Bug 707679 - Non-Unix specific functions of the back-end. r=taras,dougt

This commit is contained in:
David Rajchenbach-Teller 2012-04-27 12:54:20 +02:00
parent 55b98f30b8
commit 728c8865f2
2 changed files with 454 additions and 0 deletions

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* Common front for various implementations of OS.File
*/
if (typeof Components != "undefined") {
// We do not wish osfile.jsm to be used directly as a main thread
// module yet.
throw new Error("osfile.jsm cannot be used from the main thread yet");
}
#ifdef XP_WIN
throw new Error("osfile.jsm not implemented for Windows platforms yet");
#else
importScripts("resource://gre/modules/osfile/osfile_unix_back.jsm");
#endif

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
{
if (typeof Components != "undefined") {
// We do not wish osfile_shared.jsm to be used directly as a main thread
// module yet. When time comes, it will be loaded by a combination of
// a main thread front-end/worker thread implementation that makes sure
// that we are not executing synchronous IO code in the main thread.
throw new Error("osfile_shared.jsm cannot be used from the main thread yet");
}
(function(exports) {
"use strict";
/*
* This block defines |OS.Shared.Type|. However, |OS| can exist already
* (in particular, if this code is executed in a worker thread, it is
* defined).
*/
if (!exports.OS) {
exports.OS = {};
}
if (!exports.OS.Shared) {
exports.OS.Shared = {};
}
if (exports.OS.Shared.Type) {
return; // Avoid double-initialization
}
let LOG;
if (typeof console != "undefined" && console.log) {
LOG = console.log.bind(console, "OS");
} else {
LOG = function() {
let text = "OS";
for (let i = 0; i < arguments.length; ++i) {
text += (" " + arguments[i]);
}
dump(text + "\n");
};
}
exports.OS.Shared.LOG = LOG;
/**
* An OS error.
*
* This class is provided mostly for type-matching. If you need more
* details about an error, you should use the platform-specific error
* codes provided by subclasses of |OS.Shared.Error|.
*
* @param {string} operation The operation that failed.
*
* @constructor
*/
function OSError(operation) {
Error.call(this);
this.operation = operation;
}
exports.OS.Shared.Error = OSError;
/**
* Abstraction above js-ctypes types.
*
* Use values of this type to register FFI functions. In addition to the
* usual features of js-ctypes, values of this type perform the necessary
* transformations to ensure that C errors are handled nicely, to connect
* resources with their finalizer, etc.
*
* @param {string} name The name of the type. Must be unique.
* @param {function=} convert_from_c A function to call to construct a
* value of this type from a C return value.
*
* @constructor
*/
function Type(name, implementation, convert_from_c) {
if (!(typeof name == "string")) {
throw new TypeError("Type expects as first argument a name, got: "
+ name);
}
if (!(implementation instanceof ctypes.CType)) {
throw new TypeError("Type expects as second argument a ctypes.CType"+
", got: " + implementation);
}
this.name = name;
this.implementation = implementation;
if (convert_from_c) {
this.convert_from_c = convert_from_c;
} else {// Optimization: Ensure harmony of shapes
this.convert_from_c = Type.prototype.convert_from_c;
}
}
Type.prototype = {
convert_from_c: function(value) {
return value;
},
/**
* A pointer/array used to pass data to the foreign function.
*/
get in_ptr() {
delete this.in_ptr;
let ptr_t = new Type("[int] " + this.name + "*",
this.implementation.ptr);
Object.defineProperty(this, "in_ptr",
{
get: function() {
return ptr_t;
}
});
return ptr_t;
},
/**
* A pointer/array used to receive data from the foreign function.
*/
get out_ptr() {
delete this.out_ptr;
let ptr_t = new Type("[out] " + this.name + "*",
this.implementation.ptr);
Object.defineProperty(this, "out_ptr",
{
get: function() {
return ptr_t;
}
});
return ptr_t;
},
/**
* A pointer/array used to both pass data to the foreign function
* and receive data from the foreign function.
*
* Whenever possible, prefer using |in_ptr| or |out_ptr|, which
* are generally faster.
*/
get inout_ptr() {
delete this.inout_ptr;
let ptr_t = new Type("[inout] " + this.name + "*",
this.implementation.ptr);
Object.defineProperty(this, "inout_ptr",
{
get: function() {
return ptr_t;
}
});
return ptr_t;
},
/**
* Attach a finalizer to a type.
*/
releaseWith: function(finalizer) {
let parent = this;
let type = new Type("[auto " + finalizer +"] " + this.name,
this.implementation,
function (value, operation) {
return ctypes.CDataFinalizer(
parent.convert_from_c(value, operation),
finalizer);
});
return type;
}
};
exports.OS.Shared.Type = Type;
let Types = Type;
/*
* Some values are large integers on 64 bit platforms. Unfortunately,
* in practice, 64 bit integers cannot be manipulated in JS. We
* therefore project them to regular numbers whenever possible.
*/
let projectLargeInt = function projectLargeInt(x) {
if (ctypes.Int64.hi(x)) {
throw new Error("Number too large " + x +
"(signed, hi: " + ctypes.Int64.hi(x) +
", lo:" + ctypes.Int64.lo(x) + ")");
}
return ctypes.Int64.lo(x);
};
let projectLargeUInt = function projectLargeUInt(x) {
if (ctypes.UInt64.hi(x)) {
throw new Error("Number too large " + x +
"(unsigned, hi: " + ctypes.UInt64.hi(x) +
", lo:" + ctypes.UInt64.lo(x) + ")");
}
return ctypes.UInt64.lo(x);
};
let projectValue = function projectValue(x) {
if (!(x instanceof ctypes.CData)) {
return x;
}
if (!("value" in x)) { // Sanity check
throw new TypeError("Number " + x.toSource() + " has no field |value|");
}
return x.value;
};
function projector(type, signed) {
if (!type.size) {
throw new TypeError("Argument is not a proper C type");
}
LOG("Determining best projection for", type,
"(size: ", type.size, ")", signed?"signed":"unsigned");
// Determine if type is projected to Int64/Uint64
if (type.size == 8 // Usual case
|| type == ctypes.size_t // Special cases
|| type == ctypes.ssize_t
|| type == ctypes.intptr_t
|| type == ctypes.uintptr_t
|| type == ctypes.off_t){
if (signed) {
LOG("Projected as a large signed integer");
return projectLargeInt;
} else {
LOG("Projected as a large unsigned integer");
return projectLargeUInt;
}
}
LOG("Projected as a regular number");
return projectValue;
};
/**
* Actual implementation of common C types.
*/
/**
* The void value.
*/
Types.void_t =
new Type("void",
ctypes.void_t);
/**
* Shortcut for |void*|.
*/
Types.voidptr_t =
new Type("void*",
ctypes.voidptr_t);
// void* is a special case as we can cast any pointer to/from it
// so we have to shortcut |in_ptr|/|out_ptr|/|inout_ptr| and
// ensure that js-ctypes' casting mechanism is invoked directly
["in_ptr", "out_ptr", "inout_ptr"].forEach(function(key) {
Object.defineProperty(Types.void_t, key,
{
get: function() {
return Types.voidptr_t;
}
});
});
/**
* A C char (one byte)
*/
Types.char =
new Type("char",
ctypes.char);
/**
* A C wide char (two bytes)
*/
Types.jschar =
new Type("jschar",
ctypes.jschar);
/**
* A C integer
*
* Size depends on the platform.
*/
Types.int =
new Type("int",
ctypes.int,
projector(ctypes.int, true));
Types.unsigned_int =
new Type("unsigned int",
ctypes.unsigned_int,
projector(ctypes.unsigned_int, false));
/**
* A C integer (32-bits).
*
* Also known as DWORD under Windows.
*/
Types.int32_t =
new Type("int32_t",
ctypes.int32_t,
projectValue);
Types.uint32_t =
new Type("uint32_t",
ctypes.uint32_t,
projectValue);
/**
* A C integer.
* Size depends on the platform.
*/
Types.long =
new Type("long",
ctypes.long,
projector(ctypes.long, true));
/**
* A boolean.
* Implemented as a C integer.
*/
Types.bool =
new Type("bool",
ctypes.int,
function projectBool(x) {
return !!(x.value);
});
/**
* A file access mode
* Implemented as a C integer.
*/
Types.mode_t =
new Type("mode_t",
ctypes.int,
projector(ctypes.int, true));
/**
* A user identifier.
* Implemented as a C integer.
*/
Types.uid_t =
new Type("uid_t",
ctypes.int,
projector(ctypes.int, true));
/**
* A group identifier.
* Implemented as a C integer.
*/
Types.gid_t =
new Type("gid_t",
ctypes.int,
projector(ctypes.int, true));
/**
* An offset (positive or negative).
* Implemented as a C integer.
*/
Types.off_t =
new Type("off_t",
ctypes.off_t,
projector(ctypes.off_t, true));
/**
* A size (positive).
* Implemented as a C size_t.
*/
Types.size_t =
new Type("size_t",
ctypes.size_t,
projector(ctypes.size_t, false));
/**
* An offset (positive or negative).
* Implemented as a C integer.
*/
Types.ssize_t =
new Type("ssize_t",
ctypes.ssize_t,
projector(ctypes.ssize_t, true));
/**
* Declare a function through js-ctypes
*
* @param {ctypes.library} lib The ctypes library holding the function.
* @param {string} symbol The name of the function, as defined in the
* library.
* @param {ctypes.abi} abi The abi to use, or |null| for default.
* @param {Type} returnType The type of values returned by the function.
* @param {...Type} argTypes The type of arguments to the function.
*
* @return null if the function could not be defined (generally because
* it does not exist), or a JavaScript wrapper performing the call to C
* and any type conversion required.
*/// Note: Future versions will use a different implementation of this
// function on the main thread, osfile worker thread and regular worker
// thread
let declareFFI = function declareFFI(lib, symbol, abi,
returnType /*, argTypes ...*/) {
LOG("Attempting to declare FFI ", symbol);
// We guard agressively, to avoid any late surprise
if (typeof symbol != "string") {
throw new TypeError("declareFFI expects as first argument a string");
}
abi = abi || ctypes.default_abi;
if (Object.prototype.toString.call(abi) != "[object CABI]") {
// Note: This is the only known manner of checking whether an object
// is an abi.
throw new TypeError("declareFFI expects as second argument an abi or null");
}
let signature = [symbol, abi];
let argtypes = [];
for (let i = 3; i < arguments.length; ++i) {
let current = arguments[i];
if (!current.implementation) {
throw new TypeError("Missing implementation for argument " + (i - 3)
+ " of symbol " + symbol
+ " ( " + current.name + " )" );
}
signature.push(current.implementation);
}
try {
let fun = lib.declare.apply(lib, signature);
let result = function ffi(/*arguments*/) {
let result = fun.apply(fun, arguments);
return returnType.convert_from_c(result, symbol);
};
if (exports.OS.Shared.DEBUG) {
result.fun = fun; // Also return the raw FFI function.
}
LOG("Function", symbol, "declared");
return result;
} catch (x) {
// Note: Not being able to declare a function is normal.
// Some functions are OS (or OS version)-specific.
LOG("Could not declare function " + symbol, x);
return null;
}
};
exports.OS.Shared.declareFFI = declareFFI;
})(this);
}