Implemented typo recognition in Chrome for Android.

chrome/android/java/src/org/chromium/chrome/browser/spellchecker/SpellCheckerSessionBridge.java

Index: chrome/android/java/src/org/chromium/chrome/browser/spellchecker/SpellCheckerSessionBridge.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/spellchecker/SpellCheckerSessionBridge.java b/chrome/android/java/src/org/chromium/chrome/browser/spellchecker/SpellCheckerSessionBridge.java
new file mode 100644
index 0000000000000000000000000000000000000000..6ff206657646b317227bcd8dd75ebd34e6b71d24
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/spellchecker/SpellCheckerSessionBridge.java
@@ -0,0 +1,110 @@
+// Copyright 2015 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.chrome.browser.spellchecker;
+
+import android.content.Context;
+import android.view.textservice.SentenceSuggestionsInfo;
+import android.view.textservice.SpellCheckerSession;
+import android.view.textservice.SuggestionsInfo;
+import android.view.textservice.TextInfo;
+import android.view.textservice.TextServicesManager;
+
+import org.chromium.base.ApplicationStatus;
+import org.chromium.base.annotations.CalledByNative;
+
+import java.util.ArrayList;
+import java.util.Locale;
+
+/**
+* JNI interface for spellcheck_platform_android to use Android's spellchecker.
+*/
+public class SpellCheckerSessionBridge implements SpellCheckerSession.SpellCheckerSessionListener {
+    private boolean mIsActiveRequest;
+    private boolean mIsPendingRequest;
+    private SpellCheckerSession mSpellCheckerSession;
+    private final long mNativeSpellCheckerSessionBridge;
+    private String mActiveText;
+    private String mPendingText;
+
+    public SpellCheckerSessionBridge(long nativeSpellCheckerSessionBridge) {
+        mNativeSpellCheckerSessionBridge = nativeSpellCheckerSessionBridge;
+        Context context = ApplicationStatus.getApplicationContext();
+        final TextServicesManager textServicesManager =
+                (TextServicesManager) context.getSystemService(
+                        Context.TEXT_SERVICES_MANAGER_SERVICE);
+        mSpellCheckerSession =
+                textServicesManager.newSpellCheckerSession(null, Locale.ENGLISH, this, true);
+    }
+
+    @CalledByNative
+    private static SpellCheckerSessionBridge create(long nativeSpellCheckerSessionBridge) {
+        return new SpellCheckerSessionBridge(nativeSpellCheckerSessionBridge);
+    }
+
+    @CalledByNative
+    private void checkSpelling(String text) {
+        // The listener can't handle multiple events in rapid sequence
+        // Save incoming request text to run at the end of the currently active request
+        // If multiple requests arrive during one active request, only the most
+        // recent request will run (the others get overwritten).
+        if (mIsActiveRequest) {
+            System.out.println("DYLANKING Setting Pending Text To: " + text);

[please use gerrit instead, 2015/08/11 16:43:46]

Remove the log.

[dylanking, 2015/08/12 00:16:26]

Don't know how that snuck through. Deleted.

+            mIsPendingRequest = true;
+            mPendingText = text;
+            return;
+        }
+        mIsActiveRequest = true;
+        mActiveText = text;
+        mSpellCheckerSession.getSentenceSuggestions(new TextInfo[] {new TextInfo(mActiveText)}, 5);

[please use gerrit instead, 2015/08/11 16:43:46]

What is 5?

[dylanking, 2015/08/12 00:16:26]

The second parameter to this function is the maximum number of suggestions per
word that we want returned to us by the spellchecker when we send off the text
for spellchecking.  I picked 5 because that's the default number that the
Android spellchecker seems to use.

However, since we are not currently displaying or doing anything with these
suggestions, I suppose I can change this to 0 for now.

+    }
+
+    @Override
+    public void onGetSentenceSuggestions(SentenceSuggestionsInfo[] results) {
+        ArrayList<Integer> offsets = new ArrayList<Integer>();
+        ArrayList<Integer> lengths = new ArrayList<Integer>();
+
+        for (SentenceSuggestionsInfo result : results) {
+            for (int i = 0; i < result.getSuggestionsCount(); i++) {
+                SuggestionsInfo currentSuggestion = result.getSuggestionsInfoAt(i);
+                boolean isWordCorrect = (currentSuggestion.getSuggestionsAttributes()
+                                                & SuggestionsInfo.RESULT_ATTR_LOOKS_LIKE_TYPO)
+                        == 0;
+                if (!isWordCorrect) {
+                    offsets.add(result.getOffsetAt(i));
+                    lengths.add(result.getLengthAt(i));
+                }
+            }
+        }
+
+        nativeGetSpellcheckInfo(mNativeSpellCheckerSessionBridge, mActiveText,
+                convertListToArray(offsets), convertListToArray(lengths));
+
+        // If any requests arrived during the execution of this request, run the
+        // most recent request.
+        if (mIsPendingRequest) {
+            mIsPendingRequest = false;

[please use gerrit instead, 2015/08/11 16:43:46]

You're saving pending text here, but identifier and route_id are overwritten in
C++. You should save all of that information in one place. I suggest that you
keep all request-specific information together. You need to keep track of two
requests: the current one and the pending one.

[dylanking, 2015/08/12 00:16:26]

Great point.  I've created an inner class to encapsulate this information and
keep it in one place.

+            mActiveText = mPendingText;
+            mSpellCheckerSession.getSentenceSuggestions(
+                    new TextInfo[] {new TextInfo(mActiveText)}, 5);
+        } else {
+            mIsActiveRequest = false;
+        }
+    }
+
+    private int[] convertListToArray(ArrayList<Integer> toConvert) {

[please use gerrit instead, 2015/08/11 16:43:46]

Do any of these work?

https://docs.oracle.com/javase/8/docs/api/java/util/ArrayList.html#toArray--
https://docs.oracle.com/javase/8/docs/api/java/util/ArrayList.html#toArray-T:A-

[dylanking, 2015/08/12 00:16:26]

I think those will convert the list of Integer *objects* into an array of
Integer objects, whereas I wanted an array of *primitive* ints to send back to
native, as they are easier to use when it comes to passing the array to native.

However, if you think it may be a performance gain to use one of the linked
methods and send back a jobjectArray (and then work some JNI magic to extract
each object's int value), instead of a jintArray, I can do that.

+        int[] toReturn = new int[toConvert.size()];
+        int index = 0;
+        for (Integer number : toConvert) {
+            toReturn[index++] = number.intValue();
+        }
+        return toReturn;
+    }
+
+    @Override
+    public void onGetSuggestions(SuggestionsInfo[] results) {}
+
+    private native void nativeGetSpellcheckInfo(
+            long nativeSpellCheckerSessionBridge, String text, int[] offsets, int[] lengths);
+}