Move Range out of RichInputConnection and rename it.

Range has grown a bit too big to stay an internal class.

Change-Id: Ic3fbc48a5d10776eedd7559c4d696e5926b88288

1 files changed, 116 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/utils/TextRange.java b/java/src/com/android/inputmethod/latin/utils/TextRange.java
new file mode 100644
index 000000000..5793e4170
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/utils/TextRange.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.latin.utils;
+
+import android.text.Spanned;
+import android.text.style.SuggestionSpan;
+
+import java.util.Arrays;
+
+/**
+ * Represents a range of text, relative to the current cursor position.
+ */
+public final class TextRange {
+    private final CharSequence mTextAtCursor;
+    private final int mWordAtCursorStartIndex;
+    private final int mWordAtCursorEndIndex;
+    private final int mCursorIndex;
+
+    public final CharSequence mWord;
+
+    public int getNumberOfCharsInWordBeforeCursor() {
+        return mCursorIndex - mWordAtCursorStartIndex;
+    }
+
+    public int getNumberOfCharsInWordAfterCursor() {
+        return mWordAtCursorEndIndex - mCursorIndex;
+    }
+
+    /**
+     * Gets the suggestion spans that are put squarely on the word, with the exact start
+     * and end of the span matching the boundaries of the word.
+     * @return the list of spans.
+     */
+    public SuggestionSpan[] getSuggestionSpansAtWord() {
+        if (!(mTextAtCursor instanceof Spanned && mWord instanceof Spanned)) {
+            return new SuggestionSpan[0];
+        }
+        final Spanned text = (Spanned)mTextAtCursor;
+        // Note: it's fine to pass indices negative or greater than the length of the string
+        // to the #getSpans() method. The reason we need to get from -1 to +1 is that, the
+        // spans were cut at the cursor position, and #getSpans(start, end) does not return
+        // spans that end at `start' or begin at `end'. Consider the following case:
+        //              this| is          (The | symbolizes the cursor position
+        //              ---- ---
+        // In this case, the cursor is in position 4, so the 0~7 span has been split into
+        // a 0~4 part and a 4~7 part.
+        // If we called #getSpans(0, 4) in this case, we would only get the part from 0 to 4
+        // of the span, and not the part from 4 to 7, so we would not realize the span actually
+        // extends from 0 to 7. But if we call #getSpans(-1, 5) we'll get both the 0~4 and
+        // the 4~7 spans and we can merge them accordingly.
+        // Any span starting more than 1 char away from the word boundaries in any direction
+        // does not touch the word, so we don't need to consider it. That's why requesting
+        // -1 ~ +1 is enough.
+        // Of course this is only relevant if the cursor is at one end of the word. If it's
+        // in the middle, the -1 and +1 are not necessary, but they are harmless.
+        final SuggestionSpan[] spans = text.getSpans(mWordAtCursorStartIndex - 1,
+                mWordAtCursorEndIndex + 1, SuggestionSpan.class);
+        int readIndex = 0;
+        int writeIndex = 0;
+        for (; readIndex < spans.length; ++readIndex) {
+            final SuggestionSpan span = spans[readIndex];
+            // The span may be null, as we null them when we find duplicates. Cf a few lines
+            // down.
+            if (null == span) continue;
+            // Tentative span start and end. This may be modified later if we realize the
+            // same span is also applied to other parts of the string.
+            int spanStart = text.getSpanStart(span);
+            int spanEnd = text.getSpanEnd(span);
+            for (int i = readIndex + 1; i < spans.length; ++i) {
+                if (span.equals(spans[i])) {
+                    // We found the same span somewhere else. Read the new extent of this
+                    // span, and adjust our values accordingly.
+                    spanStart = Math.min(spanStart, text.getSpanStart(spans[i]));
+                    spanEnd = Math.max(spanEnd, text.getSpanEnd(spans[i]));
+                    // ...and mark the span as processed.
+                    spans[i] = null;
+                }
+            }
+            if (spanStart == mWordAtCursorStartIndex && spanEnd == mWordAtCursorEndIndex) {
+                // If the span does not start and stop here, we ignore it. It probably extends
+                // past the start or end of the word, as happens in missing space correction
+                // or EasyEditSpans put by voice input.
+                spans[writeIndex++] = spans[readIndex];
+            }
+        }
+        return writeIndex == readIndex ? spans : Arrays.copyOfRange(spans, 0, writeIndex);
+    }
+
+    public TextRange(final CharSequence textAtCursor, final int wordAtCursorStartIndex,
+            final int wordAtCursorEndIndex, final int cursorIndex) {
+        if (wordAtCursorStartIndex < 0 || cursorIndex < wordAtCursorStartIndex
+                || cursorIndex > wordAtCursorEndIndex
+                || wordAtCursorEndIndex > textAtCursor.length()) {
+            throw new IndexOutOfBoundsException();
+        }
+        mTextAtCursor = textAtCursor;
+        mWordAtCursorStartIndex = wordAtCursorStartIndex;
+        mWordAtCursorEndIndex = wordAtCursorEndIndex;
+        mCursorIndex = cursorIndex;
+        mWord = mTextAtCursor.subSequence(mWordAtCursorStartIndex, mWordAtCursorEndIndex);
+    }
+}
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