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add ObjC.ProxyBlock, #45

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add ObjC.ProxyBlock, #45

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175 changes: 127 additions & 48 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ function Runtime() {
let cachedNSNumber = null;
let cachedNSNumberCtor = null;
let singularTypeById = null;
const proxyBlocks = new Map();

try {
tryInitialize();
Expand Down Expand Up @@ -98,6 +99,11 @@ function Runtime() {
value: Block
});

Object.defineProperty(this, 'ProxyBlock', {
enumerable: true,
value: ProxyBlock
});

Object.defineProperty(this, 'mainQueue', {
enumerable: true,
get() {
Expand Down Expand Up @@ -1251,16 +1257,19 @@ function Runtime() {
return "ObjCIvars";
}
}

let blockDescriptorAllocSize, blockDescriptorDeclaredSize, blockDescriptorOffsets;

// remove blockDescriptorDeclaredSize because Descriptor use blockSize;
let blockDescriptorAllocSize, blockDescriptorOffsets;
let blockSize, blockOffsets;
if (pointerSize === 4) {
blockDescriptorAllocSize = 16; /* sizeof (BlockDescriptor) == 12 */
blockDescriptorDeclaredSize = 20;
blockDescriptorAllocSize = 20;
blockDescriptorOffsets = {
reserved: 0,
size: 4,
rest: 8
rest: 8,
copy: 8,
dispose: 12,
signature: 16
};

blockSize = 20;
Expand All @@ -1272,12 +1281,14 @@ function Runtime() {
descriptor: 16
};
} else {
blockDescriptorAllocSize = 32; /* sizeof (BlockDescriptor) == 24 */
blockDescriptorDeclaredSize = 32;
blockDescriptorOffsets = {
blockDescriptorAllocSize = 48;
blockDescriptorOffsets = { /*all 3 parts of descriptor, but keep 'rest' for read block.*/
reserved: 0,
size: 8,
rest: 16
rest: 16,//
copy: 16,
dispose: 24,
signature: 32
};

blockSize = 32;
Expand Down Expand Up @@ -1320,7 +1331,7 @@ function Runtime() {
const typesStr = Memory.allocUtf8String(this.types);

descriptor.add(blockDescriptorOffsets.reserved).writeULong(0);
descriptor.add(blockDescriptorOffsets.size).writeULong(blockDescriptorDeclaredSize);
descriptor.add(blockDescriptorOffsets.size).writeULong(blockSize);//see libclosure/runtime.cpp:_Block_copy stack_block
descriptor.add(blockDescriptorOffsets.rest).writePointer(typesStr);

block.add(blockOffsets.isa).writePointer(classRegistry.__NSGlobalBlock__);
Expand All @@ -1336,48 +1347,116 @@ function Runtime() {
}
}

Object.defineProperties(Block.prototype, {
implementation: {
enumerable: true,
get() {
const address = this.handle.add(blockOffsets.invoke).readPointer().strip();
const signature = this._getSignature();
return makeBlockInvocationWrapper(this, signature, new NativeFunction(
address.sign(),
signature.retType.type,
signature.argTypes.map(function (arg) { return arg.type; }),
this._options));
},
set(func) {
const signature = this._getSignature();
const callback = new NativeCallback(
makeBlockImplementationWrapper(this, signature, func),
signature.retType.type,
signature.argTypes.map(function (arg) { return arg.type; }));
this._callback = callback;
const location = this.handle.add(blockOffsets.invoke);
location.writePointer(callback.strip().sign('ia', location));
}
},
declare: {
value(signature) {
let types = signature.types;
if (types === undefined) {
types = unparseSignature(signature.retType, ['block'].concat(signature.argTypes));
const _Block_copy = new NativeFunction(Module.findExportByName('libsystem_blocks.dylib','_Block_copy'),'pointer',['pointer']);
const _Block_release = new NativeFunction(Module.findExportByName('libsystem_blocks.dylib','_Block_release'),'void',['pointer']);

function emptyCallbcak() { }
function blockDispose(block) {
var descriptor = block.add(blockOffsets.descriptor).readPointer();
var key = descriptor.toString();
if(!proxyBlocks.has(key)){
//console.err("Not found Block.descriptor at: "+descriptor.toString());
}else{
var jsblcok = proxyBlocks.get(key);
proxyBlocks.delete(key);
_Block_release(jsblcok.innerBlock.handle);
}
}
const ncBlockDispose = new NativeCallback(blockDispose, 'void', ['pointer']);
const ncEmptyCallback= new NativeCallback(emptyCallbcak, 'void', []);

function ProxyBlock(target, options = defaultInvocationOptions) {
this._options = options;
if (target instanceof NativePointer) {
//read original block.
const descriptor = target.add(blockOffsets.descriptor).readPointer();
const flags = target.add(blockOffsets.flags).readU32();
if ((flags & BLOCK_HAS_SIGNATURE) !== 0) {
const signatureOffset = ((flags & BLOCK_HAS_COPY_DISPOSE) !== 0) ? 2 : 0;
this.types = descriptor.add(blockDescriptorOffsets.rest + (signatureOffset * pointerSize)).readPointer().readCString();
this._signature = parseSignature(this.types);
} else {
//this.types = "v8@?0";
this._signature = null;
}
this.types = types;
this._signature = parseSignature(types);
//copy(oc) and hold(js) original block
this.innerBlock = new Block(_Block_copy(target));
target = {implementation:emptyCallbcak};
} else {
//for ProxyBlock not have innerblock.
this.declare(target);
}
},
_getSignature: {
value() {
const signature = this._signature;
if (signature === null)
throw new Error('block is missing signature; call declare()');
return signature;
//plan: create a malloc block with use_count(last 2 bytes for block.flags) = 0 // but use_count=0 => never copy or release
//doing: create a 'stack' block, can be normally copy & release
const descriptor = Memory.alloc(blockDescriptorAllocSize + blockSize);
const block = descriptor.add(blockDescriptorAllocSize);
const typesStr = Memory.allocUtf8String(this.types);

descriptor.add(blockDescriptorOffsets.reserved).writeULong(0);
descriptor.add(blockDescriptorOffsets.size).writeULong(blockSize);
var t = descriptor.add(blockDescriptorOffsets.copy);//copy helper, use empty function
t.writePointer(ncEmptyCallback.sign('ia',t));
t = descriptor.add(blockDescriptorOffsets.dispose);//dispose helper, use callback to clean jsblock when oc clean ocblock.
t.writePointer(ncBlockDispose.sign('ia',t));
descriptor.add(blockDescriptorOffsets.signature).writePointer(typesStr);

block.add(blockOffsets.isa).writePointer(classRegistry.__NSStackBlock__);
block.add(blockOffsets.flags).writeU32(BLOCK_HAS_SIGNATURE | BLOCK_HAS_COPY_DISPOSE);
block.add(blockOffsets.reserved).writeU32(0);
block.add(blockOffsets.descriptor).writePointer(descriptor);
this.handle = block;
this._storage = [descriptor, typesStr];
this.implementation = target.implementation;

//keey jsblock. block_copy will move block,but not descriptor(not fully tested)
proxyBlocks.set(descriptor.toString(),block);
}

const blockPrototype = {
implementation: {
enumerable: true,
get() {
const address = this.handle.add(blockOffsets.invoke).readPointer().strip();
const signature = this._getSignature();
return makeBlockInvocationWrapper(this, signature, new NativeFunction(
address.sign(),
signature.retType.type,
signature.argTypes.map(function (arg) { return arg.type; }),
this._options));
},
set(func) {
const signature = this._getSignature();
const callback = new NativeCallback(
makeBlockImplementationWrapper(this, signature, func),
signature.retType.type,
signature.argTypes.map(function (arg) { return arg.type; }));
this._callback = callback;
const location = this.handle.add(blockOffsets.invoke);
location.writePointer(callback.strip().sign('ia', location));
}
},
declare: {
value(signature) {
let types = signature.types;
if (types === undefined) {
types = unparseSignature(signature.retType, ['block'].concat(signature.argTypes));
}
this.types = types;
this._signature = parseSignature(types);
}
},
_getSignature: {
value() {
const signature = this._signature;
if (signature === null)
throw new Error('block is missing signature; call declare()');
return signature;
}
}
}
});

Object.defineProperties(Block.prototype, blockPrototype);
Object.defineProperties(ProxyBlock.prototype, blockPrototype);

function collectProtocols(p, acc) {
acc = acc || {};
Expand Down