Implement SmartText selection.

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

+// Copyright 2017 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.support.annotation.IntDef;
+import android.text.TextUtils;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.content_public.browser.WebContents;
+import org.chromium.ui.base.WindowAndroid;
+import org.chromium.ui.touch_selection.SelectionEventType;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * A class that controls the classification of the textual selection.
+ * It requests the selection together with its surrounding text from
+ * the focused frame and sends it to ContextSelectionProvider
+ * which does the classification itself.
+ */
+@JNINamespace("content")
+public class ContextSelectionClient implements SelectionClient {
+    private static final String TAG = "ContextSelClient"; // 20 char limit

[boliu, 2017/03/20 20:27:26]

not used

[Tima Vaisburd, 2017/03/21 02:07:02]

Removed.

+
+    @IntDef({CLASSIFY, SUGGEST_AND_CLASSIFY})
+    @Retention(RetentionPolicy.SOURCE)
+    private @interface RequestType {}
+
+    private static final int CLASSIFY = 0;
+    private static final int SUGGEST_AND_CLASSIFY = 1;
+
+    // The callback that would receive the information from ContextSelectionProvider.
+    private class ProviderCallback implements ContextSelectionProvider.ResultCallback {
+        @Override
+        public void onClassified(ContextSelectionProvider.Result result) {
+            mOuterCallback.onClassified(result);
+        }
+    };
+
+    private long mNativeContextSelectionClient;
+    private ContextSelectionProvider mProvider;
+    private ProviderCallback mProviderCallback;
+    private ContextSelectionProvider.ResultCallback mOuterCallback;
+
+    /**
+     * Creates the ContextSelectionClient. Returns null in case ContextSelectionProvider
+     * does not exist in the system.
+     */
+    public static ContextSelectionClient create(ContextSelectionProvider.ResultCallback callback,
+            WindowAndroid windowAndroid, WebContents webContent) {
+        ContextSelectionClient client = new ContextSelectionClient(callback);
+        if (!client.initialize(windowAndroid, webContent)) client = null;
+        return client;
+    }
+
+    private ContextSelectionClient(ContextSelectionProvider.ResultCallback callback) {
+        mOuterCallback = callback;
+    }
+
+    private boolean initialize(WindowAndroid windowAndroid, WebContents webContents) {
+        // We make a chain of callbacks: this class receiive result from provider through
+        // mProviderCallback and passes the info to embedder with mOuterCallback.
+        mProviderCallback = new ProviderCallback();
+        mProvider = ContentClassFactory.get().createContextSelectionProvider(
+                mProviderCallback, windowAndroid);
+
+        // ContextSelectionProvider might not exist.
+        if (mProvider == null) {
+            return false;
+        }
+
+        mNativeContextSelectionClient = nativeInit(webContents);
+        return true;
+    }
+
+    @CalledByNative
+    private void onNativeSideDestroyed(long nativeContextSelectionClient) {
+        assert nativeContextSelectionClient == mNativeContextSelectionClient;
+        mNativeContextSelectionClient = 0;
+    }
+
+    // SelectionClient implementation
+    @Override
+    public void onSelectionChanged(String selection) {}
+
+    @Override
+    public void onSelectionEvent(int eventType, float posXPix, float posYPix) {
+        switch (eventType) {
+            case SelectionEventType.SELECTION_HANDLES_SHOWN:
+                // This event is sent when the long press is detected which causes
+                // selection to appear for the first time. Temporarily hiding the
+                // handles that happens e.g. during scroll does not affect this event.
+                requestSurroundingText(SUGGEST_AND_CLASSIFY);
+                break;
+
+            case SelectionEventType.SELECTION_HANDLES_CLEARED:
+                // The ActionMode should be stopped when this event comes.
+                cancelAllRequests();
+                break;
+
+            case SelectionEventType.SELECTION_HANDLE_DRAG_STOPPED:
+                // This event is sent after a user stopped dragging one of the
+                // selection handles, i.e. stopped modifying the selection.
+                requestSurroundingText(CLASSIFY);
+                break;
+
+            default:
+                break; // ignore
+        }
+    }
+
+    @Override
+    public void showUnhandledTapUIIfNeeded(int x, int y) {}
+
+    @Override
+    public boolean sendsMenuUpdates() {
+        return true;
+    }
+
+    private void cancelAllRequests() {
+        if (mNativeContextSelectionClient != 0) {
+            nativeCancelAllRequests(mNativeContextSelectionClient);
+        }
+
+        mProvider.cancelAllRequests();
+    }
+
+    private void requestSurroundingText(@RequestType int callbackData) {
+        if (mNativeContextSelectionClient == 0) {
+            onSurroundingTextReceived(callbackData, "", 0, 0);
+            return;
+        }
+
+        nativeRequestSurroundingText(mNativeContextSelectionClient, callbackData);
+    }
+
+    @CalledByNative
+    private void onSurroundingTextReceived(
+            @RequestType int callbackData, String text, int start, int end) {
+        if (TextUtils.isEmpty(text)) {
+            mOuterCallback.onClassified(new ContextSelectionProvider.Result());
+            return;
+        }
+
+        switch (callbackData) {
+            case SUGGEST_AND_CLASSIFY:
+                mProvider.sendSuggestAndClassifyRequest(text, start, end);
+                break;
+
+            case CLASSIFY:
+                mProvider.sendClassifyRequest(text, start, end);
+                break;
+
+            default:
+                assert false : "Unexpected callback data";
+                break;
+        }
+    }
+
+    private native long nativeInit(WebContents webContents);
+    private native void nativeRequestSurroundingText(
+            long nativeContextSelectionClient, int callbackData);
+    private native void nativeCancelAllRequests(long nativeContextSelectionClient);
+}