Refactoring ChildProcessConnection.

content/public/android/java/src/org/chromium/content/browser/ChildProcessConnectionImpl.java

Index: content/public/android/java/src/org/chromium/content/browser/ChildProcessConnectionImpl.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ChildProcessConnectionImpl.java b/content/public/android/java/src/org/chromium/content/browser/ChildProcessConnectionImpl.java
deleted file mode 100644
index 710741b69c86a045512bf88f0459e6b9fd7934e7..0000000000000000000000000000000000000000
--- a/content/public/android/java/src/org/chromium/content/browser/ChildProcessConnectionImpl.java
+++ /dev/null
@@ -1,588 +0,0 @@
-// Copyright 2013 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.content.browser;
-
-import android.content.ComponentName;
-import android.content.Context;
-import android.content.Intent;
-import android.content.ServiceConnection;
-import android.content.pm.PackageManager;
-import android.content.pm.ServiceInfo;
-import android.os.Build;
-import android.os.Bundle;
-import android.os.IBinder;
-import android.os.RemoteException;
-
-import org.chromium.base.Log;
-import org.chromium.base.TraceEvent;
-import org.chromium.base.VisibleForTesting;
-import org.chromium.base.process_launcher.ChildProcessCreationParams;
-import org.chromium.base.process_launcher.FileDescriptorInfo;
-import org.chromium.base.process_launcher.ICallbackInt;
-import org.chromium.base.process_launcher.IChildProcessService;
-
-import java.io.IOException;
-
-import javax.annotation.Nullable;
-
-/**
- * Manages a connection between the browser activity and a child service.
- */
-public class ChildProcessConnectionImpl implements ChildProcessConnection {
-    private final Context mContext;
-    private final int mServiceNumber;
-    private final boolean mInSandbox;
-    private final ChildProcessConnection.DeathCallback mDeathCallback;
-    private final ComponentName mServiceName;
-
-    // Synchronization: While most internal flow occurs on the UI thread, the public API
-    // (specifically start and stop) may be called from any thread, hence all entry point methods
-    // into the class are synchronized on the lock to protect access to these members.
-    private final Object mLock = new Object();
-    private IChildProcessService mService;
-    // Set to true when the service connection callback runs. This differs from
-    // mServiceConnectComplete, which tracks that the connection completed successfully.
-    private boolean mDidOnServiceConnected;
-    // Set to true when the service connected successfully.
-    private boolean mServiceConnectComplete;
-    // Set to true when the service disconnects, as opposed to being properly closed. This happens
-    // when the process crashes or gets killed by the system out-of-memory killer.
-    private boolean mServiceDisconnected;
-    // When the service disconnects (i.e. mServiceDisconnected is set to true), the status of the
-    // oom bindings is stashed here for future inspection.
-    private boolean mWasOomProtected;
-    private int mPid;  // Process ID of the corresponding child process.
-    // Initial binding protects the newly spawned process from being killed before it is put to use,
-    // it is maintained between calls to start() and removeInitialBinding().
-    private ChildServiceConnection mInitialBinding;
-    // Strong binding will make the service priority equal to the priority of the activity. We want
-    // the OS to be able to kill background renderers as it kills other background apps, so strong
-    // bindings are maintained only for services that are active at the moment (between
-    // addStrongBinding() and removeStrongBinding()).
-    private ChildServiceConnection mStrongBinding;
-    // Low priority binding maintained in the entire lifetime of the connection, i.e. between calls
-    // to start() and stop().
-    private ChildServiceConnection mWaivedBinding;
-    // Incremented on addStrongBinding(), decremented on removeStrongBinding().
-    private int mStrongBindingCount;
-    // Moderate binding will make the service priority equal to the priority of a visible process
-    // while the app is in the foreground. It will stay bound only while the app is in the
-    // foreground to protect a background process from the system out-of-memory killer.
-    private ChildServiceConnection mModerateBinding;
-
-    // Parameters passed to the child process through the service binding intent.
-    // If the service gets recreated by the framework the intent will be reused, so these parameters
-    // should be common to all processes of that type.
-    private final Bundle mChildProcessCommonParameters;
-
-    private final boolean mAlwaysInForeground;
-    private final ChildProcessCreationParams mCreationParams;
-
-    // Caches whether non-sandboxed and sandboxed services require an extra
-    // binding flag provided via ChildProcessCreationParams.
-    // TODO(mnaganov): Get rid of it after the release of the next Android SDK.
-    private static Boolean sNeedsExtrabindFlags[] = new Boolean[2];
-
-    private static final String TAG = "ChildProcessConnect";
-
-    private static class ConnectionParams {
-        final String[] mCommandLine;
-        final FileDescriptorInfo[] mFilesToBeMapped;
-        final IBinder mCallback;
-
-        ConnectionParams(
-                String[] commandLine, FileDescriptorInfo[] filesToBeMapped, IBinder callback) {
-            mCommandLine = commandLine;
-            mFilesToBeMapped = filesToBeMapped;
-            mCallback = callback;
-        }
-    }
-
-    // This is set in start() and is used in onServiceConnected().
-    private ChildProcessConnection.StartCallback mStartCallback;
-
-    // This is set in setupConnection() and is later used in doConnectionSetupLocked(), after which
-    // the variable is cleared. Therefore this is only valid while the connection is being set up.
-    private ConnectionParams mConnectionParams;
-
-    // Callback provided in setupConnection() that will communicate the result to the caller. This
-    // has to be called exactly once after setupConnection(), even if setup fails, so that the
-    // caller can free up resources associated with the setup attempt. This is set to null after the
-    // call.
-    private ChildProcessConnection.ConnectionCallback mConnectionCallback;
-
-    private class ChildServiceConnection implements ServiceConnection {
-        private boolean mBound;
-
-        private final int mBindFlags;
-
-        private Intent createServiceBindIntent() {
-            Intent intent = new Intent();
-            if (mCreationParams != null) {
-                mCreationParams.addIntentExtras(intent);
-            }
-            intent.setComponent(mServiceName);
-            return intent;
-        }
-
-        public ChildServiceConnection(int bindFlags) {
-            mBindFlags = bindFlags;
-        }
-
-        boolean bind() {
-            if (!mBound) {
-                try {
-                    TraceEvent.begin("ChildProcessConnectionImpl.ChildServiceConnection.bind");
-                    Intent intent = createServiceBindIntent();
-                    if (mChildProcessCommonParameters != null) {
-                        intent.putExtras(mChildProcessCommonParameters);
-                    }
-                    mBound = mContext.bindService(intent, this, mBindFlags);
-                } finally {
-                    TraceEvent.end("ChildProcessConnectionImpl.ChildServiceConnection.bind");
-                }
-            }
-            return mBound;
-        }
-
-        void unbind() {
-            if (mBound) {
-                mContext.unbindService(this);
-                mBound = false;
-            }
-        }
-
-        boolean isBound() {
-            return mBound;
-        }
-
-        @Override
-        public void onServiceConnected(ComponentName className, final IBinder service) {
-            LauncherThread.post(new Runnable() {
-                @Override
-                public void run() {
-                    ChildProcessConnectionImpl.this.onServiceConnectedOnLauncherThread(service);
-                }
-            });
-        }
-
-        // Called on the main thread to notify that the child service did not disconnect gracefully.
-        @Override
-        public void onServiceDisconnected(ComponentName className) {
-            LauncherThread.post(new Runnable() {
-                @Override
-                public void run() {
-                    ChildProcessConnectionImpl.this.onServiceDisconnectedOnLauncherThread();
-                }
-            });
-        }
-    }
-
-    ChildProcessConnectionImpl(Context context, int number, boolean inSandbox,
-            ChildProcessConnection.DeathCallback deathCallback, String serviceClassName,
-            Bundle childProcessCommonParameters, boolean alwaysInForeground,
-            ChildProcessCreationParams creationParams) {
-        mContext = context;
-        mServiceNumber = number;
-        mInSandbox = inSandbox;
-        mDeathCallback = deathCallback;
-        String packageName =
-                creationParams != null ? creationParams.getPackageName() : context.getPackageName();
-        mServiceName = new ComponentName(packageName, serviceClassName + mServiceNumber);
-        mChildProcessCommonParameters = childProcessCommonParameters;
-        mAlwaysInForeground = alwaysInForeground;
-        mCreationParams = creationParams;
-        int initialFlags = Context.BIND_AUTO_CREATE;
-        if (mAlwaysInForeground) initialFlags |= Context.BIND_IMPORTANT;
-        int extraBindFlags = 0;
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N && mCreationParams != null
-                && mCreationParams.getIsExternalService()
-                && isExportedService(inSandbox, mContext, mServiceName)) {
-            extraBindFlags = Context.BIND_EXTERNAL_SERVICE;
-        }
-        mInitialBinding = new ChildServiceConnection(initialFlags | extraBindFlags);
-        mStrongBinding = new ChildServiceConnection(
-                Context.BIND_AUTO_CREATE | Context.BIND_IMPORTANT | extraBindFlags);
-        mWaivedBinding = new ChildServiceConnection(
-                Context.BIND_AUTO_CREATE | Context.BIND_WAIVE_PRIORITY | extraBindFlags);
-        mModerateBinding = new ChildServiceConnection(Context.BIND_AUTO_CREATE | extraBindFlags);
-    }
-
-    private static boolean isExportedService(boolean inSandbox, Context context,
-            ComponentName serviceName) {
-        // Check for the cached value first. It is assumed that all pooled child services
-        // have identical attributes in the manifest.
-        final int arrayIndex = inSandbox ? 1 : 0;
-        if (sNeedsExtrabindFlags[arrayIndex] != null) {
-            return sNeedsExtrabindFlags[arrayIndex].booleanValue();
-        }
-        boolean result = false;
-        try {
-            PackageManager packageManager = context.getPackageManager();
-            ServiceInfo serviceInfo = packageManager.getServiceInfo(serviceName, 0);
-            result = serviceInfo.exported;
-        } catch (PackageManager.NameNotFoundException e) {
-            Log.e(TAG, "Could not retrieve info about service %s", serviceName, e);
-        }
-        sNeedsExtrabindFlags[arrayIndex] = Boolean.valueOf(result);
-        return result;
-    }
-
-    @Override
-    public int getServiceNumber() {
-        return mServiceNumber;
-    }
-
-    @Override
-    public boolean isInSandbox() {
-        return mInSandbox;
-    }
-
-    @Override
-    public String getPackageName() {
-        return mCreationParams != null ? mCreationParams.getPackageName()
-                : mContext.getPackageName();
-    }
-
-    @Override
-    public ChildProcessCreationParams getCreationParams() {
-        return mCreationParams;
-    }
-
-    @Override
-    public IChildProcessService getService() {
-        synchronized (mLock) {
-            return mService;
-        }
-    }
-
-    @Override
-    public int getPid() {
-        synchronized (mLock) {
-            return mPid;
-        }
-    }
-
-    @Override
-    public void start(ChildProcessConnection.StartCallback startCallback) {
-        try {
-            TraceEvent.begin("ChildProcessConnectionImpl.start");
-            assert LauncherThread.runningOnLauncherThread();
-            synchronized (mLock) {
-                assert mConnectionParams == null :
-                        "setupConnection() called before start() in ChildProcessConnectionImpl.";
-
-                mStartCallback = startCallback;
-
-                if (!mInitialBinding.bind()) {
-                    Log.e(TAG, "Failed to establish the service connection.");
-                    // We have to notify the caller so that they can free-up associated resources.
-                    // TODO(ppi): Can we hard-fail here?
-                    mDeathCallback.onChildProcessDied(ChildProcessConnectionImpl.this);
-                } else {
-                    mWaivedBinding.bind();
-                }
-            }
-        } finally {
-            TraceEvent.end("ChildProcessConnectionImpl.start");
-        }
-    }
-
-    @Override
-    public void setupConnection(String[] commandLine, FileDescriptorInfo[] filesToBeMapped,
-            @Nullable IBinder callback, ConnectionCallback connectionCallback) {
-        assert LauncherThread.runningOnLauncherThread();
-        synchronized (mLock) {
-            assert mConnectionParams == null;
-            if (mServiceDisconnected) {
-                Log.w(TAG, "Tried to setup a connection that already disconnected.");
-                connectionCallback.onConnected(0);
-                return;
-            }
-            try {
-                TraceEvent.begin("ChildProcessConnectionImpl.setupConnection");
-                mConnectionCallback = connectionCallback;
-                mConnectionParams = new ConnectionParams(commandLine, filesToBeMapped, callback);
-                // Run the setup if the service is already connected. If not,
-                // doConnectionSetupLocked() will be called from onServiceConnected().
-                if (mServiceConnectComplete) {
-                    doConnectionSetupLocked();
-                }
-            } finally {
-                TraceEvent.end("ChildProcessConnectionImpl.setupConnection");
-            }
-        }
-    }
-
-    @Override
-    public void stop() {
-        synchronized (mLock) {
-            mInitialBinding.unbind();
-            mStrongBinding.unbind();
-            mWaivedBinding.unbind();
-            mModerateBinding.unbind();
-            mStrongBindingCount = 0;
-            if (mService != null) {
-                mService = null;
-            }
-            mConnectionParams = null;
-        }
-    }
-
-    private void onServiceConnectedOnLauncherThread(IBinder service) {
-        assert LauncherThread.runningOnLauncherThread();
-        synchronized (mLock) {
-            // A flag from the parent class ensures we run the post-connection logic only once
-            // (instead of once per each ChildServiceConnection).
-            if (mDidOnServiceConnected) {
-                return;
-            }
-            try {
-                TraceEvent.begin(
-                        "ChildProcessConnectionImpl.ChildServiceConnection.onServiceConnected");
-                mDidOnServiceConnected = true;
-                mService = IChildProcessService.Stub.asInterface(service);
-
-                StartCallback startCallback = mStartCallback;
-                mStartCallback = null;
-
-                final boolean bindCheck =
-                        mCreationParams != null && mCreationParams.getBindToCallerCheck();
-                boolean boundToUs = false;
-                try {
-                    boundToUs = bindCheck ? mService.bindToCaller() : true;
-                } catch (RemoteException ex) {
-                    // Do not trigger the StartCallback here, since the service is already
-                    // dead and the DeathCallback will run from onServiceDisconnected().
-                    Log.e(TAG, "Failed to bind service to connection.", ex);
-                    return;
-                }
-
-                if (startCallback != null) {
-                    if (boundToUs) {
-                        startCallback.onChildStarted();
-                    } else {
-                        startCallback.onChildStartFailed();
-                    }
-                }
-
-                if (!boundToUs) {
-                    return;
-                }
-
-                mServiceConnectComplete = true;
-
-                // Run the setup if the connection parameters have already been provided. If
-                // not, doConnectionSetupLocked() will be called from setupConnection().
-                if (mConnectionParams != null) {
-                    doConnectionSetupLocked();
-                }
-            } finally {
-                TraceEvent.end(
-                        "ChildProcessConnectionImpl.ChildServiceConnection.onServiceConnected");
-            }
-        }
-    }
-
-    private void onServiceDisconnectedOnLauncherThread() {
-        assert LauncherThread.runningOnLauncherThread();
-        synchronized (mLock) {
-            // Ensure that the disconnection logic runs only once (instead of once per each
-            // ChildServiceConnection).
-            if (mServiceDisconnected) {
-                return;
-            }
-            // Stash the status of the oom bindings, since stop() will release all bindings.
-            mWasOomProtected = isCurrentlyOomProtected();
-            mServiceDisconnected = true;
-            Log.w(TAG, "onServiceDisconnected (crash or killed by oom): pid=%d", mPid);
-            stop(); // We don't want to auto-restart on crash. Let the browser do that.
-            mDeathCallback.onChildProcessDied(ChildProcessConnectionImpl.this);
-            // If we have a pending connection callback, we need to communicate the failure to
-            // the caller.
-            if (mConnectionCallback != null) {
-                mConnectionCallback.onConnected(0);
-            }
-            mConnectionCallback = null;
-        }
-    }
-
-    private void onSetupConnectionResult(int pid) {
-        synchronized (mLock) {
-            mPid = pid;
-            assert mPid != 0 : "Child service claims to be run by a process of pid=0.";
-
-            if (mConnectionCallback != null) {
-                mConnectionCallback.onConnected(mPid);
-            }
-            mConnectionCallback = null;
-        }
-    }
-
-    /**
-     * Called after the connection parameters have been set (in setupConnection()) *and* a
-     * connection has been established (as signaled by onServiceConnected()). These two events can
-     * happen in any order. Has to be called with mLock.
-     */
-    private void doConnectionSetupLocked() {
-        try {
-            TraceEvent.begin("ChildProcessConnectionImpl.doConnectionSetupLocked");
-            assert mServiceConnectComplete && mService != null;
-            assert mConnectionParams != null;
-
-            Bundle bundle = ChildProcessLauncher.createsServiceBundle(
-                    mConnectionParams.mCommandLine, mConnectionParams.mFilesToBeMapped);
-            ICallbackInt pidCallback = new ICallbackInt.Stub() {
-                @Override
-                public void call(final int pid) {
-                    LauncherThread.post(new Runnable() {
-                        @Override
-                        public void run() {
-                            onSetupConnectionResult(pid);
-                        }
-                    });
-                }
-            };
-            try {
-                mService.setupConnection(bundle, pidCallback, mConnectionParams.mCallback);
-            } catch (RemoteException re) {
-                Log.e(TAG, "Failed to setup connection.", re);
-            }
-            // We proactively close the FDs rather than wait for GC & finalizer.
-            try {
-                for (FileDescriptorInfo fileInfo : mConnectionParams.mFilesToBeMapped) {
-                    fileInfo.fd.close();
-                }
-            } catch (IOException ioe) {
-                Log.w(TAG, "Failed to close FD.", ioe);
-            }
-            mConnectionParams = null;
-        } finally {
-            TraceEvent.end("ChildProcessConnectionImpl.doConnectionSetupLocked");
-        }
-    }
-
-    @Override
-    public boolean isInitialBindingBound() {
-        synchronized (mLock) {
-            return mInitialBinding.isBound();
-        }
-    }
-
-    @Override
-    public boolean isStrongBindingBound() {
-        synchronized (mLock) {
-            return mStrongBinding.isBound();
-        }
-    }
-
-    @Override
-    public void removeInitialBinding() {
-        synchronized (mLock) {
-            assert !mAlwaysInForeground;
-            mInitialBinding.unbind();
-        }
-    }
-
-    @Override
-    public boolean isOomProtectedOrWasWhenDied() {
-        synchronized (mLock) {
-            if (mServiceDisconnected) {
-                return mWasOomProtected;
-            } else {
-                return isCurrentlyOomProtected();
-            }
-        }
-    }
-
-    private boolean isCurrentlyOomProtected() {
-        synchronized (mLock) {
-            assert !mServiceDisconnected;
-            if (mAlwaysInForeground) return ChildProcessLauncher.isApplicationInForeground();
-            return mInitialBinding.isBound() || mStrongBinding.isBound();
-        }
-    }
-
-    @Override
-    public void dropOomBindings() {
-        synchronized (mLock) {
-            assert !mAlwaysInForeground;
-            mInitialBinding.unbind();
-
-            mStrongBindingCount = 0;
-            mStrongBinding.unbind();
-
-            mModerateBinding.unbind();
-        }
-    }
-
-    @Override
-    public void addStrongBinding() {
-        synchronized (mLock) {
-            if (mService == null) {
-                Log.w(TAG, "The connection is not bound for %d", mPid);
-                return;
-            }
-            if (mStrongBindingCount == 0) {
-                mStrongBinding.bind();
-            }
-            mStrongBindingCount++;
-        }
-    }
-
-    @Override
-    public void removeStrongBinding() {
-        synchronized (mLock) {
-            if (mService == null) {
-                Log.w(TAG, "The connection is not bound for %d", mPid);
-                return;
-            }
-            assert mStrongBindingCount > 0;
-            mStrongBindingCount--;
-            if (mStrongBindingCount == 0) {
-                mStrongBinding.unbind();
-            }
-        }
-    }
-
-    @Override
-    public boolean isModerateBindingBound() {
-        synchronized (mLock) {
-            return mModerateBinding.isBound();
-        }
-    }
-
-    @Override
-    public void addModerateBinding() {
-        synchronized (mLock) {
-            if (mService == null) {
-                Log.w(TAG, "The connection is not bound for %d", mPid);
-                return;
-            }
-            mModerateBinding.bind();
-        }
-    }
-
-    @Override
-    public void removeModerateBinding() {
-        synchronized (mLock) {
-            if (mService == null) {
-                Log.w(TAG, "The connection is not bound for %d", mPid);
-                return;
-            }
-            mModerateBinding.unbind();
-        }
-    }
-
-    @VisibleForTesting
-    public void crashServiceForTesting() throws RemoteException {
-        mService.crashIntentionallyForTesting();
-    }
-
-    @VisibleForTesting
-    public boolean isConnected() {
-        return mService != null;
-    }
-}