/
unmarshall.js
240 lines (229 loc) · 7.85 KB
/
unmarshall.js
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var put = require('put');
var binary = require('binary');
var parseSignature = require('./signature');
var assert = require('assert');
//var constants = require('./constants');
var exports = module.exports = function (signature, offset, callback) {
var bs = this;
if (signature === "")
return callback(null, null);
var args = parseSignature(signature);
bs.globalOffset = offset;
readStruct(bs, args, callback);
};
var align = module.exports.align = function align(bs, power) {
var allbits = (1<<power) - 1;
var paddedOffset = ((bs.globalOffset + allbits) >> power) << power;
var toAlign = paddedOffset - bs.globalOffset;
if (toAlign !== 0) {
bs.globalOffset += toAlign;
bs.skip(toAlign);
}
};
function read(bs, tree, callback)
{
switch (tree.type) {
case '(':
case '{':
align(bs, 3); // align to 8 bytes boundary
return readStruct(bs, tree.child, callback);
case 'a':
if (!tree.child || tree.child.length != 1)
throw new Error('Incorrect array element signature');
align(bs, 2);
bs.globalOffset += 4;
bs.word32le('length').buffer('arrayBuffer', 'length').tap(function(vars) {
var arrayBuffer = binary(vars.arrayBuffer);
arrayBuffer.globalOffset = bs.globalOffset;
return readArray(arrayBuffer, tree.child[0], vars.length, function(err, value) {
bs.globalOffset += vars.length;
callback(err, value);
});
});
break;
case 'v':
return readVariant(bs, callback);
default:
readSimpleType(bs, tree.type, callback);
}
}
function readVariant(bs, callback)
{
//var cb = callback;
//callback = function(err, val) {
// console.log("READ VARIANT RESULT: ", err, val);
// cb(err, val);
//}
readSimpleType(bs, 'g', function(err, val) {
if (err)
return callback(err);
var args;
try { // TODO use CPS-style for parseSignature for consistency?
args = parseSignature(val);
} catch(err) {
return callback(err);
}
readStruct(bs, args, function(err, val) {
if (err)
return callback(err);
return callback(null, [args, val]);
});
});
}
function readStruct(bs, struct, callback)
{
//var cb = callback;
//callback = function(err, val) {
// console.log("READ STRUCT RESULT: ", err, JSON.stringify(val, null, 4));
// cb(err, val);
//}
var result = [];
if (struct.length === 0)
callback(null, result);
function readElement(index) {
read(bs, struct[index], function(err, value) {
if (err) {
//console.log("ERROR", debug_value);
return callback(null, result);
}
result.push(value);
if (index + 1 < struct.length) {
readElement(index + 1);
} else {
callback(null, result);
}
});
}
readElement(0);
}
function readArray(bs, ele, length, callback)
{
//var cb = callback;
//callback = function(err, val) {
// console.log("READ ARRAY RESULT: ", err, val);
// cb(err, val);
//}
var result = [];
function readElement() {
if (!bs.eof()) {
read(bs, ele, function(err, value) {
if (err)
return callback(err);
result.push(value);
readElement();
});
} else {
return callback(null, result);
}
}
readElement();
}
function readSimpleType(bs, t, callback)
{
//var cb = callback;
//callback = function(err, val) {
// console.log("RESULT: ", err, val);
// cb(err, val);
//}
switch (t) {
case 'y':
bs.globalOffset += 1;
return bs.word8('param').tap(function(vars) { callback(null, vars.param); });
case 'n':
align(bs, 1);
bs.globalOffset += 2;
return bs.word16ls('param').tap(function(vars) { callback(null, vars.param); });
case 'q':
align(bs, 1);
bs.globalOffset += 2;
return bs.word16le('param').tap(function(vars) { callback(null, vars.param); });
case 'u':
case 'b':
align(bs, 2); // align to 4 bytes boundary
bs.globalOffset += 4;
return bs.word32le('param').tap(function(vars) {
if (t === 'b' && !isValidBoolean(vars.param)) {
//console.log('GOT BOOLEAN', vars.param);
callback(new Error('booleans are allowed to be 0 or 1'));
} else
callback(null, vars.param);
});
case 'i':
align(bs, 2);
bs.globalOffset += 4;
/*
return bs.word32le('param')
.tap(function(vars) {
if (vars.param === null)
debugger;
callback(null, vars.param);
});
*/
return bs.buffer('buff', 4).tap(function(vars) {
var param = vars.buff.readInt32LE(0);
callback(null, param);
});
case 'g':
return bs.word8('length').tap(function(vars) {
bs.buffer('signature', vars.length + 1).tap(function(vars) {
bs.globalOffset += vars.length + 2; // byte length + null terminator
var sig = vars.signature.slice(0, vars.length).toString('ascii');
callback(null, sig);
});
});
case 's':
case 'o':
align(bs, 2);
return bs.word32le('length').tap(function(vars) {
var len = vars.length;
// TODO: oob checks for strings
bs.buffer('buff', len+1).tap(function(vars) {
bs.globalOffset += len + 5;
//console.log('UNMARSHALL STRING: length=', len, vars.buff.length, vars.length);
//if (len > vars.buff.length) {
// return callback(new Error('Incorrect string length'));
//}
var str = vars.buff.slice(0, vars.buff.length-1).toString('utf8');
if (t === 'o' && !isValidObjectPath(str))
return callback(new Error('string is not a valid object path'));
else return callback(null, str);
});
});
case 'x': //signed
align(bs, 3);
bs.globalOffset += 8;
return bs.word64ls('param').tap(function(vars) { callback(null, vars.param); });
case 't': //unsigned
align(bs, 3);
bs.globalOffset += 8;
return bs.word64le('param').tap(function(vars) { callback(null, vars.param); });
case 'd': //unsigned
align(bs, 3);
bs.globalOffset += 8;
return bs.buffer('param', 8).tap(function(vars) { callback(null, vars.param.readFloatLE(0)); });
default:
console.log('Unsupported type:' + t);
callback(new Error('Unsupported type:' + t));
throw new Error('Unsupported type:' + t);
}
}
function isValidBoolean(val) {
return val === 1 || val === 0;
}
/*
http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-marshaling
The following rules define a valid object path.
Implementations must not send or accept messages with invalid object paths.
- The path may be of any length.
- The path must begin with an ASCII '/'
(integer 47) character, and must consist of elements
separated by slash characters.
- Each element must only contain the ASCII characters "[A-Z][a-z][0-9]_"
- No element may be the empty string.
- Multiple '/' characters cannot occur in sequence.
- A trailing '/' character is not allowed unless the path is the root path (a single '/' character).
*/
// the above is copy-paste from spec. I believe they meant /^(\/$)|(\/[A-Za-z0-9_]+)+$/
function isValidObjectPath(path) {
return path.match(/^(\/$)|(\/[A-Za-z0-9_]+)+$/);
}