zip-iterator
Version:
Extract contents from zip archive type using an iterator API using streams or paths. Use stream interface and pipe transforms to add decompression algorithms
60 lines (59 loc) • 2.23 kB
JavaScript
/**
* Parse External File Attributes
*
* Extracts file type and permissions from ZIP external attributes.
* Based on: https://github.com/bower/decompress-zip/blob/master/lib/structures.js
*/ // Permission constants (decimal equivalents of octal for Node 0.8 compatibility)
const MODE_READ_ALL = 292; // 0o0444 - r--r--r--
const MODE_WRITE_ALL = 146; // 0o0222 - -w--w--w-
const MODE_EXEC_ALL = 73; // 0o0111 - --x--x--x
export default function parseExternalFileAttributes(externalAttributes, platform) {
const types = {
// In theory, any of these could be set. Realistically, though, it will
// be regular, directory or symlink
1: 'namedpipe',
2: 'character',
4: 'directory',
6: 'block',
8: 'file',
10: 'symlink',
12: 'socket'
};
switch(platform){
case 3:
return {
platform: 'Unix',
type: types[externalAttributes >> 28 & 0x0f] || 'file',
mode: externalAttributes >> 16 & 0xfff
};
// case 0: // MSDOS
default:
{
if (platform !== 0) {
console.warn(`Possibly unsupported ZIP platform type, ${platform}`);
}
const attribs = {
A: externalAttributes >> 5 & 0x01,
D: externalAttributes >> 4 & 0x01,
V: externalAttributes >> 3 & 0x01,
S: externalAttributes >> 2 & 0x01,
H: externalAttributes >> 1 & 0x01,
R: externalAttributes & 0x01
};
// With no better guidance we'll make the default permissions ugo+r
let mode = MODE_READ_ALL;
if (attribs.D) {
mode |= MODE_EXEC_ALL; // Set the execute bit
}
if (!attribs.R) {
mode |= MODE_WRITE_ALL; // Set the write bit
}
mode &= ~process.umask();
return {
platform: 'DOS',
type: attribs.D ? 'directory' : 'file',
mode: mode
};
}
}
}