CL 24800 changed the error representation from strings to objects.
However, since native errors types are not immediately compatible
across languages, wrapper types were introduced to bridge the gap.
This CL remove those wrappers and instead special case the error
proxy types to conform to their language error protocol.
Specifically:
- The ObjC proxy for Go errors now extends NSError and calls
initWithDomain to store the error message.
- The Go proxy for ObjC NSError return the localizedDescription
property for calls to Error.
- The Java proxy for Go errors ow extends Exception and
overrides getMessage() to return the error message.
- The Go proxy for Java Exceptions returns getMessage whenever
Error is called.
The end result is that error values behave more like normal objects
across the language boundary. In particular, instance identity is
now preserved: an error passed across the boundary and back will
result in the same instance.
There are two semantic changes that followed this change:
- The domain for wrapped Go errors is now always "go".
The domain wasn't useful before this CL: the domains were set to
the package name of function or method where the error happened
to cross the language boundary.
- If a Go method that returns an error is implemented in ObjC, the
implementation must now both return NO _and_ set the error result
for the calling Go code to receive a non-nil error.
Before this CL, because errors were always wrapped, a nil ObjC
could be represented with a non-nil wrapper.
Change-Id: Idb415b6b13ecf79ccceb60f675059942bfc48fec
Reviewed-on: https://go-review.googlesource.com/29298
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Gobind uses strings for passing errors across the language barrier.
However, since Gobind doesn't have a concept of a nil string, it
can't separate an empty native string from a nil string.
In turn, that means that empty errors, exceptions or NSError * with
an empty description are treated as no error. With ObjC, empty errors
are replaced with a default string to workaround the issue, while
with Java empty errors are silently ignored.
Fix this by replacing strings with actual error objects, wrapping
the Go error, Java Throwable or ObjC NSError *, and letting the
existing bind machinery take care of passing the references across.
It's a large change for a small corner case, but I believe objects
are a better fit for exception that strings. Error objects also
naturally leads to future additions, for example accessing the
exception class name or chained exception.
Change-Id: Ie03b47cafcb231ad1e12a80195693fa7459c6265
Reviewed-on: https://go-review.googlesource.com/24100
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Each side of the language barrier maintains a map of reference numbers
to objects. Each entry has a reference count that exactly matches
the number of active proxy objects on the other side. When a reference
crosses the barrier, the count is incremented and when a proxy finalizer
is run, the count is decremented. If the count reaches 0, the reference
number and its object are removed from the map.
There is a possibility that a reference number is passed to the other
side, and the last proxy is then immediately garbage collected and
finalized. The reference counter then reaches 0 before the other side has
converted the reference number to its object, crashing the program.
This is possible in both Go/Java/ObjC but is most likely to happen in
ObjC because its own automatic reference count runtime frees objects
as soon as they are statically never referenced again.
Fix the race by always incrementing the reference count before sending
a reference across the barrier. When converting the reference back into
an object on the other side, decrement the counter again.
Only the new ObjC test fails without this fix, but I left the Java
counterpart in for good measure.
Change-Id: I92743aabec275b4a5b82b952052e7e284872ce02
Reviewed-on: https://go-review.googlesource.com/21311
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
The objc reference handling has bug on assigning different refnum
to the same ios object. The reason for this is that the
RefTracker _refs is not properly initialized thus incorrect
reference check in assignRefnumAndIncRefcount.
Change-Id: Id86423dcf378d11e9056bf7c7ecb646333a94a04
Reviewed-on: https://go-review.googlesource.com/21120
Reviewed-by: Elias Naur <elias.naur@gmail.com>
An extra struct initializer was left over from an earlier version
of the direct call conversion. Remove it.
Change-Id: I19c3eb3be7bf78378af47ea182931b0c24cdd34d
Reviewed-on: https://go-review.googlesource.com/21104
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Replace test.bash with go test that builds and run the bind tests
through the XCode testing framework.
Running on the iOS emulator unmasked a bug where autorelease pools
were not in place for Go calls into ObjC, leaking autoreleased
objects. Fix that by adding autoreleasepool blocks to the tracker
finalizer callback and to every generated ObjC proxy.
Will not run on the emulator without CL 19206.
Change-Id: I6a775f9995f3b8ea50272982069d033e41ddcb7b
Reviewed-on: https://go-review.googlesource.com/20255
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
LOG_FATAL already throws an exception on iOS. Make it abort() on
Android, so that any fatal error will hopefully end up with a useful
log instead of an easily missed message in logcat.
Also, remove return statements after LOG_FATAL on both platforms.
They're unnecessary and confusing and they weren't used consistently
anyway.
Change-Id: I2a8e2e0ac064e95f52ca130de17265c9741cefe4
Reviewed-on: https://go-review.googlesource.com/20257
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
The seq serialization machinery is a historic artifact from when Go
mobile code had to run in a separate process. Now that Go code is running
in-process, replace the explicit serialization with direct calls and pass
arguments on the stack.
The benefits are a much smaller bind runtime, much less garbage (and, in
Java, fewer objects with finalizers), less argument copying, and faster
cross-language calls.
The cost is a more complex generator, because some of the work from the
bind runtime is moved to generated code. Generated code now handles
conversion between Go and Java/ObjC types, multiple return values and memory
management of byte slice and string arguments.
To overcome the lack of calling C code between Go packages, all bound
packages now end up in the same (fake) package, "gomobile_bind", instead of
separate packages (go_<pkgname>). To avoid name clashes, the package name is
added as a prefix to generated functions and types.
Also, don't copy byte arrays passed to Go, saving call time and
allowing read([]byte)-style interfaces to foreign callers (#12113).
Finally, add support for nil interfaces and struct pointers to objc.
This is a large CL, but most of the changes stem from changing testdata.
The full benchcmp output on the CL/20095 benchmarks on my Nexus 5 is
reproduced below. Note that the savings for the JavaSlice* benchmarks are
skewed because byte slices are no longer copied before passing them to Go.
benchmark old ns/op new ns/op delta
BenchmarkJavaEmpty 26.0 19.0 -26.92%
BenchmarkJavaEmptyDirect 23.0 22.0 -4.35%
BenchmarkJavaNoargs 7685 2339 -69.56%
BenchmarkJavaNoargsDirect 17405 8041 -53.80%
BenchmarkJavaOnearg 26887 2366 -91.20%
BenchmarkJavaOneargDirect 34266 7910 -76.92%
BenchmarkJavaOneret 38325 2245 -94.14%
BenchmarkJavaOneretDirect 46265 7708 -83.34%
BenchmarkJavaManyargs 41720 2535 -93.92%
BenchmarkJavaManyargsDirect 51026 8373 -83.59%
BenchmarkJavaRefjava 38139 21260 -44.26%
BenchmarkJavaRefjavaDirect 42706 28150 -34.08%
BenchmarkJavaRefgo 34403 6843 -80.11%
BenchmarkJavaRefgoDirect 40193 16582 -58.74%
BenchmarkJavaStringShort 32366 9323 -71.20%
BenchmarkJavaStringShortDirect 41973 19118 -54.45%
BenchmarkJavaStringLong 127879 94420 -26.16%
BenchmarkJavaStringLongDirect 133776 114760 -14.21%
BenchmarkJavaStringShortUnicode 32562 9221 -71.68%
BenchmarkJavaStringShortUnicodeDirect 41464 19094 -53.95%
BenchmarkJavaStringLongUnicode 131015 89401 -31.76%
BenchmarkJavaStringLongUnicodeDirect 134130 90786 -32.31%
BenchmarkJavaSliceShort 42462 7538 -82.25%
BenchmarkJavaSliceShortDirect 52940 17017 -67.86%
BenchmarkJavaSliceLong 138391 8466 -93.88%
BenchmarkJavaSliceLongDirect 205804 15666 -92.39%
BenchmarkGoEmpty 3.00 3.00 +0.00%
BenchmarkGoEmptyDirect 3.00 3.00 +0.00%
BenchmarkGoNoarg 40342 13716 -66.00%
BenchmarkGoNoargDirect 46691 13569 -70.94%
BenchmarkGoOnearg 43529 13757 -68.40%
BenchmarkGoOneargDirect 44867 14078 -68.62%
BenchmarkGoOneret 45456 13559 -70.17%
BenchmarkGoOneretDirect 44694 13442 -69.92%
BenchmarkGoRefjava 55111 28071 -49.06%
BenchmarkGoRefjavaDirect 60883 26872 -55.86%
BenchmarkGoRefgo 57038 29223 -48.77%
BenchmarkGoRefgoDirect 56153 27812 -50.47%
BenchmarkGoManyargs 67967 17398 -74.40%
BenchmarkGoManyargsDirect 60617 16998 -71.96%
BenchmarkGoStringShort 57538 22600 -60.72%
BenchmarkGoStringShortDirect 52627 22704 -56.86%
BenchmarkGoStringLong 128485 52530 -59.12%
BenchmarkGoStringLongDirect 138377 52079 -62.36%
BenchmarkGoStringShortUnicode 57062 22994 -59.70%
BenchmarkGoStringShortUnicodeDirect 62563 22938 -63.34%
BenchmarkGoStringLongUnicode 139913 55553 -60.29%
BenchmarkGoStringLongUnicodeDirect 150863 57791 -61.69%
BenchmarkGoSliceShort 59279 20215 -65.90%
BenchmarkGoSliceShortDirect 60160 21136 -64.87%
BenchmarkGoSliceLong 411225 301870 -26.59%
BenchmarkGoSliceLongDirect 399029 298915 -25.09%
Fixesgolang/go#12619Fixesgolang/go#12113Fixesgolang/go#13033
Change-Id: I2b45e9e98a1248e3c23a5137f775f7364908bec7
Reviewed-on: https://go-review.googlesource.com/19821
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
