Replace List<Integer> with faster IntArray.

These were uncovered by the recently added EfficientCollections
Error Prone detector, and several of them are in hot codepaths.

Bug: 155703208
Test: make
Change-Id: I4cff2d6b846edc9a7482d21a803117132cbcdadf

4 files changed, 24 insertions, 23 deletions

diff --git a/core/java/com/android/internal/os/KernelCpuThreadReader.java b/core/java/com/android/internal/os/KernelCpuThreadReader.java
index 2ba372a47cf3..0843741d237c 100644
--- a/core/java/com/android/internal/os/KernelCpuThreadReader.java
+++ b/core/java/com/android/internal/os/KernelCpuThreadReader.java
@@ -18,10 +18,10 @@ package com.android.internal.os;
 
 import android.annotation.Nullable;
 import android.os.Process;
+import android.util.IntArray;
 import android.util.Slog;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.ArrayUtils;
 import com.android.internal.util.Preconditions;
 
 import java.io.IOException;
@@ -456,14 +456,14 @@ public class KernelCpuThreadReader {
          * cluster has started.
          */
         private static int[] getClusterStartIndices(long[] frequencies) {
-            ArrayList<Integer> indices = new ArrayList<>();
+            IntArray indices = new IntArray();
             indices.add(0);
             for (int i = 0; i < frequencies.length - 1; i++) {
                 if (frequencies[i] >= frequencies[i + 1]) {
                     indices.add(i + 1);
                 }
             }
-            return ArrayUtils.convertToIntArray(indices);
+            return indices.toArray();
         }
 
         /** Get the index in frequencies where each bucket starts */
@@ -477,7 +477,7 @@ public class KernelCpuThreadReader {
                 return Arrays.copyOfRange(clusterStartIndices, 0, targetNumBuckets);
             }
 
-            ArrayList<Integer> bucketStartIndices = new ArrayList<>();
+            IntArray bucketStartIndices = new IntArray();
             for (int clusterIdx = 0; clusterIdx < numClusters; clusterIdx++) {
                 final int clusterStartIdx = getLowerBound(clusterIdx, clusterStartIndices);
                 final int clusterEndIdx =
@@ -509,7 +509,7 @@ public class KernelCpuThreadReader {
                     bucketStartIndices.add(bucketStartIdx);
                 }
             }
-            return ArrayUtils.convertToIntArray(bucketStartIndices);
+            return bucketStartIndices.toArray();
         }
 
         private static int getLowerBound(int index, int[] startIndices) {
diff --git a/core/java/com/android/internal/os/ProcTimeInStateReader.java b/core/java/com/android/internal/os/ProcTimeInStateReader.java
index 2318473354e2..d54a9c7f3a46 100644
--- a/core/java/com/android/internal/os/ProcTimeInStateReader.java
+++ b/core/java/com/android/internal/os/ProcTimeInStateReader.java
@@ -18,16 +18,11 @@ package com.android.internal.os;
 
 import android.annotation.Nullable;
 import android.os.Process;
-
-import com.android.internal.util.ArrayUtils;
+import android.util.IntArray;
 
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
 
 /**
  * Reads and parses {@code time_in_state} files in the {@code proc} filesystem.
@@ -68,24 +63,25 @@ public class ProcTimeInStateReader {
      * The format of a single line of the {@code time_in_state} file that exports the frequency
      * values
      */
-    private static final List<Integer> TIME_IN_STATE_LINE_FREQUENCY_FORMAT = Arrays.asList(
+    private static final int[] TIME_IN_STATE_LINE_FREQUENCY_FORMAT = new int[] {
             Process.PROC_OUT_LONG | Process.PROC_SPACE_TERM,
             Process.PROC_NEWLINE_TERM
-    );
+    };
 
     /**
      * The format of a single line of the {@code time_in_state} file that exports the time values
      */
-    private static final List<Integer> TIME_IN_STATE_LINE_TIME_FORMAT = Arrays.asList(
+    private static final int[] TIME_IN_STATE_LINE_TIME_FORMAT = new int[] {
             Process.PROC_SPACE_TERM,
             Process.PROC_OUT_LONG | Process.PROC_NEWLINE_TERM
-    );
+    };
 
     /**
      * The format of a header line of the {@code time_in_state} file
      */
-    private static final List<Integer> TIME_IN_STATE_HEADER_LINE_FORMAT =
-            Collections.singletonList(Process.PROC_NEWLINE_TERM);
+    private static final int[] TIME_IN_STATE_HEADER_LINE_FORMAT = new int[] {
+            Process.PROC_NEWLINE_TERM
+    };
 
     /**
      * The format of the {@code time_in_state} file to extract times, defined using {@link
@@ -166,8 +162,8 @@ public class ProcTimeInStateReader {
         // formats. These formats are used to extract either the frequencies or the times from a
         // time_in_state file
         // Also check if each line is a header, and handle this in the created format arrays
-        ArrayList<Integer> timeInStateFrequencyFormat = new ArrayList<>();
-        ArrayList<Integer> timeInStateTimeFormat = new ArrayList<>();
+        IntArray timeInStateFrequencyFormat = new IntArray();
+        IntArray timeInStateTimeFormat = new IntArray();
         int numFrequencies = 0;
         for (int i = 0; i < timeInStateBytes.length; i++) {
             // If the first character of the line is not a digit, we treat it as a header
@@ -194,12 +190,12 @@ public class ProcTimeInStateReader {
         final long[] readLongs = new long[numFrequencies];
         final boolean readSuccess = Process.parseProcLine(
                 timeInStateBytes, 0, timeInStateBytes.length,
-                ArrayUtils.convertToIntArray(timeInStateFrequencyFormat), null, readLongs, null);
+                timeInStateFrequencyFormat.toArray(), null, readLongs, null);
         if (!readSuccess) {
             throw new IOException("Failed to parse time_in_state file");
         }
 
-        mTimeInStateTimeFormat = ArrayUtils.convertToIntArray(timeInStateTimeFormat);
+        mTimeInStateTimeFormat = timeInStateTimeFormat.toArray();
         mFrequenciesKhz = readLongs;
     }
 }
diff --git a/core/java/com/android/internal/util/ArrayUtils.java b/core/java/com/android/internal/util/ArrayUtils.java
index cd69a02d4d2d..7cb19dceed95 100644
--- a/core/java/com/android/internal/util/ArrayUtils.java
+++ b/core/java/com/android/internal/util/ArrayUtils.java
@@ -310,6 +310,10 @@ public class ArrayUtils {
         return total;
     }
 
+    /**
+     * @deprecated use {@code IntArray} instead
+     */
+    @Deprecated
     public static int[] convertToIntArray(List<Integer> list) {
         int[] array = new int[list.size()];
         for (int i = 0; i < list.size(); i++) {
diff --git a/services/core/java/com/android/server/pm/PackageManagerShellCommand.java b/services/core/java/com/android/server/pm/PackageManagerShellCommand.java
index afbf7d3a35af..c356fc72379f 100644
--- a/services/core/java/com/android/server/pm/PackageManagerShellCommand.java
+++ b/services/core/java/com/android/server/pm/PackageManagerShellCommand.java
@@ -96,6 +96,7 @@ import android.system.Os;
 import android.text.TextUtils;
 import android.text.format.DateUtils;
 import android.util.ArraySet;
+import android.util.IntArray;
 import android.util.PrintWriterPrinter;
 import android.util.Slog;
 import android.util.SparseArray;
@@ -1450,7 +1451,7 @@ class PackageManagerShellCommand extends ShellCommand {
         final PrintWriter pw = getOutPrintWriter();
         final int parentSessionId = Integer.parseInt(getNextArg());
 
-        List<Integer> otherSessionIds = new ArrayList<>();
+        IntArray otherSessionIds = new IntArray();
         String opt;
         while ((opt = getNextArg()) != null) {
             otherSessionIds.add(Integer.parseInt(opt));
@@ -1459,7 +1460,7 @@ class PackageManagerShellCommand extends ShellCommand {
             pw.println("Error: At least two sessions are required.");
             return 1;
         }
-        return doInstallAddSession(parentSessionId, ArrayUtils.convertToIntArray(otherSessionIds),
+        return doInstallAddSession(parentSessionId, otherSessionIds.toArray(),
                 true /*logSuccess*/);
     }