106 lines
2.9 KiB
JavaScript
106 lines
2.9 KiB
JavaScript
|
'use strict';
|
||
|
|
|
||
|
|
var fs = require('fs');
|
||
|
|
var path = require('path');
|
||
|
|
|
||
|
|
var detector = require('./detector');
|
||
|
|
|
||
|
|
var handlers = {};
|
||
|
|
var types = require('./types');
|
||
|
|
|
||
|
|
// load all available handlers
|
||
|
|
types.forEach(function (type) {
|
||
|
|
handlers[type] = require('./types/' + type);
|
||
|
|
});
|
||
|
|
|
||
|
|
// Maximum buffer size, with a default of 128 kilobytes.
|
||
|
|
// TO-DO: make this adaptive based on the initial signature of the image
|
||
|
|
var MaxBufferSize = 128*1024;
|
||
|
|
|
||
|
|
function lookup (buffer, filepath) {
|
||
|
|
// detect the file type.. don't rely on the extension
|
||
|
|
var type = detector(buffer, filepath);
|
||
|
|
|
||
|
|
// find an appropriate handler for this file type
|
||
|
|
if (type in handlers) {
|
||
|
|
var size = handlers[type].calculate(buffer, filepath);
|
||
|
|
if (size !== false) {
|
||
|
|
size.type = type;
|
||
|
|
return size;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// throw up, if we don't understand the file
|
||
|
|
throw new TypeError('unsupported file type: ' + type + ' (file: ' + filepath + ')');
|
||
|
|
}
|
||
|
|
|
||
|
|
function asyncFileToBuffer (filepath, callback) {
|
||
|
|
// open the file in read only mode
|
||
|
|
fs.open(filepath, 'r', function (err, descriptor) {
|
||
|
|
if (err) { return callback(err); }
|
||
|
|
var size = fs.fstatSync(descriptor).size;
|
||
|
|
if (size <= 0){return callback(new Error("File size is not greater than 0 —— " + filepath)); }
|
||
|
|
var bufferSize = Math.min(size, MaxBufferSize);
|
||
|
|
var buffer = new Buffer(bufferSize);
|
||
|
|
// read first buffer block from the file, asynchronously
|
||
|
|
fs.read(descriptor, buffer, 0, bufferSize, 0, function (err) {
|
||
|
|
if (err) { return callback(err); }
|
||
|
|
// close the file, we are done
|
||
|
|
fs.close(descriptor, function (err) {
|
||
|
|
callback(err, buffer);
|
||
|
|
});
|
||
|
|
});
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
function syncFileToBuffer (filepath) {
|
||
|
|
// read from the file, synchronously
|
||
|
|
var descriptor = fs.openSync(filepath, 'r');
|
||
|
|
var size = fs.fstatSync(descriptor).size;
|
||
|
|
var bufferSize = Math.min(size, MaxBufferSize);
|
||
|
|
var buffer = new Buffer(bufferSize);
|
||
|
|
fs.readSync(descriptor, buffer, 0, bufferSize, 0);
|
||
|
|
fs.closeSync(descriptor);
|
||
|
|
return buffer;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @params input - buffer or relative/absolute path of the image file
|
||
|
|
* @params callback - optional function for async detection
|
||
|
|
*/
|
||
|
|
module.exports = function (input, callback) {
|
||
|
|
|
||
|
|
// Handle buffer input
|
||
|
|
if (Buffer.isBuffer(input)) {
|
||
|
|
return lookup(input);
|
||
|
|
}
|
||
|
|
|
||
|
|
// input should be a string at this point
|
||
|
|
if (typeof input !== 'string') {
|
||
|
|
throw new TypeError('invalid invocation');
|
||
|
|
}
|
||
|
|
|
||
|
|
// resolve the file path
|
||
|
|
var filepath = path.resolve(input);
|
||
|
|
|
||
|
|
if (typeof callback === 'function') {
|
||
|
|
asyncFileToBuffer(filepath, function (err, buffer) {
|
||
|
|
if (err) { return callback(err); }
|
||
|
|
|
||
|
|
// return the dimensions
|
||
|
|
var dimensions;
|
||
|
|
try {
|
||
|
|
dimensions = lookup(buffer, filepath);
|
||
|
|
} catch (e) {
|
||
|
|
err = e;
|
||
|
|
}
|
||
|
|
callback(err, dimensions);
|
||
|
|
});
|
||
|
|
} else {
|
||
|
|
var buffer = syncFileToBuffer(filepath);
|
||
|
|
return lookup(buffer, filepath);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
module.exports.types = types;
|