Raw JNI arrays (#144)

* Create unsafe _jnicall to simplify error checks

* add JNIArray, returned java arrays w/o conversion

* Basic mutable JNIArray functionality

* Better interface, finalizer, fixes

* add conversion and basic tests

* Add support for short to conventional_name

Co-authored-by: João David <[email protected]>

* replace `isnothing` for backwards compatibility

* Use src/core.jl from master branch

* Rename JNIArray to JNIVector in case Java ever gets builtin nd arrays

Co-authored-by: André Breda <[email protected]>
Co-authored-by: João David <[email protected]>
Co-authored-by: [email protected] <[email protected]>

Author: 4 people

src/JavaCall.jl

@@ -7,7 +7,7 @@ module JavaCall
     Base.Experimental.@optlevel 1
 end
 
-export JavaObject, JavaMetaClass,
+export JavaObject, JavaMetaClass, JNIVector,
        jint, jlong, jbyte, jboolean, jchar, jshort, jfloat, jdouble, jvoid,
        JObject, JClass, JMethod, JConstructor, JField, JString,
        JavaRef, JavaLocalRef, JavaGlobalRef, JavaNullRef,
@@ -39,6 +39,7 @@ include("jvm.jl")
 include("core.jl")
 include("convert.jl")
 include("reflect.jl")
+include("jniarray.jl")
 
 Base.@deprecate_binding jnifunc JavaCall.JNI.jniref[]
 

src/jniarray.jl

@@ -0,0 +1,77 @@
+jniname(::Type{jboolean}) = "Boolean"
+jniname(::Type{jbyte}) = "Byte"
+jniname(::Type{jchar}) = "Char"
+jniname(::Type{jshort}) = "Short"
+jniname(::Type{jint}) = "Int"
+jniname(::Type{jlong}) = "Long"
+jniname(::Type{jfloat}) = "Float"
+jniname(::Type{jdouble}) = "Double"
+
+
+mutable struct JNIVector{T} <: AbstractVector{T}
+    ref::JavaRef
+    arr::Union{Nothing,Vector{T}}
+    function JNIVector{T}(ref) where T
+        j = new{T}(ref, nothing)
+        finalizer(deleteref, j)
+        return j
+    end
+end
+
+Base.getindex(jarr::JNIVector, args...) = getindex(jarr.arr, args...)
+Base.setindex!(jarr::JNIVector, args...) = setindex!(jarr.arr, args...)
+Base.size(jarr::JNIVector, args...; kwargs...) = size(jarr.arr, args...; kwargs...)
+
+function deleteref(x::JNIVector{T}) where T
+    if x.arr !== nothing
+        release_elements(x)
+    end
+    deleteref(x.ref)
+    x.ref = J_NULL
+end
+
+signature(::Type{JNIVector{T}}) where T = string("[", signature(T))
+jvalue(jarr::JNIVector) = jarr.ref.ptr
+JNIVector{T}(ptr::Ptr{Nothing}) where {T} = JNIVector{T}(JavaLocalRef(ptr))
+
+function convert(::Type{JNIVector{T}}, vec::Vector{T}) where {T}
+    arr = JNIVector{T}(length(vec))
+    arr .= vec
+    return arr
+end
+
+JNIVector(vec::Vector{T}) where {T} = convert(JNIVector{T}, vec)
+
+for primitive in [:jboolean, :jchar, :jbyte, :jshort, :jint, :jlong, :jfloat, :jdouble]
+    name = jniname(eval(primitive))
+    get_elements = :(JNI.$(Symbol("Get$(name)ArrayElements")))
+    release_elements = :(JNI.$(Symbol("Release$(name)ArrayElements")))
+    new_array = :(JNI.$(Symbol("New$(name)Array")))
+    m = quote
+        function get_elements!(jarr::JNIVector{$primitive})
+            sz = Int(JNI.GetArrayLength(jarr.ref.ptr))
+            jarr.arr = unsafe_wrap(Array, $get_elements(jarr.ref.ptr, Ptr{jboolean}(C_NULL)), sz)
+            jarr
+        end
+        JNIVector{$primitive}(sz::Int) = get_elements!(JNIVector{$primitive}($new_array(sz)))
+        function release_elements(arg::JNIVector{$primitive})
+            $release_elements(arg.ref.ptr, pointer(arg.arr), jint(0))
+            arg.arr = nothing
+        end
+        function convert_result(::Type{JNIVector{$primitive}}, ptr)
+            get_elements!(JNIVector{$primitive}(ptr))
+        end
+        function convert_arg(argtype::Type{Vector{$primitive}}, arg::JNIVector{$primitive})
+            release_elements(arg)
+            return arg, arg
+        end
+        function convert_arg(argtype::Type{JNIVector{$primitive}}, arg::JNIVector{$primitive})
+            release_elements(arg)
+            return arg, arg
+        end
+        function cleanup_arg(jarr::JNIVector{$primitive})
+            get_elements!(jarr)
+        end
+    end
+    eval(m)
+end

test/runtests.jl

@@ -226,6 +226,27 @@ end
     @test size(jcall(T, "testStringArray2D", Array{JString,2}, ())) == (2,2)
 end
 
+@testset "jni_arrays_1" begin
+    j_u_arrays = @jimport java.util.Arrays
+    arr = jint[10,20,30,40,50,60]
+    jniarr = JNIVector(arr)
+    @test length(arr) == length(jniarr)
+    @test size(arr) == size(jniarr)
+    @test all(arr .== jniarr)
+    @test 3 == jcall(j_u_arrays, "binarySearch", jint, (JNIVector{jint}, jint), jniarr, 40)
+    @test "[10, 20, 30, 40, 50, 60]" == jcall(j_u_arrays, "toString", JString, (JavaCall.JNIVector{jint},), jniarr)
+
+    JCharBuffer = @jimport(java.nio.CharBuffer)
+    buf = jcall(JCharBuffer, "wrap", JCharBuffer, (JNIVector{jchar},), JNIVector(jchar.(collect("array"))))
+    @test "array" == jcall(buf, "toString", JString, ())
+
+    # Ensure JNIVectors are garbage collected properly
+    for i in 1:100000
+        a = JNIVector(jchar[j == i ? 0 : 1 for j in 1:10000])
+        buf = jcall(JCharBuffer, "wrap", JCharBuffer, (JNIVector{jchar},), a)
+    end
+end
+
 @testset "dates_1" begin
     jd = @jimport(java.util.Date)(())
     jcal = @jimport(java.util.GregorianCalendar)(())