diff options
Diffstat (limited to 'src/library_memfs.js')
| -rw-r--r-- | src/library_memfs.js | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/src/library_memfs.js b/src/library_memfs.js new file mode 100644 index 00000000..d3148d8b --- /dev/null +++ b/src/library_memfs.js @@ -0,0 +1,303 @@ +mergeInto(LibraryManager.library, { + $MEMFS__deps: ['$FS'], + $MEMFS: { + ops_table: null, + + // content modes + CONTENT_OWNING: 1, // contains a subarray into the heap, and we own it, without copying (note: someone else needs to free() it, if that is necessary) + CONTENT_FLEXIBLE: 2, // has been modified or never set to anything, and is a flexible js array that can grow/shrink + CONTENT_FIXED: 3, // contains some fixed-size content written into it, in a typed array + mount: function(mount) { + return MEMFS.createNode(null, '/', {{{ cDefine('S_IFDIR') }}} | 0777, 0); + }, + createNode: function(parent, name, mode, dev) { + if (FS.isBlkdev(mode) || FS.isFIFO(mode)) { + // no supported + throw new FS.ErrnoError(ERRNO_CODES.EPERM); + } + if (!MEMFS.ops_table) { + MEMFS.ops_table = { + dir: { + node: { + getattr: MEMFS.node_ops.getattr, + setattr: MEMFS.node_ops.setattr, + lookup: MEMFS.node_ops.lookup, + mknod: MEMFS.node_ops.mknod, + mknod: MEMFS.node_ops.mknod, + rename: MEMFS.node_ops.rename, + unlink: MEMFS.node_ops.unlink, + rmdir: MEMFS.node_ops.rmdir, + readdir: MEMFS.node_ops.readdir, + symlink: MEMFS.node_ops.symlink + }, + stream: { + llseek: MEMFS.stream_ops.llseek + } + }, + file: { + node: { + getattr: MEMFS.node_ops.getattr, + setattr: MEMFS.node_ops.setattr + }, + stream: { + llseek: MEMFS.stream_ops.llseek, + read: MEMFS.stream_ops.read, + write: MEMFS.stream_ops.write, + allocate: MEMFS.stream_ops.allocate, + mmap: MEMFS.stream_ops.mmap + } + }, + link: { + node: { + getattr: MEMFS.node_ops.getattr, + setattr: MEMFS.node_ops.setattr, + readlink: MEMFS.node_ops.readlink + }, + stream: {} + }, + chrdev: { + node: { + getattr: MEMFS.node_ops.getattr, + setattr: MEMFS.node_ops.setattr + }, + stream: FS.chrdev_stream_ops + }, + }; + } + var node = FS.createNode(parent, name, mode, dev); + if (FS.isDir(node.mode)) { + node.node_ops = MEMFS.ops_table.dir.node; + node.stream_ops = MEMFS.ops_table.dir.stream; + node.contents = {}; + } else if (FS.isFile(node.mode)) { + node.node_ops = MEMFS.ops_table.file.node; + node.stream_ops = MEMFS.ops_table.file.stream; + node.contents = []; + node.contentMode = MEMFS.CONTENT_FLEXIBLE; + } else if (FS.isLink(node.mode)) { + node.node_ops = MEMFS.ops_table.link.node; + node.stream_ops = MEMFS.ops_table.link.stream; + } else if (FS.isChrdev(node.mode)) { + node.node_ops = MEMFS.ops_table.chrdev.node; + node.stream_ops = MEMFS.ops_table.chrdev.stream; + } + node.timestamp = Date.now(); + // add the new node to the parent + if (parent) { + parent.contents[name] = node; + } + return node; + }, + ensureFlexible: function(node) { + if (node.contentMode !== MEMFS.CONTENT_FLEXIBLE) { + var contents = node.contents; + node.contents = Array.prototype.slice.call(contents); + node.contentMode = MEMFS.CONTENT_FLEXIBLE; + } + }, + node_ops: { + getattr: function(node) { + var attr = {}; + // device numbers reuse inode numbers. + attr.dev = FS.isChrdev(node.mode) ? node.id : 1; + attr.ino = node.id; + attr.mode = node.mode; + attr.nlink = 1; + attr.uid = 0; + attr.gid = 0; + attr.rdev = node.rdev; + if (FS.isDir(node.mode)) { + attr.size = 4096; + } else if (FS.isFile(node.mode)) { + attr.size = node.contents.length; + } else if (FS.isLink(node.mode)) { + attr.size = node.link.length; + } else { + attr.size = 0; + } + attr.atime = new Date(node.timestamp); + attr.mtime = new Date(node.timestamp); + attr.ctime = new Date(node.timestamp); + // NOTE: In our implementation, st_blocks = Math.ceil(st_size/st_blksize), + // but this is not required by the standard. + attr.blksize = 4096; + attr.blocks = Math.ceil(attr.size / attr.blksize); + return attr; + }, + setattr: function(node, attr) { + if (attr.mode !== undefined) { + node.mode = attr.mode; + } + if (attr.timestamp !== undefined) { + node.timestamp = attr.timestamp; + } + if (attr.size !== undefined) { + MEMFS.ensureFlexible(node); + var contents = node.contents; + if (attr.size < contents.length) contents.length = attr.size; + else while (attr.size > contents.length) contents.push(0); + } + }, + lookup: function(parent, name) { + throw FS.genericErrors[ERRNO_CODES.ENOENT]; + }, + mknod: function(parent, name, mode, dev) { + return MEMFS.createNode(parent, name, mode, dev); + }, + rename: function(old_node, new_dir, new_name) { + // if we're overwriting a directory at new_name, make sure it's empty. + if (FS.isDir(old_node.mode)) { + var new_node; + try { + new_node = FS.lookupNode(new_dir, new_name); + } catch (e) { + } + if (new_node) { + for (var i in new_node.contents) { + throw new FS.ErrnoError(ERRNO_CODES.ENOTEMPTY); + } + } + } + // do the internal rewiring + delete old_node.parent.contents[old_node.name]; + old_node.name = new_name; + new_dir.contents[new_name] = old_node; + old_node.parent = new_dir; + }, + unlink: function(parent, name) { + delete parent.contents[name]; + }, + rmdir: function(parent, name) { + var node = FS.lookupNode(parent, name); + for (var i in node.contents) { + throw new FS.ErrnoError(ERRNO_CODES.ENOTEMPTY); + } + delete parent.contents[name]; + }, + readdir: function(node) { + var entries = ['.', '..'] + for (var key in node.contents) { + if (!node.contents.hasOwnProperty(key)) { + continue; + } + entries.push(key); + } + return entries; + }, + symlink: function(parent, newname, oldpath) { + var node = MEMFS.createNode(parent, newname, 0777 | {{{ cDefine('S_IFLNK') }}}, 0); + node.link = oldpath; + return node; + }, + readlink: function(node) { + if (!FS.isLink(node.mode)) { + throw new FS.ErrnoError(ERRNO_CODES.EINVAL); + } + return node.link; + }, + }, + stream_ops: { + read: function(stream, buffer, offset, length, position) { + var contents = stream.node.contents; + if (position >= contents.length) + return 0; + var size = Math.min(contents.length - position, length); + assert(size >= 0); +#if USE_TYPED_ARRAYS == 2 + if (size > 8 && contents.subarray) { // non-trivial, and typed array + buffer.set(contents.subarray(position, position + size), offset); + } else +#endif + { + for (var i = 0; i < size; i++) { + buffer[offset + i] = contents[position + i]; + } + } + return size; + }, + write: function(stream, buffer, offset, length, position, canOwn) { + var node = stream.node; + node.timestamp = Date.now(); + var contents = node.contents; +#if USE_TYPED_ARRAYS == 2 + if (length && contents.length === 0 && position === 0 && buffer.subarray) { + // just replace it with the new data +#if ASSERTIONS + assert(buffer.length); +#endif + if (canOwn && offset === 0) { + node.contents = buffer; // this could be a subarray of Emscripten HEAP, or allocated from some other source. + node.contentMode = (buffer.buffer === HEAP8.buffer) ? MEMFS.CONTENT_OWNING : MEMFS.CONTENT_FIXED; + } else { + node.contents = new Uint8Array(buffer.subarray(offset, offset+length)); + node.contentMode = MEMFS.CONTENT_FIXED; + } + return length; + } +#endif + MEMFS.ensureFlexible(node); + var contents = node.contents; + while (contents.length < position) contents.push(0); + for (var i = 0; i < length; i++) { + contents[position + i] = buffer[offset + i]; + } + return length; + }, + llseek: function(stream, offset, whence) { + var position = offset; + if (whence === 1) { // SEEK_CUR. + position += stream.position; + } else if (whence === 2) { // SEEK_END. + if (FS.isFile(stream.node.mode)) { + position += stream.node.contents.length; + } + } + if (position < 0) { + throw new FS.ErrnoError(ERRNO_CODES.EINVAL); + } + stream.ungotten = []; + stream.position = position; + return position; + }, + allocate: function(stream, offset, length) { + MEMFS.ensureFlexible(stream.node); + var contents = stream.node.contents; + var limit = offset + length; + while (limit > contents.length) contents.push(0); + }, + mmap: function(stream, buffer, offset, length, position, prot, flags) { + if (!FS.isFile(stream.node.mode)) { + throw new FS.ErrnoError(ERRNO_CODES.ENODEV); + } + var ptr; + var allocated; + var contents = stream.node.contents; + // Only make a new copy when MAP_PRIVATE is specified. + if ( !(flags & {{{ cDefine('MAP_PRIVATE') }}}) && + (contents.buffer === buffer || contents.buffer === buffer.buffer) ) { + // We can't emulate MAP_SHARED when the file is not backed by the buffer + // we're mapping to (e.g. the HEAP buffer). + allocated = false; + ptr = contents.byteOffset; + } else { + // Try to avoid unnecessary slices. + if (position > 0 || position + length < contents.length) { + if (contents.subarray) { + contents = contents.subarray(position, position + length); + } else { + contents = Array.prototype.slice.call(contents, position, position + length); + } + } + allocated = true; + ptr = _malloc(length); + if (!ptr) { + throw new FS.ErrnoError(ERRNO_CODES.ENOMEM); + } + buffer.set(contents, ptr); + } + return { ptr: ptr, allocated: allocated }; + }, + } + } +}); + |