Adds support for a fall-back model when the language-specific model is not found.

Bug: 74720318

Test: Builds and fall-back works.
Test: bit FrameworksCoreTests:android.view.textclassifier.TextClassificationManagerTest
Test: bit CtsViewTestCases:android.view.textclassifier.cts.TextClassificationManagerTest
Change-Id: I5491af628c8406e42ca2cc971ad3a8b708ceb315

1 files changed, 28 insertions, 6 deletions

diff --git a/core/java/android/view/textclassifier/TextClassifierImpl.java b/core/java/android/view/textclassifier/TextClassifierImpl.java
index a09982053091..89e6262257c5 100644
--- a/core/java/android/view/textclassifier/TextClassifierImpl.java
+++ b/core/java/android/view/textclassifier/TextClassifierImpl.java
@@ -355,12 +355,10 @@ public final class TextClassifierImpl implements TextClassifier {
         final List<Locale.LanguageRange> languageRangeList = Locale.LanguageRange.parse(languages);
 
         ModelFile bestModel = null;
-        int bestModelVersion = -1;
         for (ModelFile model : listAllModelsLocked()) {
             if (model.isAnyLanguageSupported(languageRangeList)) {
-                if (model.getVersion() >= bestModelVersion) {
+                if (model.isPreferredTo(bestModel)) {
                     bestModel = model;
-                    bestModelVersion = model.getVersion();
                 }
             }
         }
@@ -482,6 +480,7 @@ public final class TextClassifierImpl implements TextClassifier {
         private final String mName;
         private final int mVersion;
         private final List<Locale> mSupportedLocales;
+        private final boolean mLanguageIndependent;
 
         /** Returns null if the path did not point to a compatible model. */
         static @Nullable ModelFile fromPath(String path) {
@@ -496,12 +495,14 @@ public final class TextClassifierImpl implements TextClassifier {
                     Log.d(DEFAULT_LOG_TAG, "Ignoring " + file.getAbsolutePath());
                     return null;
                 }
+                final boolean languageIndependent = supportedLocalesStr.equals("*");
                 final List<Locale> supportedLocales = new ArrayList<>();
                 for (String langTag : supportedLocalesStr.split(",")) {
                     supportedLocales.add(Locale.forLanguageTag(langTag));
                 }
                 closeAndLogError(modelFd);
-                return new ModelFile(path, file.getName(), version, supportedLocales);
+                return new ModelFile(path, file.getName(), version, supportedLocales,
+                                     languageIndependent);
             } catch (FileNotFoundException e) {
                 Log.e(DEFAULT_LOG_TAG, "Failed to peek " + file.getAbsolutePath(), e);
                 return null;
@@ -525,7 +526,7 @@ public final class TextClassifierImpl implements TextClassifier {
 
         /** Returns whether the language supports any language in the given ranges. */
         boolean isAnyLanguageSupported(List<Locale.LanguageRange> languageRanges) {
-            return Locale.lookup(languageRanges, mSupportedLocales) != null;
+            return mLanguageIndependent || Locale.lookup(languageRanges, mSupportedLocales) != null;
         }
 
         /** All locales supported by the model. */
@@ -533,6 +534,25 @@ public final class TextClassifierImpl implements TextClassifier {
             return Collections.unmodifiableList(mSupportedLocales);
         }
 
+        public boolean isPreferredTo(ModelFile model) {
+            // A model is preferred to no model.
+            if (model == null) {
+                return true;
+            }
+
+            // A language-specific model is preferred to a language independent
+            // model.
+            if (!mLanguageIndependent && model.mLanguageIndependent) {
+                return true;
+            }
+
+            // A higher-version model is preferred.
+            if (getVersion() > model.getVersion()) {
+                return true;
+            }
+            return false;
+        }
+
         @Override
         public boolean equals(Object other) {
             if (this == other) {
@@ -555,11 +575,13 @@ public final class TextClassifierImpl implements TextClassifier {
                     mPath, mName, mVersion, localesJoiner.toString());
         }
 
-        private ModelFile(String path, String name, int version, List<Locale> supportedLocales) {
+        private ModelFile(String path, String name, int version, List<Locale> supportedLocales,
+                          boolean languageIndependent) {
             mPath = path;
             mName = name;
             mVersion = version;
             mSupportedLocales = supportedLocales;
+            mLanguageIndependent = languageIndependent;
         }
     }