Ensure each character is coverted by at most one LocaleSpan

This is a groundwork to attach LocaleSpan for committed text
in LatinIME.

This CL adds a utility method to ensure that a given range
of the text is coverted by at most one LocaleSpan.  Of course
it could be possible to allow a substring to be coverted by
multiple LocaleSpans at the same time, but ensuring uniqueness
for LocaleSpan is supposed to be a good starting point.

BUG: 16029304
Change-Id: Ic33a7178d0df1f05d3626aeb5773ec902254703f

1 files changed, 174 insertions, 0 deletions

diff --git a/tests/src/com/android/inputmethod/compat/LocaleSpanCompatUtilsTests.java b/tests/src/com/android/inputmethod/compat/LocaleSpanCompatUtilsTests.java
index a920373d4..319302c71 100644
--- a/tests/src/com/android/inputmethod/compat/LocaleSpanCompatUtilsTests.java
+++ b/tests/src/com/android/inputmethod/compat/LocaleSpanCompatUtilsTests.java
@@ -16,9 +16,14 @@
 
 package com.android.inputmethod.compat;
 
+import android.graphics.Typeface;
 import android.os.Build;
 import android.test.AndroidTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
+import android.text.Spannable;
+import android.text.SpannableString;
+import android.text.Spanned;
+import android.text.style.StyleSpan;
 
 import java.util.Locale;
 
@@ -35,4 +40,173 @@ public class LocaleSpanCompatUtilsTests extends AndroidTestCase {
         assertEquals(Locale.JAPANESE,
                 LocaleSpanCompatUtils.getLocaleFromLocaleSpan(japaneseLocaleSpan));
     }
+
+    private static void assertLocaleSpan(final Spanned spanned, final int index,
+            final int expectedStart, final int expectedEnd,
+            final Locale expectedLocale, final int expectedSpanFlags) {
+        final Object span = spanned.getSpans(0, spanned.length(), Object.class)[index];
+        assertEquals(expectedLocale, LocaleSpanCompatUtils.getLocaleFromLocaleSpan(span));
+        assertEquals(expectedStart, spanned.getSpanStart(span));
+        assertEquals(expectedEnd, spanned.getSpanEnd(span));
+        assertEquals(expectedSpanFlags, spanned.getSpanFlags(span));
+    }
+
+    private static void assertSpanEquals(final Object expectedSpan, final Spanned spanned,
+            final int index) {
+        final Object[] spans = spanned.getSpans(0, spanned.length(), Object.class);
+        assertEquals(expectedSpan, spans[index]);
+    }
+
+    private static void assertSpanCount(final int expectedCount, final Spanned spanned) {
+        final Object[] spans = spanned.getSpans(0, spanned.length(), Object.class);
+        assertEquals(expectedCount, spans.length);
+    }
+
+    public void testUpdateLocaleSpan() {
+        if (!LocaleSpanCompatUtils.isLocaleSpanAvailable()) {
+            return;
+        }
+
+        // Test if the simplest case works.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 1, 5, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 5, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if only LocaleSpans are updated.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            final StyleSpan styleSpan = new StyleSpan(Typeface.BOLD);
+            text.setSpan(styleSpan, 0, 7, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 1, 5, Locale.JAPANESE);
+            assertSpanCount(2, text);
+            assertSpanEquals(styleSpan, text, 0);
+            assertLocaleSpan(text, 1, 1, 5, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if two jointed spans are merged into one span.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 1, 3,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 3, 5, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 5, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if two overlapped spans are merged into one span.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 1, 4,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 3, 5, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 5, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if three overlapped spans are merged into one span.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 1, 4,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 5, 6,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 2, 8, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 8, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if disjoint spans remain disjoint.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 1, 3,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 5, 6,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 8, 9, Locale.JAPANESE);
+            assertSpanCount(3, text);
+            assertLocaleSpan(text, 0, 1, 3, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            assertLocaleSpan(text, 1, 5, 6, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            assertLocaleSpan(text, 2, 8, 9, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if existing span flags are preserved during merge.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 1, 5,
+                    Spannable.SPAN_INCLUSIVE_INCLUSIVE | Spannable.SPAN_INTERMEDIATE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 3, 4, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 5, Locale.JAPANESE,
+                    Spannable.SPAN_INCLUSIVE_INCLUSIVE | Spannable.SPAN_INTERMEDIATE);
+        }
+
+        // Test if existing span flags are preserved even when partially overlapped (leading edge).
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 1, 5,
+                    Spannable.SPAN_INCLUSIVE_INCLUSIVE | Spannable.SPAN_INTERMEDIATE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 3, 7, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 7, Locale.JAPANESE,
+                    Spannable.SPAN_INCLUSIVE_EXCLUSIVE | Spannable.SPAN_INTERMEDIATE);
+        }
+
+        // Test if existing span flags are preserved even when partially overlapped (trailing edge).
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.JAPANESE), 3, 7,
+                    Spannable.SPAN_INCLUSIVE_INCLUSIVE | Spannable.SPAN_INTERMEDIATE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 1, 5, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 7, Locale.JAPANESE,
+                    Spannable.SPAN_EXCLUSIVE_INCLUSIVE | Spannable.SPAN_INTERMEDIATE);
+        }
+
+        // Test if existing locale span will be removed when the locale doesn't match.
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.ENGLISH), 3, 5,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 1, 7, Locale.JAPANESE);
+            assertSpanCount(1, text);
+            assertLocaleSpan(text, 0, 1, 7, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if existing locale span will be removed when the locale doesn't match. (case 2)
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.ENGLISH), 3, 7,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 5, 6, Locale.JAPANESE);
+            assertSpanCount(3, text);
+            assertLocaleSpan(text, 0, 3, 5, Locale.ENGLISH, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            assertLocaleSpan(text, 1, 6, 7, Locale.ENGLISH, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            assertLocaleSpan(text, 2, 5, 6, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if existing locale span will be removed when the locale doesn't match. (case 3)
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.ENGLISH), 3, 7,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 2, 5, Locale.JAPANESE);
+            assertSpanCount(2, text);
+            assertLocaleSpan(text, 0, 5, 7, Locale.ENGLISH, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            assertLocaleSpan(text, 1, 2, 5, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+
+        // Test if existing locale span will be removed when the locale doesn't match. (case 3)
+        {
+            final SpannableString text = new SpannableString("0123456789");
+            text.setSpan(LocaleSpanCompatUtils.newLocaleSpan(Locale.ENGLISH), 3, 7,
+                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            LocaleSpanCompatUtils.updateLocaleSpan(text, 5, 8, Locale.JAPANESE);
+            assertSpanCount(2, text);
+            assertLocaleSpan(text, 0, 3, 5, Locale.ENGLISH, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            assertLocaleSpan(text, 1, 5, 8, Locale.JAPANESE, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+        }
+    }
 }