mergeInto(LibraryManager.library, { $MEMFS__deps: ['$FS'], $MEMFS: { ops_table: null, mount: function(mount) { return MEMFS.createNode(null, '/', {{{ cDefine('S_IFDIR') }}} | 511 /* 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, 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.usedBytes = 0; // The actual number of bytes used in the typed array, as opposed to contents.buffer.byteLength which gives the whole capacity. // When the byte data of the file is populated, this will point to either a typed array, or a normal JS array. Typed arrays are preferred // for performance, and used by default. However, typed arrays are not resizable like normal JS arrays are, so there is a small disk size // penalty involved for appending file writes that continuously grow a file similar to std::vector capacity vs used -scheme. node.contents = null; } 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; }, // Given a file node, returns its file data converted to a regular JS array. You should treat this as read-only. getFileDataAsRegularArray: function(node) { #if USE_TYPED_ARRAYS == 2 if (node.contents && node.contents.subarray) { var arr = []; for (var i = 0; i < node.usedBytes; ++i) arr.push(node.contents[i]); return arr; // Returns a copy of the original data. } #endif return node.contents; // No-op, the file contents are already in a JS array. Return as-is. }, #if USE_TYPED_ARRAYS == 2 // Given a file node, returns its file data converted to a typed array. getFileDataAsTypedArray: function(node) { if (node.contents && node.contents.subarray) return node.contents.subarray(0, node.usedBytes); // Make sure to not return excess unused bytes. return new Uint8Array(node.contents); }, #endif // Allocates a new backing store for the given node so that it can fit at least newSize amount of bytes. // May allocate more, to provide automatic geometric increase and amortized linear performance appending writes. // Never shrinks the storage. expandFileStorage: function(node, newCapacity) { #if USE_TYPED_ARRAYS == 2 #if !MEMFS_APPEND_TO_TYPED_ARRAYS // If we are asked to expand the size of a file that already exists, revert to using a standard JS array to store the file // instead of a typed array. This makes resizing the array more flexible because we can just .push() elements at the back to // increase the size. if (node.contents && node.contents.subarray && newCapacity > node.contents.length) { node.contents = MEMFS.getFileDataAsRegularArray(node); node.usedBytes = node.contents.length; // We might be writing to a lazy-loaded file which had overridden this property, so force-reset it. } #endif if (!node.contents || node.contents.subarray) { // Keep using a typed array if creating a new storage, or if old one was a typed array as well. var prevCapacity = node.contents ? node.contents.buffer.byteLength : 0; if (prevCapacity >= newCapacity) return; // No need to expand, the storage was already large enough. // Don't expand strictly to the given requested limit if it's only a very small increase, but instead geometrically grow capacity. // For small filesizes (<1MB), perform size*2 geometric increase, but for large sizes, do a much more conservative size*1.125 increase to // avoid overshooting the allocation cap by a very large margin. var CAPACITY_DOUBLING_MAX = 1024 * 1024; newCapacity = Math.max(newCapacity, (prevCapacity * (prevCapacity < CAPACITY_DOUBLING_MAX ? 2.0 : 1.125)) | 0); if (prevCapacity != 0) newCapacity = Math.max(newCapacity, 256); // At minimum allocate 256b for each file when expanding. var oldContents = node.contents; node.contents = new Uint8Array(newCapacity); // Allocate new storage. if (node.usedBytes > 0) node.contents.set(oldContents.subarray(0, node.usedBytes), 0); // Copy old data over to the new storage. return; } #endif // Not using a typed array to back the file storage. Use a standard JS array instead. if (!node.contents && newCapacity > 0) node.contents = []; while (node.contents.length < newCapacity) node.contents.push(0); }, // Performs an exact resize of the backing file storage to the given size, if the size is not exactly this, the storage is fully reallocated. resizeFileStorage: function(node, newSize) { if (node.usedBytes == newSize) return; if (newSize == 0) { node.contents = null; // Fully decommit when requesting a resize to zero. node.usedBytes = 0; return; } #if USE_TYPED_ARRAYS == 2 if (!node.contents || node.contents.subarray) { // Resize a typed array if that is being used as the backing store. var oldContents = node.contents; node.contents = new Uint8Array(new ArrayBuffer(newSize)); // Allocate new storage. node.contents.set(oldContents.subarray(0, Math.min(newSize, node.usedBytes))); // Copy old data over to the new storage. node.usedBytes = newSize; return; } #endif // Backing with a JS array. if (!node.contents) node.contents = []; if (node.contents.length > newSize) node.contents.length = newSize; else while (node.contents.length < newSize) node.contents.push(0); node.usedBytes = newSize; }, 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.usedBytes; } 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.resizeFileStorage(node, attr.size); } }, 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, 511 /* 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 >= stream.node.usedBytes) return 0; var size = Math.min(stream.node.usedBytes - 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; }, // Writes the byte range (buffer[offset], buffer[offset+length]) to offset 'position' into the file pointed by 'stream' write: function(stream, buffer, offset, length, position, canOwn) { if (!length) return 0; var node = stream.node; node.timestamp = Date.now(); #if USE_TYPED_ARRAYS == 2 if (buffer.subarray && (!node.contents || node.contents.subarray)) { // This write is from a typed array to a typed array? if (canOwn) { // Can we just reuse the buffer we are given? #if ASSERTIONS assert(position === 0, 'canOwn must imply no weird position inside the file'); #endif node.contents = buffer.subarray(offset, offset + length); node.usedBytes = length; return length; } else if (node.usedBytes === 0 && position === 0) { // If this is a simple first write to an empty file, do a fast set since we don't need to care about old data. node.contents = new Uint8Array(buffer.subarray(offset, offset + length)); node.usedBytes = length; return length; } else if (position + length <= node.usedBytes) { // Writing to an already allocated and used subrange of the file? node.contents.set(buffer.subarray(offset, offset + length), position); return length; } } #endif // Appending to an existing file and we need to reallocate, or source data did not come as a typed array. MEMFS.expandFileStorage(node, position+length); #if USE_TYPED_ARRAYS == 2 if (node.contents.subarray && buffer.subarray) node.contents.set(buffer.subarray(offset, offset + length), position); // Use typed array write if available. else #endif for (var i = 0; i < length; i++) { node.contents[position + i] = buffer[offset + i]; // Or fall back to manual write if not. } node.usedBytes = Math.max(node.usedBytes, position+length); 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.usedBytes; } } if (position < 0) { throw new FS.ErrnoError(ERRNO_CODES.EINVAL); } stream.ungotten = []; stream.position = position; return position; }, allocate: function(stream, offset, length) { MEMFS.expandFileStorage(stream.node, offset + length); stream.node.usedBytes = Math.max(stream.node.usedBytes, offset + length); }, 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 < stream.node.usedBytes) { 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 }; }, } } });