promisify.js 11.9 KB
Newer Older
liang ce committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314
"use strict";
module.exports = function(Promise, INTERNAL) {
var THIS = {};
var util = require("./util");
var nodebackForPromise = require("./nodeback");
var withAppended = util.withAppended;
var maybeWrapAsError = util.maybeWrapAsError;
var canEvaluate = util.canEvaluate;
var TypeError = require("./errors").TypeError;
var defaultSuffix = "Async";
var defaultPromisified = {__isPromisified__: true};
var noCopyProps = [
    "arity",    "length",
    "name",
    "arguments",
    "caller",
    "callee",
    "prototype",
    "__isPromisified__"
];
var noCopyPropsPattern = new RegExp("^(?:" + noCopyProps.join("|") + ")$");

var defaultFilter = function(name) {
    return util.isIdentifier(name) &&
        name.charAt(0) !== "_" &&
        name !== "constructor";
};

function propsFilter(key) {
    return !noCopyPropsPattern.test(key);
}

function isPromisified(fn) {
    try {
        return fn.__isPromisified__ === true;
    }
    catch (e) {
        return false;
    }
}

function hasPromisified(obj, key, suffix) {
    var val = util.getDataPropertyOrDefault(obj, key + suffix,
                                            defaultPromisified);
    return val ? isPromisified(val) : false;
}
function checkValid(ret, suffix, suffixRegexp) {
    for (var i = 0; i < ret.length; i += 2) {
        var key = ret[i];
        if (suffixRegexp.test(key)) {
            var keyWithoutAsyncSuffix = key.replace(suffixRegexp, "");
            for (var j = 0; j < ret.length; j += 2) {
                if (ret[j] === keyWithoutAsyncSuffix) {
                    throw new TypeError("Cannot promisify an API that has normal methods with '%s'-suffix\u000a\u000a    See http://goo.gl/MqrFmX\u000a"
                        .replace("%s", suffix));
                }
            }
        }
    }
}

function promisifiableMethods(obj, suffix, suffixRegexp, filter) {
    var keys = util.inheritedDataKeys(obj);
    var ret = [];
    for (var i = 0; i < keys.length; ++i) {
        var key = keys[i];
        var value = obj[key];
        var passesDefaultFilter = filter === defaultFilter
            ? true : defaultFilter(key, value, obj);
        if (typeof value === "function" &&
            !isPromisified(value) &&
            !hasPromisified(obj, key, suffix) &&
            filter(key, value, obj, passesDefaultFilter)) {
            ret.push(key, value);
        }
    }
    checkValid(ret, suffix, suffixRegexp);
    return ret;
}

var escapeIdentRegex = function(str) {
    return str.replace(/([$])/, "\\$");
};

var makeNodePromisifiedEval;
if (!false) {
var switchCaseArgumentOrder = function(likelyArgumentCount) {
    var ret = [likelyArgumentCount];
    var min = Math.max(0, likelyArgumentCount - 1 - 3);
    for(var i = likelyArgumentCount - 1; i >= min; --i) {
        ret.push(i);
    }
    for(var i = likelyArgumentCount + 1; i <= 3; ++i) {
        ret.push(i);
    }
    return ret;
};

var argumentSequence = function(argumentCount) {
    return util.filledRange(argumentCount, "_arg", "");
};

var parameterDeclaration = function(parameterCount) {
    return util.filledRange(
        Math.max(parameterCount, 3), "_arg", "");
};

var parameterCount = function(fn) {
    if (typeof fn.length === "number") {
        return Math.max(Math.min(fn.length, 1023 + 1), 0);
    }
    return 0;
};

makeNodePromisifiedEval =
function(callback, receiver, originalName, fn, _, multiArgs) {
    var newParameterCount = Math.max(0, parameterCount(fn) - 1);
    var argumentOrder = switchCaseArgumentOrder(newParameterCount);
    var shouldProxyThis = typeof callback === "string" || receiver === THIS;

    function generateCallForArgumentCount(count) {
        var args = argumentSequence(count).join(", ");
        var comma = count > 0 ? ", " : "";
        var ret;
        if (shouldProxyThis) {
            ret = "ret = callback.call(this, {{args}}, nodeback); break;\n";
        } else {
            ret = receiver === undefined
                ? "ret = callback({{args}}, nodeback); break;\n"
                : "ret = callback.call(receiver, {{args}}, nodeback); break;\n";
        }
        return ret.replace("{{args}}", args).replace(", ", comma);
    }

    function generateArgumentSwitchCase() {
        var ret = "";
        for (var i = 0; i < argumentOrder.length; ++i) {
            ret += "case " + argumentOrder[i] +":" +
                generateCallForArgumentCount(argumentOrder[i]);
        }

        ret += "                                                             \n\
        default:                                                             \n\
            var args = new Array(len + 1);                                   \n\
            var i = 0;                                                       \n\
            for (var i = 0; i < len; ++i) {                                  \n\
               args[i] = arguments[i];                                       \n\
            }                                                                \n\
            args[i] = nodeback;                                              \n\
            [CodeForCall]                                                    \n\
            break;                                                           \n\
        ".replace("[CodeForCall]", (shouldProxyThis
                                ? "ret = callback.apply(this, args);\n"
                                : "ret = callback.apply(receiver, args);\n"));
        return ret;
    }

    var getFunctionCode = typeof callback === "string"
                                ? ("this != null ? this['"+callback+"'] : fn")
                                : "fn";
    var body = "'use strict';                                                \n\
        var ret = function (Parameters) {                                    \n\
            'use strict';                                                    \n\
            var len = arguments.length;                                      \n\
            var promise = new Promise(INTERNAL);                             \n\
            promise._captureStackTrace();                                    \n\
            var nodeback = nodebackForPromise(promise, " + multiArgs + ");   \n\
            var ret;                                                         \n\
            var callback = tryCatch([GetFunctionCode]);                      \n\
            switch(len) {                                                    \n\
                [CodeForSwitchCase]                                          \n\
            }                                                                \n\
            if (ret === errorObj) {                                          \n\
                promise._rejectCallback(maybeWrapAsError(ret.e), true, true);\n\
            }                                                                \n\
            if (!promise._isFateSealed()) promise._setAsyncGuaranteed();     \n\
            return promise;                                                  \n\
        };                                                                   \n\
        notEnumerableProp(ret, '__isPromisified__', true);                   \n\
        return ret;                                                          \n\
    ".replace("[CodeForSwitchCase]", generateArgumentSwitchCase())
        .replace("[GetFunctionCode]", getFunctionCode);
    body = body.replace("Parameters", parameterDeclaration(newParameterCount));
    return new Function("Promise",
                        "fn",
                        "receiver",
                        "withAppended",
                        "maybeWrapAsError",
                        "nodebackForPromise",
                        "tryCatch",
                        "errorObj",
                        "notEnumerableProp",
                        "INTERNAL",
                        body)(
                    Promise,
                    fn,
                    receiver,
                    withAppended,
                    maybeWrapAsError,
                    nodebackForPromise,
                    util.tryCatch,
                    util.errorObj,
                    util.notEnumerableProp,
                    INTERNAL);
};
}

function makeNodePromisifiedClosure(callback, receiver, _, fn, __, multiArgs) {
    var defaultThis = (function() {return this;})();
    var method = callback;
    if (typeof method === "string") {
        callback = fn;
    }
    function promisified() {
        var _receiver = receiver;
        if (receiver === THIS) _receiver = this;
        var promise = new Promise(INTERNAL);
        promise._captureStackTrace();
        var cb = typeof method === "string" && this !== defaultThis
            ? this[method] : callback;
        var fn = nodebackForPromise(promise, multiArgs);
        try {
            cb.apply(_receiver, withAppended(arguments, fn));
        } catch(e) {
            promise._rejectCallback(maybeWrapAsError(e), true, true);
        }
        if (!promise._isFateSealed()) promise._setAsyncGuaranteed();
        return promise;
    }
    util.notEnumerableProp(promisified, "__isPromisified__", true);
    return promisified;
}

var makeNodePromisified = canEvaluate
    ? makeNodePromisifiedEval
    : makeNodePromisifiedClosure;

function promisifyAll(obj, suffix, filter, promisifier, multiArgs) {
    var suffixRegexp = new RegExp(escapeIdentRegex(suffix) + "$");
    var methods =
        promisifiableMethods(obj, suffix, suffixRegexp, filter);

    for (var i = 0, len = methods.length; i < len; i+= 2) {
        var key = methods[i];
        var fn = methods[i+1];
        var promisifiedKey = key + suffix;
        if (promisifier === makeNodePromisified) {
            obj[promisifiedKey] =
                makeNodePromisified(key, THIS, key, fn, suffix, multiArgs);
        } else {
            var promisified = promisifier(fn, function() {
                return makeNodePromisified(key, THIS, key,
                                           fn, suffix, multiArgs);
            });
            util.notEnumerableProp(promisified, "__isPromisified__", true);
            obj[promisifiedKey] = promisified;
        }
    }
    util.toFastProperties(obj);
    return obj;
}

function promisify(callback, receiver, multiArgs) {
    return makeNodePromisified(callback, receiver, undefined,
                                callback, null, multiArgs);
}

Promise.promisify = function (fn, options) {
    if (typeof fn !== "function") {
        throw new TypeError("expecting a function but got " + util.classString(fn));
    }
    if (isPromisified(fn)) {
        return fn;
    }
    options = Object(options);
    var receiver = options.context === undefined ? THIS : options.context;
    var multiArgs = !!options.multiArgs;
    var ret = promisify(fn, receiver, multiArgs);
    util.copyDescriptors(fn, ret, propsFilter);
    return ret;
};

Promise.promisifyAll = function (target, options) {
    if (typeof target !== "function" && typeof target !== "object") {
        throw new TypeError("the target of promisifyAll must be an object or a function\u000a\u000a    See http://goo.gl/MqrFmX\u000a");
    }
    options = Object(options);
    var multiArgs = !!options.multiArgs;
    var suffix = options.suffix;
    if (typeof suffix !== "string") suffix = defaultSuffix;
    var filter = options.filter;
    if (typeof filter !== "function") filter = defaultFilter;
    var promisifier = options.promisifier;
    if (typeof promisifier !== "function") promisifier = makeNodePromisified;

    if (!util.isIdentifier(suffix)) {
        throw new RangeError("suffix must be a valid identifier\u000a\u000a    See http://goo.gl/MqrFmX\u000a");
    }

    var keys = util.inheritedDataKeys(target);
    for (var i = 0; i < keys.length; ++i) {
        var value = target[keys[i]];
        if (keys[i] !== "constructor" &&
            util.isClass(value)) {
            promisifyAll(value.prototype, suffix, filter, promisifier,
                multiArgs);
            promisifyAll(value, suffix, filter, promisifier, multiArgs);
        }
    }

    return promisifyAll(target, suffix, filter, promisifier, multiArgs);
};
};