Commit 951f99ba authored May 15, 2019 by Jeff Sharkey

Cache resolved details about remote callers.

The logic in MediaProvider is technically correct, but it's sometimes
inefficient in calling into the OS multiple times with the same
questions, such as validating getCallingPackage().

To mitigate this overhead, and start paving the way for more dynamic
delegation of permission checks, collect these details into a
LocalCallingIdentity object.  We carefully perform all permissions
checking against this new object, and avoid using any other
thread-local values from ContentProvider or Binder.

Local tests show this CL improves performance of a test app that
takes 100 rapid shots by 37%.

This change is a no-op refactoring.

Bug: 130758409, 115619667
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: If250a7675f2246cd10881acf615619d6d6061f3d

parent cfaa8ead

core/java/android/content/ContentProvider.java

+10 −0

Original line number	Diff line number	Diff line
		@@ -820,6 +820,7 @@ public abstract class ContentProvider implements ContentInterface, ComponentCall
		private String setCallingPackage(String callingPackage) {
		final String original = mCallingPackage.get();
		mCallingPackage.set(callingPackage);
		onCallingPackageChanged();
		return original;
		}

		@@ -845,6 +846,15 @@ public abstract class ContentProvider implements ContentInterface, ComponentCall
		return pkg;
		}

		/** {@hide} */
		public final @Nullable String getCallingPackageUnchecked() {
		return mCallingPackage.get();
		}

		/** {@hide} */
		public void onCallingPackageChanged() {
		}

		/**
		* Opaque token representing the identity of an incoming IPC.
		*/