d387e79ae1
Recently while investigating some Binder limits, I discovered that we're still sending Strings across Binder as UTF-16, which is very wasteful for two reasons: 1. The majority of data flowing through APIs like PackageManager is already limited to US-ASCII, and by sending UTF-16 we're wasting half of our transactions on null-byte overhead. 2. Internally ART is already "compressing" simple strings by storing them as US-ASCII instead of UTF-16, meaning every time we want to write a simple string to Binder, we're forced to first inflate it to UTF-16. This change first updates Parcel.cpp to accept char* UTF-8 strings, similar to how it accepts char16_t* for UTF-16. It then offers both UTF-8 and UTF-16 variants to Parcel.java via JNI. We also update the String8 handling to behave identical to String16. This change adds benchmarking to show that these new methods are about 50% faster for US-ASCII strings, and about 68% faster for complex strings that reference higher Unicode planes. (So an improvement in both cases!) Bug: 154436100 Test: atest FrameworksCoreTests:ParcelTest Test: make core-libart conscrypt okhttp bouncycastle vogar caliper && vogar --mode app_process --benchmark frameworks/base/core/tests/benchmarks/src/android/os/ParcelStringBenchmark.java Change-Id: I22a11d3497486d922ec8e14c85df66ca096b8f2a