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14 Commits

Author SHA1 Message Date
Elias Naur
ab9391cb88 bind: handle ClassNotFoundExceptions on older Androids
If a wrapped Java class is missing at runtime, for example because
the app is running on an older Android version, the resulting class
not found exception would cause the app to crash. Fix it by ignoring
missing classes, allowing the app to avoid using them according to a
runtime version check.

Change-Id: I9138c4e2a905b180959306ecbb997695236ab273
Reviewed-on: https://go-review.googlesource.com/35853
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-31 20:25:05 +00:00
Elias Naur
2f5693b8d8 bind,internal/importers: always generate toString methods
When wrapping Java exceptions, their toString() methods are called from
the wrapper's Error() method to satisfy the Go error interface. Make
sure toString() is always included, even if it never directly referenced
from bound packages.

Change-Id: I5653f6ad82afbe4b061e02a69d60453000288a83
Reviewed-on: https://go-review.googlesource.com/35189
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-17 14:05:11 +00:00
Elias Naur
3884e8cb98 internal,bind: resolve overloaded methods at runtime
Before this CL, calling overloaded methods on reverse bound Java
classes and interfaces involved confusing and ugly name mangling.
If a set of methods with the same name differed only in argument count,
the mangling was simply adding the argument count to the name:

func F()
func F1(int32)

But if two or more methods had the same number of arguments, the type
had to be appended:

func (...) F() int32
func (...) F1(int32) (int32, error)
func (...) F__I(int32, int32)
func (...) F__JLjava_util_concurrent_TimeUnit_2(int64, concurrent.TimeUnit)

This CL sacrifices a bit of type safety and performance to regain the
convenience and simplicity of Go by resolving overloaded method dispatch
at runtime.

Overloaded Java methods are combined to one Go method that, when invoked,
determines the correct Java method variant at runtime.

The signature of the Go method  is compatible with every Java method with
that name. For the example above, the single Go method becomes the most
general

func (...) F(...interface{}) (interface{}, error)

The method is variadic to cover function with a varying number of
arguments, and it returns interface{} to cover int32, int64 and no
argument. Finally, it returns an error to cover the variant that returns
an error. The generator tries to be specific; for example

func G1(int32) int32
func G2(int32, int32) int32

becomes

func G(int32, ...int32) int32

Overriding Java methods in Go is changed to use the Go parameter types to
determine to correct Java method. To avoid name clashes when overriding
multiple overloaded methods, trailing underscores in the method name are
ignored when matching Java methods.  See the Get methods of GoFuture in
bind/testpkg/javapkg for an example.

Change-Id: I6ac3e024141daa8fc2c35187865c5d7a63368094
Reviewed-on: https://go-review.googlesource.com/35186
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-17 14:03:33 +00:00
Elias Naur
1aa9ad5c48 bind: generate reverse functions the same way as methods
This CL restructures function generation to match the way methods
are generated, to avoid two different code paths for a coming CL.

Change-Id: I5a4f15e51ea5df101f9aa419ed4170ab36506418
Reviewed-on: https://go-review.googlesource.com/35185
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-17 14:01:43 +00:00
Elias Naur
c90c4f7c8a bind,internal: change the default Java package to the empty string
The Objective-C bindings was recently changed to support the empty
name prefix and to use that as the default. This CLs changed the Java
generators in the same way, supporting the empty Java package and using
it as the default.

Change-Id: I857affce686c67638a2b6c4e1da5d6a88d7ba560
Reviewed-on: https://go-review.googlesource.com/34778
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-11 19:15:09 +00:00
Elias Naur
fe0977739a bind: generate reverse bindings for implicit Java types
Before this CL, Java types that were only implicitly referenced
were represented as interface{}. However, if a value of such an
implicit type were passed to Java, a runtime crash would occur
because there would be no wrapper class to unwrap.

Fix this by generating implicit types, fixing the crashes,
gaining type safety, and removing the interface{} special case in
the generator.

While we're here, remove a redundant insert to the clsMap map in
java.go.

Change-Id: Ic50125da3d7cd6075899bf628d419b084c630490
Reviewed-on: https://go-review.googlesource.com/34777
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-11 19:09:27 +00:00
Elias Naur
ff6f6e8d8e bind,cmd,internal: generate reverse bindings for exported Go structs
Before this CL, the type of the implicit "this" parameter to Java methods
implemented in Go could only be a super class of the generated Java
class. For example, the following GoRunnable type is an implementation of
the Java interface java.lang.Runnable with a toString method:

package somepkg

import "Java/java/lang"

type GoRunnable struct {
    lang.Runnable
}

func (r *GoRunnable) ToString(this lang.Runnable) string {
    ...
}

The "this" parameter is implicit in the sense that the reverse generator
automatically fills it with a reference to the Java instance of
GoRunnable.

Note that "this" has the type Java/java/lang.Runnable, not
Java/go/somepkg.GoRunnable, which renders it impossible to call Java
methods and functions that expect GoRunnable. The most practical example
of this is the Android databinding libraries.

This CL changes the implicit this parameter to always match the exact
type. In the example, the toString implementation becomes:

import gopkg "Java/go/somepkg"

func (r *GoRunnable) ToString(this gopkg.GoRunnable) string {
    ...
}

One strategy would be to simply treat the generated Java classes
(GoRunnable in our example) as any other Java class and import it
through javap. However, since the Java classes are generated after
importing, this present a chicken-and-egg problem.

Instead, use the newly added support for structs with embedded prefixed types
and synthesize class descriptors for every exported Go struct type.

Change-Id: Ic5ce4a151312bd89f91798ed4088c9959225b448
Reviewed-on: https://go-review.googlesource.com/34776
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-11 19:06:53 +00:00
Elias Naur
fa10d8888b bind: fix inner class argument and return types
Change-Id: I1e74a7475ee3af491605e289685cda001ec80bb6
Reviewed-on: https://go-review.googlesource.com/34647
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-04 17:11:03 +00:00
Elias Naur
e0bb90a948 bind: clear JNI return values when an exception was raised
The return value of a JNI call is undefined when an exception was
raised during the call. To make sure comparisons with NULL works,
clear the value when an exception is raised.

No new tests; some devices, like the Samsung S2, crashes with the
existing tests without this CL.

Change-Id: I85eb983e9444fff1f05e0f83a0640d106280e54d
Reviewed-on: https://go-review.googlesource.com/34631
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2016-12-27 15:54:01 +00:00
Elias Naur
e107ad8ed2 bind: sanitize parameter names
Package names, type names and method names are already sanitized.
Extend that to parameter names as well.

Change-Id: I408024c5e2f9561c37e8059a2b53199ee1afaef6
Reviewed-on: https://go-review.googlesource.com/31519
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-10-21 09:25:03 +00:00
Elias Naur
63993740dd bind: fix field accessors for Go implemented Java classes
The go_seq_to_refnum function handles its argument object as a Java
object if it doesn't implement Seq.Proxy. Java classes implemented in
Go does not implement Seq.Proxy, but when passing "this" references to
Go, instances must be treated as a Go object.

Use go_seq_to_refnum_go everywhere "this" is passed to Go, which fixes
field accessors and simplifies the method call case.

Change-Id: I3d01c63d7b2081e6344ece431f5e5021a9dd7662
Reviewed-on: https://go-review.googlesource.com/31171
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-10-17 10:26:22 +00:00
Elias Naur
89b8360218 bind: remove error wrappers to preserve error instance identity
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>
2016-10-04 09:11:42 +00:00
Elias Naur
2dcaa053a0 bind: preserve no-arg Java constructors
When the Java class parser began culling unused constructors, the
logic for determining whether a given Java class has a no-arg
constructor broke when the no-arg constructor is culled. Add
an explicit field for tracking the no-arg constructor property.

Change-Id: Ib68929ae1108bd6fa1fd23de1d134332eb0d97a2
Reviewed-on: https://go-review.googlesource.com/29875
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2016-09-30 14:00:14 +00:00
Elias Naur
bdf873ed8f bind,cmd: accept Java API in bound packages
Accept Java API interface types as arguments and return values from
bound Go package functions and methods. Also, allow Go structs
to extend Java classes and implement Java interfaces as well as override
and implement methods.

This is the third and final part of the implementation of the golang/go#16876
proposal.

Fixes golang/go#16876

Change-Id: I6951dd87235553ce09abe5117a39a503466163c0
Reviewed-on: https://go-review.googlesource.com/28597
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-09-22 10:16:33 +00:00