Merge "Add PerUidCounter"
diff --git a/staticlibs/framework/com/android/net/module/util/PerUidCounter.java b/staticlibs/framework/com/android/net/module/util/PerUidCounter.java
new file mode 100644
index 0000000..7e0526d
--- /dev/null
+++ b/staticlibs/framework/com/android/net/module/util/PerUidCounter.java
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2022 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.net.module.util;
+
+import android.util.SparseIntArray;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+
+/**
+ * Keeps track of the counters under different uid, fire exception if the counter
+ * exceeded the specified maximum value.
+ *
+ * @hide
+ */
+public class PerUidCounter {
+ private final int mMaxCountPerUid;
+
+ // Map from UID to count that UID has filed.
+ @VisibleForTesting
+ @GuardedBy("mUidToCount")
+ final SparseIntArray mUidToCount = new SparseIntArray();
+
+ /**
+ * Constructor
+ *
+ * @param maxCountPerUid the maximum count per uid allowed
+ */
+ public PerUidCounter(final int maxCountPerUid) {
+ if (maxCountPerUid < 0) {
+ throw new IllegalArgumentException("Maximum counter value cannot be negative");
+ }
+ mMaxCountPerUid = maxCountPerUid;
+ }
+
+ /**
+ * Increments the count of the given uid. Throws an exception if the number
+ * of the counter for the uid exceeds the value of maxCounterPerUid which is the value
+ * passed into the constructor. see: {@link #PerUidCounter(int)}.
+ *
+ * @throws IllegalStateException if the number of counter for the uid exceed
+ * the allowed number.
+ *
+ * @param uid the uid that the counter was made under
+ */
+ public void incrementCountOrThrow(final int uid) {
+ synchronized (mUidToCount) {
+ incrementCountOrThrow(uid, 1 /* numToIncrement */);
+ }
+ }
+
+ public void incrementCountOrThrow(final int uid, final int numToIncrement) {
+ if (numToIncrement <= 0) {
+ throw new IllegalArgumentException("Increment count must be positive");
+ }
+ final long newCount = ((long) mUidToCount.get(uid, 0)) + numToIncrement;
+ if (newCount > mMaxCountPerUid) {
+ throw new IllegalStateException("Uid " + uid + " exceeded its allowed limit");
+ }
+ // Since the count cannot be greater than Integer.MAX_VALUE here,
+ // it is safe to cast to int.
+ mUidToCount.put(uid, (int) newCount);
+ }
+
+ /**
+ * Decrements the count of the given uid. Throws an exception if the number
+ * of the counter goes below zero.
+ *
+ * @throws IllegalStateException if the number of counter for the uid goes below
+ * zero.
+ *
+ * @param uid the uid that the count was made under
+ */
+ public void decrementCountOrThrow(final int uid) {
+ synchronized (mUidToCount) {
+ decrementCountOrThrow(uid, 1 /* numToDecrement */);
+ }
+ }
+
+ public void decrementCountOrThrow(final int uid, final int numToDecrement) {
+ if (numToDecrement <= 0) {
+ throw new IllegalArgumentException("Decrement count must be positive");
+ }
+ final int newCount = mUidToCount.get(uid, 0) - numToDecrement;
+ if (newCount < 0) {
+ throw new IllegalStateException("BUG: too small count " + newCount + " for UID " + uid);
+ } else if (newCount == 0) {
+ mUidToCount.delete(uid);
+ } else {
+ mUidToCount.put(uid, newCount);
+ }
+ }
+}
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/PerUidCounterTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/PerUidCounterTest.kt
new file mode 100644
index 0000000..c479d81
--- /dev/null
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/PerUidCounterTest.kt
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2022 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.net.module.util
+
+import androidx.test.filters.SmallTest
+import androidx.test.runner.AndroidJUnit4
+import org.junit.Test
+import org.junit.runner.RunWith
+import kotlin.test.assertFailsWith
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class PerUidCounterTest {
+ private val UID_A = 1000
+ private val UID_B = 1001
+
+ @Test
+ fun testCounterMaximum() {
+ assertFailsWith<IllegalArgumentException> {
+ PerUidCounter(-1)
+ }
+
+ val uselessCounter = PerUidCounter(0)
+ assertFailsWith<IllegalStateException> {
+ uselessCounter.incrementCountOrThrow(UID_A)
+ }
+ assertFailsWith<IllegalStateException> {
+ uselessCounter.decrementCountOrThrow(UID_A)
+ }
+
+ val largeMaxCounter = PerUidCounter(Integer.MAX_VALUE)
+ largeMaxCounter.incrementCountOrThrow(UID_A, Integer.MAX_VALUE)
+ assertFailsWith<IllegalStateException> {
+ largeMaxCounter.incrementCountOrThrow(UID_A)
+ }
+ }
+
+ @Test
+ fun testIncrementCountOrThrow() {
+ val counter = PerUidCounter(3)
+
+ // Verify the increment count cannot be zero.
+ assertFailsWith<IllegalArgumentException> {
+ counter.incrementCountOrThrow(UID_A, 0)
+ }
+
+ // Verify the counters work independently.
+ counter.incrementCountOrThrow(UID_A)
+ counter.incrementCountOrThrow(UID_B, 2)
+ counter.incrementCountOrThrow(UID_B)
+ counter.incrementCountOrThrow(UID_A)
+ counter.incrementCountOrThrow(UID_A)
+ assertFailsWith<IllegalStateException> {
+ counter.incrementCountOrThrow(UID_A)
+ }
+ assertFailsWith<IllegalStateException> {
+ counter.incrementCountOrThrow(UID_B)
+ }
+
+ // Verify exception can be triggered again.
+ assertFailsWith<IllegalStateException> {
+ counter.incrementCountOrThrow(UID_A)
+ }
+ assertFailsWith<IllegalStateException> {
+ counter.incrementCountOrThrow(UID_A, 3)
+ }
+ }
+
+ @Test
+ fun testDecrementCountOrThrow() {
+ val counter = PerUidCounter(3)
+
+ // Verify the decrement count cannot be zero.
+ assertFailsWith<IllegalArgumentException> {
+ counter.decrementCountOrThrow(UID_A, 0)
+ }
+
+ // Verify the count cannot go below zero.
+ assertFailsWith<IllegalStateException> {
+ counter.decrementCountOrThrow(UID_A)
+ }
+ assertFailsWith<IllegalStateException> {
+ counter.decrementCountOrThrow(UID_A, 5)
+ }
+ assertFailsWith<IllegalStateException> {
+ counter.decrementCountOrThrow(UID_A, Integer.MAX_VALUE)
+ }
+
+ // Verify the counters work independently.
+ counter.incrementCountOrThrow(UID_A)
+ counter.incrementCountOrThrow(UID_B)
+ assertFailsWith<IllegalStateException> {
+ counter.decrementCountOrThrow(UID_A, 3)
+ }
+ counter.decrementCountOrThrow(UID_A)
+ assertFailsWith<IllegalStateException> {
+ counter.decrementCountOrThrow(UID_A)
+ }
+ }
+}
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