEvent e1 = ScopedSysTraceEvent.scoped("AwDataDirLock.lock");
    StrictModeContext ignored = StrictModeContext.allowDiskWrites()) {
   if (sExclusiveFileLock != null) {
    // We have already called lock() and successfully acquired the lock in this process.
    // This shouldn't happen, but is likely to be the result of an app catching an
    // exception thrown during initialization and discarding it, causing us to later
    // attempt to initialize WebView again. There's no real advantage to failing the
    // locking code when this happens; we may as well count this as the lock being
    // acquired and let init continue (though the app may experience other problems
    // later).
    return;
   }
   // If we already called lock() but didn't succeed in getting the lock, it's possible the
   // app caught the exception and tried again later. As above, there's no real advantage
   // to failing here, so only open the lock file if we didn't already open it before.
   if (sLockFile == null) {
    String dataPath = PathUtils.getDataDirectory();
    File lockFile = new File(dataPath, EXCLUSIVE_LOCK_FILE);
    try {
   // Note that the file is kept open intentionally.
     sLockFile = new RandomAccessFile(lockFile, "rw");
    } catch (IOException e) {
    // Failing to create the lock file is always fatal; even if multiple processes
    // are using the same data directory we should always be able to access the file
    // itself.
     throw new RuntimeException("Failed to create lock file " + lockFile, e);
    }
   }
   // Android versions before 11 have edge cases where a new instance of an app process can
   // be started while an existing one is still in the process of being killed. This can
   // still happen on Android 11+ because the platform has a timeout for waiting, but it's
   // much less likely. Retry the lock a few times to give the old process time to fully go
   // away.
   for (int attempts = 1; attempts <= LOCK_RETRIES; ++attempts) {
    try {
     sExclusiveFileLock = sLockFile.getChannel().tryLock();
    } catch (IOException e) {
    // Older versions of Android incorrectly throw IOException when the flock()
    // call fails with EAGAIN, instead of returning null. Just ignore it.
    }
    if (sExclusiveFileLock != null) {
     // We got the lock; write out info for debugging.
     writeCurrentProcessInfo(sLockFile);
     return;
    }
    // If we're not out of retries, sleep and try again.
    if (attempts == LOCK_RETRIES) break;
    try {
     Thread.sleep(LOCK_SLEEP_MS);
    } catch (InterruptedException e) {
    }
   }
   // We failed to get the lock even after retrying.
   // Many existing apps rely on this even though it's known to be unsafe.
   // Make it fatal when on P for apps that target P or higher
   String error = getLockFailureReason(sLockFile);
   boolean dieOnFailure = Build.VERSION.SDK_INT >= Build.VERSION_CODES.P
     && appContext.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.P;
   if (dieOnFailure) {
    throw new RuntimeException(error);
   } else {
    Log.w(TAG, error);
   }
  }
 }

 private static void writeCurrentProcessInfo(final RandomAccessFile file) {
  try {
   // Truncate the file first to get rid of old data.
   file.setLength(0);
   file.writeInt(Process.myPid());
   file.writeUTF(ContextUtils.getProcessName());
  } catch (IOException e) {
   // Don't crash just because something failed here, as it's only for debugging.
   Log.w(TAG, "Failed to write info to lock file", e);
  }
 }

 private static String getLockFailureReason(final RandomAccessFile file) {
  final StringBuilder error = new StringBuilder("Using WebView from more than one process at "
    + "once with the same data directory is not supported. https://crbug.com/558377 "
    + ": Current process ");
  error.append(ContextUtils.getProcessName());
  error.append(" (pid ").append(Process.myPid()).append("), lock owner ");
  try {
   int pid = file.readInt();
   String processName = file.readUTF();
   error.append(processName).append(" (pid ").append(pid).append(")");
   // Check the status of the pid holding the lock by sending it a null signal.
   // This doesn't actually send a signal, just runs the kernel access checks.
   try {
    Os.kill(pid, 0);
    // No exception means the process exists and has the same uid as us, so is
    // probably an instance of the same app. Leave the message alone.
   } catch (ErrnoException e) {
    if (e.errno == OsConstants.ESRCH) {
     // pid did not exist - the lock should have been released by the kernel,
     // so this process info is probably wrong.
     error.append(" doesn't exist!");
    } else if (e.errno == OsConstants.EPERM) {
     // pid existed but didn't have the same uid as us.
     // Most likely the pid has just been recycled for a new process
     error.append(" pid has been reused!");
    } else {
     // EINVAL is the only other documented return value for kill(2) and should never
     // happen for signal 0, so just complain generally.
     error.append(" status unknown!");
    }
   }
  } catch (IOException e) {
   // We'll get IOException if we failed to read the pid and process name; e.g. if the
   // lockfile is from an old version of WebView or an IO error occurred somewhere.
   error.append(" unknown");
  }
  return error.toString();
 }
}

private static void handleWebviewDir(Context context) {
  if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P) {
   return;
  }
  try {
   String suffix = "";
   String processName = getProcessName(context);
   if (!TextUtils.equals(context.getPackageName(), processName)) {//判斷不等於默認進程名稱
    suffix = TextUtils.isEmpty(processName) ? context.getPackageName() : processName;
    WebView.setDataDirectorySuffix(suffix);
    suffix = "_" + suffix;
   }
   tryLockOrRecreateFile(context,suffix);
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 @TargetApi(Build.VERSION_CODES.P)
 private static void tryLockOrRecreateFile(Context context,String suffix) {
  String sb = context.getDataDir().getAbsolutePath() +
    "/app_webview"+suffix+"/webview_data.lock";
  File file = new File(sb);
  if (file.exists()) {
   try {
    FileLock tryLock = new RandomAccessFile(file, "rw").getChannel().tryLock();
    if (tryLock != null) {
     tryLock.close();
    } else {
     createFile(file, file.delete());
    }
   } catch (Exception e) {
    e.printStackTrace();
    boolean deleted = false;
    if (file.exists()) {
     deleted = file.delete();
    }
    createFile(file, deleted);
   }
  }
 }

 private static void createFile(File file, boolean deleted){
  try {
   if (deleted && !file.exists()) {
    file.createNewFile();
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
 }