Import Android SDK Platform P [4697573]

/google/data/ro/projects/android/fetch_artifact \
    --bid 4697573 \
    --target sdk_phone_armv7-win_sdk \
    sdk-repo-linux-sources-4697573.zip

AndroidVersion.ApiLevel has been modified to appear as 28

Change-Id: If80578c3c657366cc9cf75f8db13d46e2dd4e077

4 files changed, 116 insertions, 53 deletions

diff --git a/android/ext/services/autofill/AutofillFieldClassificationServiceImpl.java b/android/ext/services/autofill/AutofillFieldClassificationServiceImpl.java
index 4709d350..9ba7e092 100644
--- a/android/ext/services/autofill/AutofillFieldClassificationServiceImpl.java
+++ b/android/ext/services/autofill/AutofillFieldClassificationServiceImpl.java
@@ -15,6 +15,8 @@
  */
 package android.ext.services.autofill;
 
+import static android.ext.services.autofill.EditDistanceScorer.DEFAULT_ALGORITHM;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.os.Bundle;
@@ -29,8 +31,6 @@ import java.util.List;
 public class AutofillFieldClassificationServiceImpl extends AutofillFieldClassificationService {
 
     private static final String TAG = "AutofillFieldClassificationServiceImpl";
-    // TODO(b/70291841): set to false before launching
-    private static final boolean DEBUG = true;
 
     @Nullable
     @Override
@@ -40,30 +40,13 @@ public class AutofillFieldClassificationServiceImpl extends AutofillFieldClassif
         if (ArrayUtils.isEmpty(actualValues) || ArrayUtils.isEmpty(userDataValues)) {
             Log.w(TAG, "getScores(): empty currentvalues (" + actualValues + ") or userValues ("
                     + userDataValues + ")");
-            // TODO(b/70939974): add unit test
             return null;
         }
-        if (algorithmName != null && !algorithmName.equals(EditDistanceScorer.NAME)) {
+        if (algorithmName != null && !algorithmName.equals(DEFAULT_ALGORITHM)) {
             Log.w(TAG, "Ignoring invalid algorithm (" + algorithmName + ") and using "
-                    + EditDistanceScorer.NAME + " instead");
-        }
-
-        final String actualAlgorithmName = EditDistanceScorer.NAME;
-        final int actualValuesSize = actualValues.size();
-        final int userDataValuesSize = userDataValues.size();
-        if (DEBUG) {
-            Log.d(TAG, "getScores() will return a " + actualValuesSize + "x"
-                    + userDataValuesSize + " matrix for " + actualAlgorithmName);
+                    + DEFAULT_ALGORITHM + " instead");
         }
-        final float[][] scores = new float[actualValuesSize][userDataValuesSize];
 
-        final EditDistanceScorer algorithm = EditDistanceScorer.getInstance();
-        for (int i = 0; i < actualValuesSize; i++) {
-            for (int j = 0; j < userDataValuesSize; j++) {
-                final float score = algorithm.getScore(actualValues.get(i), userDataValues.get(j));
-                scores[i][j] = score;
-            }
-        }
-        return scores;
+        return EditDistanceScorer.getScores(actualValues, userDataValues);
     }
 }
diff --git a/android/ext/services/autofill/EditDistanceScorer.java b/android/ext/services/autofill/EditDistanceScorer.java
index d2e804af..302b1602 100644
--- a/android/ext/services/autofill/EditDistanceScorer.java
+++ b/android/ext/services/autofill/EditDistanceScorer.java
@@ -16,53 +16,133 @@
 package android.ext.services.autofill;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.util.Log;
 import android.view.autofill.AutofillValue;
 
-/**
- * Helper used to calculate the classification score between an actual {@link AutofillValue} filled
- * by the user and the expected value predicted by an autofill service.
- */
-// TODO(b/70291841): explain algorithm once it's fully implemented
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.util.List;
+
 final class EditDistanceScorer {
 
-    private static final EditDistanceScorer sInstance = new EditDistanceScorer();
+    private static final String TAG = "EditDistanceScorer";
+
+    // TODO(b/70291841): STOPSHIP - set to false before launching
+    private static final boolean DEBUG = true;
 
-    public static final String NAME = "EDIT_DISTANCE";
+    static final String DEFAULT_ALGORITHM = "EDIT_DISTANCE";
 
     /**
-     * Gets the singleton instance.
+     * Gets the field classification score of 2 values based on the edit distance between them.
+     *
+     * <p>The score is defined as: @(max_length - edit_distance) / max_length
      */
-    public static EditDistanceScorer getInstance() {
-        return sInstance;
+    @VisibleForTesting
+    static float getScore(@Nullable AutofillValue actualValue, @Nullable String userDataValue) {
+        if (actualValue == null || !actualValue.isText() || userDataValue == null) return 0;
+
+        final String actualValueText = actualValue.getTextValue().toString();
+        final int actualValueLength = actualValueText.length();
+        final int userDatalength = userDataValue.length();
+        if (userDatalength == 0) {
+            return (actualValueLength == 0) ? 1 : 0;
+        }
+
+        final int distance = editDistance(actualValueText.toLowerCase(),
+                userDataValue.toLowerCase());
+        final int maxLength = Math.max(actualValueLength, userDatalength);
+        return ((float) maxLength - distance) / maxLength;
     }
 
-    private EditDistanceScorer() {
+    /**
+     * Computes the edit distance (number of insertions, deletions or substitutions to edit one
+     * string into the other) between two strings. In particular, this will compute the Levenshtein
+     * distance.
+     *
+     * <p>See http://en.wikipedia.org/wiki/Levenshtein_distance for details.
+     *
+     * @param s the first string to compare
+     * @param t the second string to compare
+     * @return the edit distance between the two strings
+     */
+    // Note: copied verbatim from com.android.tools.lint.detector.api.LintUtils.java
+    public static int editDistance(@NonNull String s, @NonNull String t) {
+        return editDistance(s, t, Integer.MAX_VALUE);
     }
 
     /**
-     * Returns the classification score between an actual {@link AutofillValue} filled
-     * by the user and the expected value predicted by an autofill service.
+     * Computes the edit distance (number of insertions, deletions or substitutions to edit one
+     * string into the other) between two strings. In particular, this will compute the Levenshtein
+     * distance.
      *
-     * <p>A full-match is {@code 1.0} (representing 100%), a full mismatch is {@code 0.0} and
-     * partial mathces are something in between, typically using edit-distance algorithms.
+     * <p>See http://en.wikipedia.org/wiki/Levenshtein_distance for details.
      *
+     * @param s the first string to compare
+     * @param t the second string to compare
+     * @param max the maximum edit distance that we care about; if for example the string length
+     *     delta is greater than this we don't bother computing the exact edit distance since the
+     *     caller has indicated they're not interested in the result
+     * @return the edit distance between the two strings, or some other value greater than that if
+     *     the edit distance is at least as big as the {@code max} parameter
      */
-    public float getScore(@NonNull AutofillValue actualValue, @NonNull String userDataValue) {
-        if (actualValue == null || !actualValue.isText() || userDataValue == null) return 0;
-        // TODO(b/70291841): implement edit distance - currently it's returning either 0, 100%, or
-        // partial match when number of chars match
-        final String textValue = actualValue.getTextValue().toString();
-        final int total = textValue.length();
-        if (total != userDataValue.length()) return 0F;
-
-        int matches = 0;
-        for (int i = 0; i < total; i++) {
-            if (Character.toLowerCase(textValue.charAt(i)) == Character
-                    .toLowerCase(userDataValue.charAt(i))) {
-                matches++;
+    // Note: copied verbatim from com.android.tools.lint.detector.api.LintUtils.java
+    private static int editDistance(@NonNull String s, @NonNull String t, int max) {
+        if (s.equals(t)) {
+            return 0;
+        }
+
+        if (Math.abs(s.length() - t.length()) > max) {
+            // The string lengths differ more than the allowed edit distance;
+            // no point in even attempting to compute the edit distance (requires
+            // O(n*m) storage and O(n*m) speed, where n and m are the string lengths)
+            return Integer.MAX_VALUE;
+        }
+
+        int m = s.length();
+        int n = t.length();
+        int[][] d = new int[m + 1][n + 1];
+        for (int i = 0; i <= m; i++) {
+            d[i][0] = i;
+        }
+        for (int j = 0; j <= n; j++) {
+            d[0][j] = j;
+        }
+        for (int j = 1; j <= n; j++) {
+            for (int i = 1; i <= m; i++) {
+                if (s.charAt(i - 1) == t.charAt(j - 1)) {
+                    d[i][j] = d[i - 1][j - 1];
+                } else {
+                    int deletion = d[i - 1][j] + 1;
+                    int insertion = d[i][j - 1] + 1;
+                    int substitution = d[i - 1][j - 1] + 1;
+                    d[i][j] = Math.min(deletion, Math.min(insertion, substitution));
+                }
             }
         }
 
-        return ((float) matches) / total;
+        return d[m][n];
+    }
+    /**
+     * Gets the scores in a batch.
+     */
+    static float[][] getScores(@NonNull List<AutofillValue> actualValues,
+            @NonNull List<String> userDataValues) {
+        final int actualValuesSize = actualValues.size();
+        final int userDataValuesSize = userDataValues.size();
+        if (DEBUG) {
+            Log.d(TAG, "getScores() will return a " + actualValuesSize + "x"
+                    + userDataValuesSize + " matrix for " + DEFAULT_ALGORITHM);
+        }
+        final float[][] scores = new float[actualValuesSize][userDataValuesSize];
+
+        for (int i = 0; i < actualValuesSize; i++) {
+            for (int j = 0; j < userDataValuesSize; j++) {
+                final float score = getScore(actualValues.get(i), userDataValues.get(j));
+                scores[i][j] = score;
+            }
+        }
+        return scores;
     }
+
 }
diff --git a/android/ext/services/notification/Assistant.java b/android/ext/services/notification/Assistant.java
index 6fe89755..9a66b07f 100644
--- a/android/ext/services/notification/Assistant.java
+++ b/android/ext/services/notification/Assistant.java
@@ -94,7 +94,7 @@ public class Assistant extends NotificationAssistantService {
                 infile = mFile.openRead();
                 readXml(infile);
             } catch (FileNotFoundException e) {
-                // No data yet
+                Log.d(TAG, "File doesn't exist or isn't readable yet");
             } catch (IOException e) {
                 Log.e(TAG, "Unable to read channel impressions", e);
             } catch (NumberFormatException | XmlPullParserException e) {
diff --git a/android/ext/services/notification/ChannelImpressions.java b/android/ext/services/notification/ChannelImpressions.java
index 4ad4b241..de2659f4 100644
--- a/android/ext/services/notification/ChannelImpressions.java
+++ b/android/ext/services/notification/ChannelImpressions.java
@@ -30,7 +30,7 @@ public final class ChannelImpressions implements Parcelable {
     private static final String TAG = "ExtAssistant.CI";
     private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
 
-    static final double DISMISS_TO_VIEW_RATIO_LIMIT = .8;
+    static final double DISMISS_TO_VIEW_RATIO_LIMIT = .4;
     static final int STREAK_LIMIT = 2;
     static final String ATT_DISMISSALS = "dismisses";
     static final String ATT_VIEWS = "views";