From 6c14d7739ac2b177035aa084060aaccdaa7a8ba7 Mon Sep 17 00:00:00 2001
From: zachh <zachh@google.com>
Date: Wed, 9 Aug 2017 17:00:19 -0700
Subject: Some improvements to DialerStrictMode.

Only mutate the thread policy when on the main thread to prevent accidentally changing the policy for a non-main thread. The alternative here is Assert.isMainThread(), but that would make DialerStrictMode more difficult to use.

Also switched one use of #disableDeathPenalty to the more concise #bypass.

Bug: 64118795
Test: verified bugfood build does not crash on launch
PiperOrigin-RevId: 164794473
Change-Id: I58db414cbb003241a1afcddabfd6557612351598
---
 .../dialer/strictmode/DialerStrictMode.java        | 27 +++++++++++++++-------
 1 file changed, 19 insertions(+), 8 deletions(-)

(limited to 'java/com/android/dialer')

diff --git a/java/com/android/dialer/strictmode/DialerStrictMode.java b/java/com/android/dialer/strictmode/DialerStrictMode.java
index c9bbeafbf..3c31aa954 100644
--- a/java/com/android/dialer/strictmode/DialerStrictMode.java
+++ b/java/com/android/dialer/strictmode/DialerStrictMode.java
@@ -16,16 +16,13 @@
 
 package com.android.dialer.strictmode;
 
+import android.os.Looper;
 import android.os.StrictMode;
 import android.os.StrictMode.ThreadPolicy;
 import android.os.StrictMode.VmPolicy;
 import com.android.dialer.buildtype.BuildType;
 
-/**
- * Enables strict mode for the application, and provides means of temporarily disabling it.
- *
- * <p>NOTE: All methods in this class are stripped by proguard in release builds.
- */
+/** Enables strict mode for the application, and provides means of temporarily disabling it. */
 public final class DialerStrictMode {
 
   /** Initializes strict mode on application start. */
@@ -39,10 +36,14 @@ public final class DialerStrictMode {
    *
    * <p>You should typically do this only temporarily and restore the death penalty in a finally
    * block using {@link #enableDeathPenalty()}.
+   *
+   * <p>The thread policy is only mutated if this is called from the main thread.
    */
   public static void disableDeathPenalty() {
     if (isStrictModeAllowed()) {
-      StrictMode.setThreadPolicy(threadPolicyTemplate().build());
+      if (onMainThread()) {
+        StrictMode.setThreadPolicy(threadPolicyTemplate().build());
+      }
       StrictMode.setVmPolicy(vmPolicyTemplate().build());
     }
   }
@@ -50,10 +51,14 @@ public final class DialerStrictMode {
   /**
    * Restore the death penalty. This should typically be called in a finally block after calling
    * {@link #disableDeathPenalty()}.
+   *
+   * <p>The thread policy is only mutated if this is called from the main thread.
    */
   public static void enableDeathPenalty() {
     if (isStrictModeAllowed()) {
-      StrictMode.setThreadPolicy(threadPolicyTemplate().penaltyDeath().build());
+      if (onMainThread()) {
+        StrictMode.setThreadPolicy(threadPolicyTemplate().penaltyDeath().build());
+      }
       StrictMode.setVmPolicy(vmPolicyTemplate().penaltyDeath().build());
     }
   }
@@ -70,6 +75,10 @@ public final class DialerStrictMode {
     return BuildType.get() == BuildType.BUGFOOD;
   }
 
+  private static boolean onMainThread() {
+    return Looper.getMainLooper().equals(Looper.myLooper());
+  }
+
   /** Functional interface intended to be used with {@link #bypass(Provider)}. */
   public interface Provider<T> {
     T get();
@@ -81,8 +90,10 @@ public final class DialerStrictMode {
    * <p>For example:
    *
    * <p><code>
-   *   DialerStrictMode.bypass(() -> doDiskAccessOnMainThread());
+   *   Value foo = DialerStrictMode.bypass(() -> doDiskAccessOnMainThreadReturningValue());
    * </code>
+   *
+   * <p>The thread policy is only mutated if this is called from the main thread.
    */
   public static <T> T bypass(Provider<T> provider) {
     disableDeathPenalty();
-- 
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