You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

308 lines
8.6 KiB

// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// A simple membrane. Adapted from:
// http://wiki.ecmascript.org/doku.php?id=harmony:proxies#a_simple_membrane
function createSimpleMembrane(target) {
let enabled = true;
function wrap(obj) {
if (obj !== Object(obj)) return obj;
let handler = new Proxy({}, {get: function(_, key) {
if (!enabled) throw new Error("disabled");
switch (key) {
case "apply":
return (_, that, args) => {
try {
return wrap(Reflect.apply(
obj, wrap(that), args.map((x) => wrap(x))));
} catch(e) {
throw wrap(e);
}
}
case "construct":
return (_, args, newt) => {
try {
return wrap(Reflect.construct(
obj, args.map((x) => wrap(x)), wrap(newt)));
} catch(e) {
throw wrap(e);
}
}
default:
return (_, ...args) => {
try {
return wrap(Reflect[key](obj, ...(args.map(wrap))));
} catch(e) {
throw wrap(e);
}
}
}
}});
return new Proxy(obj, handler);
}
const gate = Object.freeze({
enable: () => enabled = true,
disable: () => enabled = false
});
return Object.freeze({
wrapper: wrap(target),
gate: gate
});
}
// Test the simple membrane.
{
var o = {
a: 6,
b: {bb: 8},
f: function(x) { return x },
g: function(x) { return x.a },
h: function(x) { this.q = x }
};
o[2] = {c: 7};
var m = createSimpleMembrane(o);
var w = m.wrapper;
var f = w.f;
var x = f(66);
var x = f({a: 1});
var x = w.f({a: 1});
var a = x.a;
assertEquals(6, w.a);
assertEquals(8, w.b.bb);
assertEquals(7, w[2]["c"]);
assertEquals(undefined, w.c);
assertEquals(1, w.f(1));
assertEquals(1, w.f({a: 1}).a);
assertEquals(2, w.g({a: 2}));
assertEquals(3, (w.r = {a: 3}).a);
assertEquals(3, w.r.a);
assertEquals(3, o.r.a);
w.h(3);
assertEquals(3, w.q);
assertEquals(3, o.q);
assertEquals(4, (new w.h(4)).q);
var wb = w.b;
var wr = w.r;
var wf = w.f;
var wf3 = w.f(3);
var wfx = w.f({a: 6});
var wgx = w.g({a: {aa: 7}});
var wh4 = new w.h(4);
m.gate.disable();
assertEquals(3, wf3);
assertThrows(function() { w.a }, Error);
assertThrows(function() { w.r }, Error);
assertThrows(function() { w.r = {a: 4} }, Error);
assertThrows(function() { o.r.a }, Error);
assertEquals("object", typeof o.r);
assertEquals(5, (o.r = {a: 5}).a);
assertEquals(5, o.r.a);
assertThrows(function() { w[1] }, Error);
assertThrows(function() { w.c }, Error);
assertThrows(function() { wb.bb }, Error);
assertThrows(function() { wr.a }, Error);
assertThrows(function() { wf(4) }, Error);
assertThrows(function() { wfx.a }, Error);
assertThrows(function() { wgx.aa }, Error);
assertThrows(function() { wh4.q }, Error);
m.gate.enable();
assertEquals(6, w.a);
assertEquals(5, w.r.a);
assertEquals(5, o.r.a);
assertEquals(7, w.r = 7);
assertEquals(7, w.r);
assertEquals(7, o.r);
assertEquals(8, w.b.bb);
assertEquals(7, w[2]["c"]);
assertEquals(undefined, w.c);
assertEquals(8, wb.bb);
assertEquals(3, wr.a);
assertEquals(4, wf(4));
assertEquals(3, wf3);
assertEquals(6, wfx.a);
assertEquals(7, wgx.aa);
assertEquals(4, wh4.q);
}
// An identity-preserving membrane. Adapted from:
// http://wiki.ecmascript.org/doku.php?id=harmony:proxies#an_identity-preserving_membrane
function createMembrane(target) {
const wet2dry = 0;
const dry2wet = 1;
function flip(dir) { return (dir + 1) % 2 }
let maps = [new WeakMap(), new WeakMap()];
let revoked = false;
function wrap(dir, obj) {
if (obj !== Object(obj)) return obj;
let wrapper = maps[dir].get(obj);
if (wrapper) return wrapper;
let handler = new Proxy({}, {get: function(_, key) {
if (revoked) throw new Error("revoked");
switch (key) {
case "apply":
return (_, that, args) => {
try {
return wrap(dir, Reflect.apply(
obj, wrap(flip(dir), that),
args.map((x) => wrap(flip(dir), x))));
} catch(e) {
throw wrap(dir, e);
}
}
case "construct":
return (_, args, newt) => {
try {
return wrap(dir, Reflect.construct(
obj, args.map((x) => wrap(flip(dir), x)),
wrap(flip(dir), newt)));
} catch(e) {
throw wrap(dir, e);
}
}
default:
return (_, ...args) => {
try {
return wrap(dir, Reflect[key](
obj, ...(args.map((x) => wrap(flip(dir), x)))))
} catch(e) {
throw wrap(dir, e);
}
}
}
}});
wrapper = new Proxy(obj, handler);
maps[dir].set(obj, wrapper);
maps[flip(dir)].set(wrapper, obj);
return wrapper;
}
const gate = Object.freeze({
revoke: () => revoked = true
});
return Object.freeze({
wrapper: wrap(wet2dry, target),
gate: gate
});
}
// Test the identity-preserving membrane.
{
var receiver
var argument
var o = {
a: 6,
b: {bb: 8},
f: function(x) {receiver = this; argument = x; return x},
g: function(x) {receiver = this; argument = x; return x.a},
h: function(x) {receiver = this; argument = x; this.q = x},
s: function(x) {receiver = this; argument = x; this.x = {y: x}; return this}
}
o[2] = {c: 7}
var m = createMembrane(o)
var w = m.wrapper
var f = w.f
var x = f(66)
var x = f({a: 1})
var x = w.f({a: 1})
var a = x.a
assertEquals(6, w.a)
assertEquals(8, w.b.bb)
assertEquals(7, w[2]["c"])
assertEquals(undefined, w.c)
assertEquals(1, w.f(1))
assertSame(o, receiver)
assertEquals(1, w.f({a: 1}).a)
assertSame(o, receiver)
assertEquals(2, w.g({a: 2}))
assertSame(o, receiver)
assertSame(w, w.f(w))
assertSame(o, receiver)
assertSame(o, argument)
assertSame(o, w.f(o))
assertSame(o, receiver)
// Note that argument !== o, since o isn't dry, so gets wrapped wet again.
assertEquals(3, (w.r = {a: 3}).a)
assertEquals(3, w.r.a)
assertEquals(3, o.r.a)
w.h(3)
assertEquals(3, w.q)
assertEquals(3, o.q)
assertEquals(4, (new w.h(4)).q)
assertEquals(5, w.s(5).x.y)
assertSame(o, receiver)
var wb = w.b
var wr = w.r
var wf = w.f
var wf3 = w.f(3)
var wfx = w.f({a: 6})
var wgx = w.g({a: {aa: 7}})
var wh4 = new w.h(4)
var ws5 = w.s(5)
var ws5x = ws5.x
m.gate.revoke()
assertEquals(3, wf3)
assertThrows(function() { w.a }, Error)
assertThrows(function() { w.r }, Error)
assertThrows(function() { w.r = {a: 4} }, Error)
assertThrows(function() { o.r.a }, Error)
assertEquals("object", typeof o.r)
assertEquals(5, (o.r = {a: 5}).a)
assertEquals(5, o.r.a)
assertThrows(function() { w[1] }, Error)
assertThrows(function() { w.c }, Error)
assertThrows(function() { wb.bb }, Error)
assertEquals(3, wr.a)
assertThrows(function() { wf(4) }, Error)
assertEquals(6, wfx.a)
assertEquals(7, wgx.aa)
assertThrows(function() { wh4.q }, Error)
assertThrows(function() { ws5.x }, Error)
assertThrows(function() { ws5x.y }, Error)
}