Merge "Add lint recycle detector"

9 files changed, 737 insertions, 19 deletions

diff --git a/lint/cli/.classpath b/lint/cli/.classpath
index ade4f41..3278842 100644
--- a/lint/cli/.classpath
+++ b/lint/cli/.classpath
@@ -5,11 +5,11 @@
 	<classpathentry combineaccessrules="false" kind="src" path="/common"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/lint-api"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/lint-checks"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-analysis-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-analysis-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src-4.0.zip"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/SdkLib"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>
diff --git a/lint/cli/src/test/.classpath b/lint/cli/src/test/.classpath
index 178cd8c..e79b65f 100644
--- a/lint/cli/src/test/.classpath
+++ b/lint/cli/src/test/.classpath
@@ -7,10 +7,10 @@
 	<classpathentry combineaccessrules="false" kind="src" path="/lint-api"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/lint-checks"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/lint-cli"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src-4.0.zip"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/layoutlib_api"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/common"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/testutils"/>
diff --git a/lint/cli/src/test/java/com/android/tools/lint/checks/RecycleDetectorTest.java b/lint/cli/src/test/java/com/android/tools/lint/checks/RecycleDetectorTest.java
new file mode 100644
index 0000000..ebef046
--- /dev/null
+++ b/lint/cli/src/test/java/com/android/tools/lint/checks/RecycleDetectorTest.java
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2012 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.tools.lint.checks;
+
+import com.android.tools.lint.detector.api.Detector;
+
+@SuppressWarnings("javadoc")
+public class RecycleDetectorTest extends AbstractCheckTest {
+    @Override
+    protected Detector getDetector() {
+        return new RecycleDetector();
+    }
+
+    public void test() throws Exception {
+        assertEquals(
+            "src/test/pkg/RecycleTest.java:56: Warning: This TypedArray should be recycled after use with #recycle() [Recycle]\n" +
+            "  final TypedArray a = getContext().obtainStyledAttributes(attrs,\n" +
+            "                                    ~~~~~~~~~~~~~~~~~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:63: Warning: This TypedArray should be recycled after use with #recycle() [Recycle]\n" +
+            "  final TypedArray a = getContext().obtainStyledAttributes(new int[0]);\n" +
+            "                                    ~~~~~~~~~~~~~~~~~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:79: Warning: This VelocityTracker should be recycled after use with #recycle() [Recycle]\n" +
+            "  VelocityTracker tracker = VelocityTracker.obtain();\n" +
+            "                                            ~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:85: Warning: This Message should be recycled after use with #recycle() [Recycle]\n" +
+            "  Message message1 = getHandler().obtainMessage();\n" +
+            "                                  ~~~~~~~~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:86: Warning: This Message should be recycled after use with #recycle() [Recycle]\n" +
+            "  Message message2 = Message.obtain();\n" +
+            "                             ~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:92: Warning: This MotionEvent should be recycled after use with #recycle() [Recycle]\n" +
+            "  MotionEvent event1 = MotionEvent.obtain(null);\n" +
+            "                                   ~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:93: Warning: This MotionEvent should be recycled after use with #recycle() [Recycle]\n" +
+            "  MotionEvent event2 = MotionEvent.obtainNoHistory(null);\n" +
+            "                                   ~~~~~~~~~~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:98: Warning: This MotionEvent should be recycled after use with #recycle() [Recycle]\n" +
+            "  MotionEvent event2 = MotionEvent.obtainNoHistory(null); // Not recycled\n" +
+            "                                   ~~~~~~~~~~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:103: Warning: This MotionEvent should be recycled after use with #recycle() [Recycle]\n" +
+            "  MotionEvent event1 = MotionEvent.obtain(null);  // Not recycled\n" +
+            "                                   ~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:113: Warning: This MotionEvent has already been recycled [Recycle]\n" +
+            "  int contents2 = event1.describeContents(); // BAD, after recycle\n" +
+            "                         ~~~~~~~~~~~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:117: Warning: This TypedArray has already been recycled [Recycle]\n" +
+            "  example = a.getString(R.styleable.MyView_exampleString); // BAD, after recycle\n" +
+            "              ~~~~~~~~~\n" +
+            "src/test/pkg/RecycleTest.java:129: Warning: This Parcel should be recycled after use with #recycle() [Recycle]\n" +
+            "  Parcel myparcel = Parcel.obtain();\n" +
+            "                           ~~~~~~\n" +
+            "0 errors, 12 warnings\n",
+
+            lintProject(
+                "apicheck/classpath=>.classpath",
+                "apicheck/minsdk4.xml=>AndroidManifest.xml",
+                "project.properties1=>project.properties",
+                "bytecode/RecycleTest.java.txt=>src/test/pkg/RecycleTest.java",
+                "bytecode/RecycleTest.class.data=>bin/classes/test/pkg/RecycleTest.class"
+            ));
+    }
+}
diff --git a/lint/cli/src/test/java/com/android/tools/lint/checks/data/bytecode/RecycleTest.class.data b/lint/cli/src/test/java/com/android/tools/lint/checks/data/bytecode/RecycleTest.class.data
new file mode 100644
index 0000000..3bdc829
--- /dev/null
+++ b/lint/cli/src/test/java/com/android/tools/lint/checks/data/bytecode/RecycleTest.class.data
diff --git a/lint/cli/src/test/java/com/android/tools/lint/checks/data/bytecode/RecycleTest.java.txt b/lint/cli/src/test/java/com/android/tools/lint/checks/data/bytecode/RecycleTest.java.txt
new file mode 100644
index 0000000..2a026f2
--- /dev/null
+++ b/lint/cli/src/test/java/com/android/tools/lint/checks/data/bytecode/RecycleTest.java.txt
@@ -0,0 +1,159 @@
+package test.pkg;
+
+import com.unit.test.R;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.os.Message;
+import android.os.Parcel;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.view.VelocityTracker;
+import android.view.View;
+
+@SuppressWarnings("unused")
+public class RecycleTest extends View {
+	// ---- Check recycling TypedArrays ----
+
+	public RecycleTest(Context context, AttributeSet attrs, int defStyle) {
+		super(context, attrs, defStyle);
+	}
+
+	public void ok1(AttributeSet attrs, int defStyle) {
+		final TypedArray a = getContext().obtainStyledAttributes(attrs,
+				R.styleable.MyView, defStyle, 0);
+		String example = a.getString(R.styleable.MyView_exampleString);
+		a.recycle();
+	}
+
+	public void ok2(AttributeSet attrs, int defStyle) {
+		final TypedArray a = getContext().obtainStyledAttributes(attrs,
+				R.styleable.MyView, defStyle, 0);
+		String example = a.getString(R.styleable.MyView_exampleString);
+		// If there's complicated logic, don't flag
+		if (something()) {
+			a.recycle();
+		}
+	}
+
+	public TypedArray ok3(AttributeSet attrs, int defStyle) {
+		// Value passes out of method: don't flag, caller might be recycling
+		return getContext().obtainStyledAttributes(attrs, R.styleable.MyView,
+				defStyle, 0);
+	}
+
+	private TypedArray myref;
+
+	public void ok4(AttributeSet attrs, int defStyle) {
+		// Value stored in a field: might be recycled later
+		TypedArray ref = getContext().obtainStyledAttributes(attrs,
+				R.styleable.MyView, defStyle, 0);
+		myref = ref;
+	}
+
+	public void wrong1(AttributeSet attrs, int defStyle) {
+		final TypedArray a = getContext().obtainStyledAttributes(attrs,
+				R.styleable.MyView, defStyle, 0);
+		String example = a.getString(R.styleable.MyView_exampleString);
+		// a.recycle();
+	}
+
+	public void wrong2(AttributeSet attrs, int defStyle) {
+		final TypedArray a = getContext().obtainStyledAttributes(new int[0]);
+		// a.recycle();
+	}
+
+	public void unknown(AttributeSet attrs, int defStyle) {
+		final TypedArray a = getContext().obtainStyledAttributes(attrs,
+				R.styleable.MyView, defStyle, 0);
+		// We don't know what this method is (usually it will be in a different
+		// class)
+		// so don't flag it; it might recycle
+		handle(a);
+	}
+
+	// ---- Check recycling VelocityTracker ----
+
+	public void tracker() {
+		VelocityTracker tracker = VelocityTracker.obtain();
+	}
+
+	// ---- Check recycling Message ----
+
+	public void message() {
+		Message message1 = getHandler().obtainMessage();
+		Message message2 = Message.obtain();
+	}
+
+	// ---- Check recycling MotionEvent ----
+
+	public void motionEvent() {
+		MotionEvent event1 = MotionEvent.obtain(null);
+		MotionEvent event2 = MotionEvent.obtainNoHistory(null);
+	}
+
+	public void motionEvent2() {
+		MotionEvent event1 = MotionEvent.obtain(null); // OK
+		MotionEvent event2 = MotionEvent.obtainNoHistory(null); // Not recycled
+		event1.recycle();
+	}
+
+	public void motionEvent3() {
+		MotionEvent event1 = MotionEvent.obtain(null);  // Not recycled
+		MotionEvent event2 = MotionEvent.obtain(event1);
+		event2.recycle();
+	}
+
+	// ---- Using recycled objects ----
+
+	public void recycled() {
+		MotionEvent event1 = MotionEvent.obtain(null);  // Not recycled
+		event1.recycle();
+		int contents2 = event1.describeContents(); // BAD, after recycle
+		final TypedArray a = getContext().obtainStyledAttributes(new int[0]);
+		String example = a.getString(R.styleable.MyView_exampleString); // OK
+		a.recycle();
+		example = a.getString(R.styleable.MyView_exampleString); // BAD, after recycle
+	}
+
+	// ---- Check recycling Parcel ----
+
+	public void parcelOk() {
+		Parcel myparcel = Parcel.obtain();
+		myparcel.createBinderArray();
+		myparcel.recycle();
+	}
+
+	public void parcelMissing() {
+		Parcel myparcel = Parcel.obtain();
+		myparcel.createBinderArray();
+	}
+
+
+	// ---- Check suppress ----
+
+	@SuppressLint("Recycle")
+	public void recycledSuppress() {
+		MotionEvent event1 = MotionEvent.obtain(null);  // Not recycled
+		event1.recycle();
+		int contents2 = event1.describeContents(); // BAD, after recycle
+		final TypedArray a = getContext().obtainStyledAttributes(new int[0]);
+		String example = a.getString(R.styleable.MyView_exampleString); // OK
+	}
+
+	// ---- Stubs ----
+
+	static void handle(TypedArray a) {
+		// Unknown method
+	}
+
+	protected boolean something() {
+		return true;
+	}
+
+	public android.content.res.TypedArray obtainStyledAttributes(
+			AttributeSet set, int[] attrs, int defStyleAttr, int defStyleRes) {
+		return null;
+	}
+}
diff --git a/lint/libs/lint_api/.classpath b/lint/libs/lint_api/.classpath
index 426f226..b9f0a8a 100644
--- a/lint/libs/lint_api/.classpath
+++ b/lint/libs/lint_api/.classpath
@@ -3,10 +3,10 @@
 	<classpathentry excluding="Android.mk" kind="src" path="src/main/java"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/common"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src-4.0.zip"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/layoutlib_api"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/SdkLib"/>
 	<classpathentry kind="output" path="bin"/>
diff --git a/lint/libs/lint_checks/.classpath b/lint/libs/lint_checks/.classpath
index b169864..51eb645 100644
--- a/lint/libs/lint_checks/.classpath
+++ b/lint/libs/lint_checks/.classpath
@@ -3,11 +3,11 @@
 	<classpathentry kind="src" path="src/main/java"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/lint-api"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-analysis-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src.zip"/>
-	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-tree-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/asm-tools/asm-analysis-4.0.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/asm-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/guava-tools/guava-13.0.1.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/guava-tools/src-4.0.zip"/>
+	<classpathentry kind="var" path="ANDROID_SRC/prebuilts/tools/common/lombok-ast/lombok-ast-0.2.jar" sourcepath="/ANDROID_SRC/prebuilts/tools/common/lombok-ast/src-4.0.zip"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/layoutlib_api"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/common"/>
 	<classpathentry combineaccessrules="false" kind="src" path="/SdkLib"/>
diff --git a/lint/libs/lint_checks/src/main/java/com/android/tools/lint/checks/BuiltinIssueRegistry.java b/lint/libs/lint_checks/src/main/java/com/android/tools/lint/checks/BuiltinIssueRegistry.java
index 254cb02..39a5ae3 100644
--- a/lint/libs/lint_checks/src/main/java/com/android/tools/lint/checks/BuiltinIssueRegistry.java
+++ b/lint/libs/lint_checks/src/main/java/com/android/tools/lint/checks/BuiltinIssueRegistry.java
@@ -55,7 +55,7 @@ public class BuiltinIssueRegistry extends IssueRegistry {
     private static final List<Issue> sIssues;
 
     static {
-        final int initialCapacity = 133;
+        final int initialCapacity = 134;
         List<Issue> issues = new ArrayList<Issue>(initialCapacity);
 
         issues.add(AccessibilityDetector.ISSUE);
@@ -182,6 +182,7 @@ public class BuiltinIssueRegistry extends IssueRegistry {
         issues.add(JavaPerformanceDetector.USE_VALUEOF);
         issues.add(JavaPerformanceDetector.USE_SPARSEARRAY);
         issues.add(WakelockDetector.ISSUE);
+        issues.add(RecycleDetector.ISSUE);
         issues.add(SetJavaScriptEnabledDetector.ISSUE);
         issues.add(ToastDetector.ISSUE);
         issues.add(SharedPrefsDetector.ISSUE);
diff --git a/lint/libs/lint_checks/src/main/java/com/android/tools/lint/checks/RecycleDetector.java b/lint/libs/lint_checks/src/main/java/com/android/tools/lint/checks/RecycleDetector.java
new file mode 100644
index 0000000..cad354c
--- /dev/null
+++ b/lint/libs/lint_checks/src/main/java/com/android/tools/lint/checks/RecycleDetector.java
@@ -0,0 +1,482 @@
+/*
+ * Copyright (C) 2012 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.tools.lint.checks;
+
+import com.android.annotations.NonNull;
+import com.android.annotations.Nullable;
+import com.android.tools.lint.detector.api.Category;
+import com.android.tools.lint.detector.api.ClassContext;
+import com.android.tools.lint.detector.api.Context;
+import com.android.tools.lint.detector.api.Detector;
+import com.android.tools.lint.detector.api.Detector.ClassScanner;
+import com.android.tools.lint.detector.api.Issue;
+import com.android.tools.lint.detector.api.Location;
+import com.android.tools.lint.detector.api.Scope;
+import com.android.tools.lint.detector.api.Severity;
+
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.Type;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.ClassNode;
+import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.tree.analysis.Analyzer;
+import org.objectweb.asm.tree.analysis.AnalyzerException;
+import org.objectweb.asm.tree.analysis.BasicValue;
+import org.objectweb.asm.tree.analysis.Frame;
+import org.objectweb.asm.tree.analysis.Interpreter;
+import org.objectweb.asm.tree.analysis.Value;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Checks for missing {@code recycle} calls on resources that encourage it
+ */
+public class RecycleDetector extends Detector implements ClassScanner {
+    /** Problems with missing recycle calls */
+    public static final Issue ISSUE = Issue.create(
+        "Recycle", //$NON-NLS-1$
+        "Looks for missing recycle() calls on resources",
+
+        "Many resources, such as TypedArrays, VelocityTrackers, etc., " +
+        "should be recycled (with a `recycle()` call) after use. This lint check looks " +
+        "for missing `recycle()` calls.",
+
+        Category.PERFORMANCE,
+        7,
+        Severity.WARNING,
+        RecycleDetector.class,
+        Scope.CLASS_FILE_SCOPE);
+
+    // Target method names
+    private static final String RECYCLE = "recycle";                                  //$NON-NLS-1$
+    private static final String OBTAIN = "obtain";                                    //$NON-NLS-1$
+    private static final String OBTAIN_NO_HISTORY = "obtainNoHistory";                //$NON-NLS-1$
+    private static final String OBTAIN_MESSAGE = "obtainMessage";                     //$NON-NLS-1$
+    private static final String OBTAIN_ATTRIBUTES = "obtainAttributes";               //$NON-NLS-1$
+    private static final String OBTAIN_TYPED_ARRAY = "obtainTypedArray";              //$NON-NLS-1$
+    private static final String OBTAIN_STYLED_ATTRIBUTES = "obtainStyledAttributes";  //$NON-NLS-1$
+
+    // Target owners
+    private static final String VELOCITY_TRACKER_CLS = "android/view/VelocityTracker";//$NON-NLS-1$
+    private static final String TYPED_ARRAY_CLS = "android/content/res/TypedArray";   //$NON-NLS-1$
+    private static final String CONTEXT_CLS = "android/content/Context";              //$NON-NLS-1$
+    private static final String MOTION_EVENT_CLS = "android/view/MotionEvent";        //$NON-NLS-1$
+    private static final String MESSAGE_CLS = "android/os/Message";                   //$NON-NLS-1$
+    private static final String HANDLER_CLS = "android/os/Handler";                   //$NON-NLS-1$
+    private static final String RESOURCES_CLS = "android/content/res/Resources";      //$NON-NLS-1$
+    private static final String PARCEL_CLS = "android/os/Parcel";                     //$NON-NLS-1$
+
+    // Target description signatures
+    private static final String TYPED_ARRAY_SIG = "Landroid/content/res/TypedArray;"; //$NON-NLS-1$
+    private static final String MESSAGE_SIG = "Landroid/os/Message;";                 //$NON-NLS-1$
+
+    private boolean mObtainsTypedArray;
+    private boolean mRecyclesTypedArray;
+    private boolean mObtainsTracker;
+    private boolean mRecyclesTracker;
+    private boolean mObtainsMessage;
+    private boolean mRecyclesMessage;
+    private boolean mObtainsMotionEvent;
+    private boolean mRecyclesMotionEvent;
+    private boolean mObtainsParcel;
+    private boolean mRecyclesParcel;
+
+    /** Constructs a new {@link RecycleDetector} */
+    public RecycleDetector() {
+    }
+
+    @Override
+    public void afterCheckProject(@NonNull Context context) {
+        int phase = context.getDriver().getPhase();
+        if (phase == 1) {
+            if (mObtainsTypedArray && !mRecyclesTypedArray
+                    || mObtainsTracker && !mRecyclesTracker
+                    || mObtainsMessage && !mRecyclesMessage
+                    || mObtainsParcel && !mRecyclesParcel
+                    || mObtainsMotionEvent && !mRecyclesMotionEvent) {
+                context.getDriver().requestRepeat(this, Scope.CLASS_FILE_SCOPE);
+            }
+        }
+    }
+
+    // ---- Implements ClassScanner ----
+
+    @Override
+    @Nullable
+    public List<String> getApplicableCallNames() {
+        return Arrays.asList(
+                RECYCLE,
+                OBTAIN_STYLED_ATTRIBUTES,
+                OBTAIN,
+                OBTAIN_ATTRIBUTES,
+                OBTAIN_TYPED_ARRAY,
+                OBTAIN_MESSAGE,
+                OBTAIN_NO_HISTORY
+        );
+    }
+
+    @Override
+    public void checkCall(
+            @NonNull ClassContext context,
+            @NonNull ClassNode classNode,
+            @NonNull MethodNode method,
+            @NonNull MethodInsnNode call) {
+        String name = call.name;
+        String owner = call.owner;
+        String desc = call.desc;
+        int phase = context.getDriver().getPhase();
+        if (RECYCLE.equals(name) && desc.equals("()V")) { //$NON-NLS-1$
+            if (owner.equals(TYPED_ARRAY_CLS)) {
+                mRecyclesTypedArray = true;
+            } else if (owner.equals(VELOCITY_TRACKER_CLS)) {
+                mRecyclesTracker = true;
+            } else if (owner.equals(MESSAGE_CLS)) {
+                mRecyclesMessage = true;
+            } else if (owner.equals(MOTION_EVENT_CLS)) {
+                mRecyclesMotionEvent = true;
+            } else if (owner.equals(PARCEL_CLS)) {
+                mRecyclesParcel = true;
+            }
+        } else if (owner.equals(MOTION_EVENT_CLS)) {
+            if (OBTAIN.equals(name) || OBTAIN_NO_HISTORY.equals(name)) {
+                mObtainsMotionEvent = true;
+                if (phase == 2 && !mRecyclesMotionEvent) {
+                    context.report(ISSUE, method, call, context.getLocation(call),
+                            getErrorMessage(MOTION_EVENT_CLS),
+                            null);
+                } else if (phase == 1
+                        && checkMethodFlow(context, classNode, method, call, MOTION_EVENT_CLS)) {
+                    // Already reported error above; don't do global check
+                    mRecyclesMotionEvent = true;
+                }
+            }
+        } else if (OBTAIN_MESSAGE.equals(name)) {
+            if (owner.equals(HANDLER_CLS) && desc.endsWith(MESSAGE_SIG)) {
+                mObtainsMessage = true;
+                if (phase == 2 && !mRecyclesMessage) {
+                    context.report(ISSUE, method, call, context.getLocation(call),
+                            getErrorMessage(MESSAGE_CLS), null);
+                }
+            }
+        } else if (OBTAIN.equals(name)) {
+            if (owner.equals(VELOCITY_TRACKER_CLS)) {
+                mObtainsTracker = true;
+                if (phase == 2 && !mRecyclesTracker) {
+                    context.report(ISSUE, method, call, context.getLocation(call),
+                            getErrorMessage(VELOCITY_TRACKER_CLS),
+                            null);
+                }
+            } else if (owner.equals(MESSAGE_CLS) && desc.endsWith(MESSAGE_SIG)) {
+                // TODO: Handle Message constructor?
+                mObtainsMessage = true;
+                if (phase == 2 && !mRecyclesMessage) {
+                    context.report(ISSUE, method, call, context.getLocation(call),
+                            getErrorMessage(MESSAGE_CLS),
+                            null);
+                }
+            } else if (owner.equals(PARCEL_CLS)) {
+                mObtainsParcel = true;
+                if (phase == 2 && !mRecyclesParcel) {
+                    context.report(ISSUE, method, call, context.getLocation(call),
+                            getErrorMessage(PARCEL_CLS),
+                            null);
+                } else if (phase == 1
+                        && checkMethodFlow(context, classNode, method, call, PARCEL_CLS)) {
+                    // Already reported error above; don't do global check
+                    mRecyclesParcel = true;
+                }
+            }
+        } else if (OBTAIN_STYLED_ATTRIBUTES.equals(name)
+                || OBTAIN_ATTRIBUTES.equals(name)
+                || OBTAIN_TYPED_ARRAY.equals(name)) {
+            if ((owner.equals(CONTEXT_CLS) || owner.equals(RESOURCES_CLS))
+                    && desc.endsWith(TYPED_ARRAY_SIG)) {
+                mObtainsTypedArray = true;
+                if (phase == 2 && !mRecyclesTypedArray) {
+                    context.report(ISSUE, method, call, context.getLocation(call),
+                            getErrorMessage(TYPED_ARRAY_CLS),
+                            null);
+                } else if (phase == 1
+                        && checkMethodFlow(context, classNode, method, call, TYPED_ARRAY_CLS)) {
+                    // Already reported error above; don't do global check
+                    mRecyclesTypedArray = true;
+                }
+            }
+        }
+    }
+
+    /** Computes an error message for a missing recycle of the given type */
+    private static String getErrorMessage(String owner) {
+        String className = owner.substring(owner.lastIndexOf('/') + 1);
+        return String.format("This %1$s should be recycled after use with #recycle()",
+                className);
+    }
+
+    /**
+     * Ensures that the given allocate call in the given method has a
+     * corresponding recycle method, also within the same method, OR, the
+     * allocated resource flows out of the method (either as a return value, or
+     * into a field, or into some other method (with some known exceptions; e.g.
+     * passing a MotionEvent into another MotionEvent's constructor is fine)
+     * <p>
+     * Returns true if an error was found
+     */
+    private static boolean checkMethodFlow(ClassContext context, ClassNode classNode,
+            MethodNode method, MethodInsnNode call, String recycleOwner) {
+        RecycleTracker interpreter = new RecycleTracker(context, method, call, recycleOwner);
+        ResourceAnalyzer analyzer = new ResourceAnalyzer(interpreter);
+        interpreter.setAnalyzer(analyzer);
+        try {
+            analyzer.analyze(classNode.name, method);
+            if (!interpreter.isRecycled() && !interpreter.isEscaped()) {
+                Location location = context.getLocation(call);
+                String message = getErrorMessage(recycleOwner);
+                context.report(ISSUE, method, call, location, message, null);
+                return true;
+            }
+        } catch (AnalyzerException e) {
+            context.log(e, null);
+        }
+
+        return false;
+    }
+
+    /**
+     * ASM interpreter which tracks the instances of the allocated resource, and
+     * checks whether it is eventually passed to a {@code recycle()} call. If the
+     * value flows out of the method (to a field, or a method call), it will
+     * also consider the resource recycled.
+     */
+    private static class RecycleTracker extends Interpreter {
+        private final Value INSTANCE = BasicValue.INT_VALUE; // Only identity matters, not value
+        private final Value RECYCLED = BasicValue.FLOAT_VALUE;
+        private final Value UNKNOWN = BasicValue.UNINITIALIZED_VALUE;
+
+        private final ClassContext mContext;
+        private final MethodNode mMethod;
+        private final MethodInsnNode mObtainNode;
+        private boolean mIsRecycled;
+        private boolean mEscapes;
+        private final String mRecycleOwner;
+        private ResourceAnalyzer mAnalyzer;
+
+        public RecycleTracker(
+                @NonNull ClassContext context,
+                @NonNull MethodNode method,
+                @NonNull MethodInsnNode obtainNode,
+                @NonNull String recycleOwner) {
+            super(Opcodes.ASM4);
+            mContext = context;
+            mMethod = method;
+            mObtainNode = obtainNode;
+            mRecycleOwner = recycleOwner;
+        }
+
+        /**
+         * Sets the analyzer associated with the interpreter, such that it can
+         * get access to the execution frames
+         */
+        void setAnalyzer(ResourceAnalyzer analyzer) {
+            mAnalyzer = analyzer;
+        }
+
+        /**
+         * Returns whether a recycle call was found for the given method
+         *
+         * @return true if the resource was recycled
+         */
+        public boolean isRecycled() {
+            return mIsRecycled;
+        }
+
+        /**
+         * Returns whether the target resource escapes from the method, for
+         * example as a return value, or a field assignment, or getting passed
+         * to another method
+         *
+         * @return true if the resource escapes
+         */
+        public boolean isEscaped() {
+            return mEscapes;
+        }
+
+        @Override
+        public Value newOperation(AbstractInsnNode node) throws AnalyzerException {
+            return UNKNOWN;
+        }
+
+        @Override
+        public Value newValue(final Type type) {
+            if (type != null && type.getSort() == Type.VOID) {
+                return null;
+            } else {
+                return UNKNOWN;
+            }
+        }
+
+        @Override
+        public Value copyOperation(AbstractInsnNode node, Value value) throws AnalyzerException {
+            return value;
+        }
+
+        @Override
+        public Value binaryOperation(AbstractInsnNode node, Value value1, Value value2)
+                throws AnalyzerException {
+            if (node.getOpcode() == Opcodes.PUTFIELD) {
+                if (value2 == INSTANCE) {
+                    mEscapes = true;
+                }
+            }
+            return merge(value1, value2);
+        }
+
+        @Override
+        public Value naryOperation(AbstractInsnNode node, List values) throws AnalyzerException {
+            if (node == mObtainNode) {
+                return INSTANCE;
+            }
+
+            MethodInsnNode call = null;
+            if (node.getType() == AbstractInsnNode.METHOD_INSN) {
+                call = (MethodInsnNode) node;
+                if (node.getOpcode() == Opcodes.INVOKEVIRTUAL) {
+                    if (call.name.equals(RECYCLE) && call.owner.equals(mRecycleOwner)) {
+                        if (values != null && values.size() == 1 && values.get(0) == INSTANCE) {
+                            mIsRecycled = true;
+                            Frame frame = mAnalyzer.getCurrentFrame();
+                            if (frame != null) {
+                                int localSize = frame.getLocals();
+                                for (int i = 0; i < localSize; i++) {
+                                    Value local = frame.getLocal(i);
+                                    if (local == INSTANCE) {
+                                        frame.setLocal(i, RECYCLED);
+                                    }
+                                }
+                                int stackSize = frame.getStackSize();
+                                if (stackSize == 1 && frame.getStack(0) == INSTANCE) {
+                                    frame.pop();
+                                    frame.push(RECYCLED);
+                                }
+                            }
+                            return RECYCLED;
+                        }
+                    }
+                }
+            }
+
+            if (values != null && values.size() >= 1) {
+                // Skip the first element: method calls *on* the TypedArray are okay
+                int start = node.getOpcode() == Opcodes.INVOKESTATIC ? 0 : 1;
+                for (int i = 0, n = values.size(); i < n; i++) {
+                    Object v = values.get(i);
+                    if (v == INSTANCE && i >= start) {
+                        // Known special cases
+                        if (node.getOpcode() == Opcodes.INVOKESTATIC) {
+                            assert call != null;
+                            if (call.name.equals(OBTAIN) &&
+                                    call.owner.equals(MOTION_EVENT_CLS)) {
+                                return UNKNOWN;
+                            }
+                        }
+
+                        // Passing the instance to another method: could leak
+                        // the instance out of this method (for example calling
+                        // a method which recycles it on our behalf, or store it
+                        // in some holder which will recycle it later). In this
+                        // case, just assume that things are okay.
+                        mEscapes = true;
+                    } else if (v == RECYCLED && call != null) {
+                        Location location = mContext.getLocation(call);
+                        String message = String.format("This %1$s has already been recycled",
+                                mRecycleOwner.substring(mRecycleOwner.lastIndexOf('/') + 1));
+                        mContext.report(ISSUE, mMethod, call, location, message, null);
+                    }
+                }
+            }
+
+            return UNKNOWN;
+        }
+
+        @Override
+        public Value unaryOperation(AbstractInsnNode node, Value value) throws AnalyzerException {
+            return value;
+        }
+
+        @Override
+        public Value ternaryOperation(AbstractInsnNode node, Value value1, Value value2,
+                Value value3) throws AnalyzerException {
+            if (value1 == RECYCLED || value2 == RECYCLED || value3 == RECYCLED) {
+                return RECYCLED;
+            } else  if (value1 == INSTANCE || value2 == INSTANCE || value3 == INSTANCE) {
+                return INSTANCE;
+            }
+            return UNKNOWN;
+        }
+
+        @Override
+        public void returnOperation(AbstractInsnNode node, Value value1, Value value2)
+                throws AnalyzerException {
+            if (value1 == INSTANCE || value2 == INSTANCE) {
+                mEscapes = true;
+            }
+        }
+
+        @Override
+        public Value merge(Value value1, Value value2) {
+            if (value1 == RECYCLED || value2 == RECYCLED) {
+                return RECYCLED;
+            } else if (value1 == INSTANCE || value2 == INSTANCE) {
+                return INSTANCE;
+            }
+            return UNKNOWN;
+        }
+    }
+
+    private static class ResourceAnalyzer extends Analyzer {
+        private Frame mCurrent;
+        private Frame mFrame1;
+        private Frame mFrame2;
+
+        public ResourceAnalyzer(Interpreter interpreter) {
+            super(interpreter);
+        }
+
+        Frame getCurrentFrame() {
+            return mCurrent;
+        }
+
+        @Override
+        protected void init(String owner, MethodNode m) throws AnalyzerException {
+            mCurrent = mFrame2;
+            super.init(owner, m);
+        }
+
+        @Override
+        protected Frame newFrame(int nLocals, int nStack) {
+            // Stash the two most recent frame allocations. When init is called the second
+            // most recently seen frame is the current frame used during execution, which
+            // is where we need to replace INSTANCE with RECYCLED when the void
+            // recycle method is called.
+            Frame newFrame = super.newFrame(nLocals, nStack);
+            mFrame2 = mFrame1;
+            mFrame1 = newFrame;
+            return newFrame;
+        }
+    }
+}