Class WASI

constructor

• new WASI(context): WASI

• Parameters

  • context: Partial<WASIContextOptions>

  Returns WASI

context

drive

hasBeenInitialized

instance

memory

module

envArray

• get envArray(): string[]

• Returns string[]

args_get

• args_get(argv_ptr, argv_buf_ptr): number

• Read command-line argument data. The size of the array should match that returned by args_sizes_get. Each argument is expected to be \0 terminated.

  Parameters

  • argv_ptr: number

  • argv_buf_ptr: number

  Returns number

args_sizes_get

• args_sizes_get(argc_ptr, argv_buf_size_ptr): number

• Return command-line argument data sizes.

  Parameters

  • argc_ptr: number

  • argv_buf_size_ptr: number

  Returns number

clock_res_get

• clock_res_get(id, retptr0): number

• Return the resolution of a clock. Implementations are required to provide a non-zero value for supported clocks. For unsupported clocks, return errno::inval. Note: This is similar to clock_getres in POSIX.

  Parameters

  • id: number

  • retptr0: number

  Returns number

clock_time_get

• clock_time_get(id, _, retptr0): number

• Return the time value of a clock. Note: This is similar to clock_gettime in POSIX.

  Parameters

  • id: number

  • _: bigint

  • retptr0: number

  Returns number

environ_get

• environ_get(env_ptr_ptr, env_buf_ptr): number

• Read environment variable data. The sizes of the buffers should match that returned by environ_sizes_get. Key/value pairs are expected to be joined with =s, and terminated with \0s.

  Parameters

  • env_ptr_ptr: number

  • env_buf_ptr: number

  Returns number

environ_sizes_get

• environ_sizes_get(env_ptr, env_buf_size_ptr): number

• Return environment variable data sizes.

  Parameters

  • env_ptr: number

  • env_buf_size_ptr: number

  Returns number

fd_advise

• fd_advise(): number

• Provide file advisory information on a file descriptor. Note: This is similar to posix_fadvise in POSIX.

  Returns number

fd_allocate

• fd_allocate(fd, offset, length): number

• Force the allocation of space in a file. Note: This is similar to posix_fallocate in POSIX.

  Parameters

  • fd: number

  • offset: bigint

  • length: bigint

  Returns number

fd_close

• fd_close(fd): Result

• Close a file descriptor. Note: This is similar to close in POSIX.

  Parameters

  • fd: number

  Returns Result

fd_datasync

• fd_datasync(fd): Result

• Synchronize the data of a file to disk. Note: This is similar to fdatasync in POSIX.

  Parameters

  • fd: number

  Returns Result

fd_fdstat_get

• fd_fdstat_get(fd, retptr0): number

• Get the attributes of a file descriptor. Note: This returns similar flags to fsync(fd, F_GETFL) in POSIX, as well as additional fields.

  Returns fdstat - the buffer where the file descriptor's attributes are stored.

  Parameters

  • fd: number

  • retptr0: number

  Returns number

  Result<fdstat, errno>

fd_fdstat_set_flags

• fd_fdstat_set_flags(fd, flags): number

• Adjust the flags associated with a file descriptor. Note: This is similar to fcntl(fd, F_SETFL, flags) in POSIX.

  Parameters

  • fd: number

  • flags: number

  Returns number

fd_fdstat_set_rights

• fd_fdstat_set_rights(): Result

• Adjust the rights associated with a file descriptor. This can only be used to remove rights, and returns errno::notcapable if called in a way that would attempt to add rights

  Returns Result

fd_filestat_get

• fd_filestat_get(fd, retptr0): number

• Return the attributes of an open file.

  Parameters

  • fd: number

  • retptr0: number

  Returns number

fd_filestat_set_size

• fd_filestat_set_size(fd, size): number

• Adjust the size of an open file. If this increases the file's size, the extra bytes are filled with zeros. Note: This is similar to ftruncate in POSIX.

  Parameters

  • fd: number

  • size: bigint

  Returns number

fd_filestat_set_times

• fd_filestat_set_times(fd, atim, mtim, fst_flags): number

• Adjust the timestamps of an open file or directory. Note: This is similar to futimens in POSIX.

  Parameters

  • fd: number

  • atim: bigint

  • mtim: bigint

  • fst_flags: number

  Returns number

fd_pread

• fd_pread(fd, iovs_ptr, iovs_len, offset, retptr0): number

• Read from a file descriptor, without using and updating the file descriptor's offset. Note: This is similar to preadv in POSIX.

  Parameters

  • fd: number

  • iovs_ptr: number

  • iovs_len: number

  • offset: bigint

  • retptr0: number

  Returns number

fd_prestat_dir_name

• fd_prestat_dir_name(fd, path_ptr, path_len): number

• Return a description of the given preopened file descriptor.

  Parameters

  • fd: number

  • path_ptr: number

  • path_len: number

  Returns number

fd_prestat_get

• fd_prestat_get(fd, retptr0): number

• Return a description of the given preopened file descriptor.

  Parameters

  • fd: number

  • retptr0: number

  Returns number

fd_pwrite

• fd_pwrite(fd, ciovs_ptr, ciovs_len, offset, retptr0): number

• Write to a file descriptor, without using and updating the file descriptor's offset. Note: This is similar to pwritev in POSIX.

  Parameters

  • fd: number

  • ciovs_ptr: number

  • ciovs_len: number

  • offset: bigint

  • retptr0: number

  Returns number

fd_read

• fd_read(fd, iovs_ptr, iovs_len, retptr0): number

• Read from a file descriptor. Note: This is similar to readv in POSIX.

  Parameters

  • fd: number

  • iovs_ptr: number

  • iovs_len: number

  • retptr0: number

  Returns number

fd_readdir

• fd_readdir(fd, buf, buf_len, cookie, retptr0): number

• Read directory entries from a directory. When successful, the contents of the output buffer consist of a sequence of directory entries. Each directory entry consists of a dirent object, followed by dirent::d_namlen bytes holding the name of the directory entry. This function fills the output buffer as much as possible, potentially truncating the last directory entry. This allows the caller to grow its read buffer size in case it's too small to fit a single large directory entry, or skip the oversized directory entry.

  Parameters

  • fd: number

  • buf: number

  • buf_len: number

  • cookie: bigint

  • retptr0: number

  Returns number

fd_renumber

• fd_renumber(old_fd, new_fd): number

• Atomically replace a file descriptor by renumbering another file descriptor. Due to the strong focus on thread safety, this environment does not provide a mechanism to duplicate or renumber a file descriptor to an arbitrary number, like dup2(). This would be prone to race conditions, as an actual file descriptor with the same number could be allocated by a different thread at the same time. This function provides a way to atomically renumber file descriptors, which would disappear if dup2() were to be removed entirely.

  Parameters

  • old_fd: number

  • new_fd: number

  Returns number

fd_seek

• fd_seek(fd, offset, whence, retptr0): Result

• Move the offset of a file descriptor.

  The offset is specified as a bigint here Note: This is similar to lseek in POSIX.

  The offset, and return type are FileSize (u64) which is represented by bigint in JavaScript.

  Parameters

  • fd: number

  • offset: bigint

  • whence: number

  • retptr0: number

  Returns Result

fd_sync

• fd_sync(fd): Result

• Synchronize the data and metadata of a file to disk. Note: This is similar to fsync in POSIX.

  Parameters

  • fd: number

  Returns Result

fd_tell

• fd_tell(fd, retptr0): number

• Return the current offset of a file descriptor. Note: This is similar to lseek(fd, 0, SEEK_CUR) in POSIX.

  The return type is FileSize (u64) which is represented by bigint in JS.

  Parameters

  • fd: number

  • retptr0: number

  Returns number

fd_write

• fd_write(fd, ciovs_ptr, ciovs_len, retptr0): number

• Write to a file descriptor. Note: This is similar to writev in POSIX.

  Parameters

  • fd: number

  • ciovs_ptr: number

  • ciovs_len: number

  • retptr0: number

  Returns number

getImportObject

• getImportObject(): {
      wasi_snapshot_preview1: ModuleImports & SnapshotPreview1;
      wasi_unstable: ModuleImports & SnapshotPreview1;
  }

• Returns {
      wasi_snapshot_preview1: ModuleImports & SnapshotPreview1;
      wasi_unstable: ModuleImports & SnapshotPreview1;
  }

  • wasi_snapshot_preview1: ModuleImports & SnapshotPreview1

  • wasi_unstable: ModuleImports & SnapshotPreview1

getImports

• getImports(version, debug?): ModuleImports & SnapshotPreview1

• Parameters

  • version: "unstable" | "preview1"

  • Optional debug: DebugFn

  Returns ModuleImports & SnapshotPreview1

initialize

• initialize(wasm, options?): void

• Initialize a WASI Reactor.

  See: https://github.com/WebAssembly/WASI/blob/main/legacy/application-abi.md

  Parameters

  • wasm: WebAssemblyInstantiatedSource

  • options: {
        memory?: Memory;
    } = {}

    • Optional memory?: Memory

  Returns void

path_create_directory

• path_create_directory(fd, path_ptr, path_len): number

• Create a directory. Note: This is similar to mkdirat in POSIX.

  Parameters

  • fd: number

  • path_ptr: number

  • path_len: number

  Returns number

path_filestat_get

• path_filestat_get(fd, flags, path_ptr, path_len, retptr0): number

• Parameters

  • fd: number

  • flags: number

  • path_ptr: number

  • path_len: number

  • retptr0: number

  Returns number

path_filestat_set_times

• path_filestat_set_times(fd, _, path_ptr, path_len, atim, mtim, fst_flags): number

• Adjust the timestamps of a file or directory. Note: This is similar to utimensat in POSIX.

  Parameters

  • fd: number

  • _: number

  • path_ptr: number

  • path_len: number

  • atim: bigint

  • mtim: bigint

  • fst_flags: number

  Returns number

path_link

• path_link(): Result

• Create a hard link. Note: This is similar to linkat in POSIX.

  Returns Result

path_open

• path_open(fd, _, path_ptr, path_len, oflags, rights_base, rights_inheriting, fdflags, retptr0): number

• Open a file or directory. The returned file descriptor is not guaranteed to be the lowest-numbered file descriptor not currently open; it is randomized to prevent applications from depending on making assumptions about indexes, since this is error-prone in multi-threaded contexts. The returned file descriptor is guaranteed to be less than 2**31. Note: This is similar to openat in POSIX.

  Parameters

  • fd: number

  • _: number

  • path_ptr: number

  • path_len: number

  • oflags: number

  • rights_base: bigint

  • rights_inheriting: bigint

  • fdflags: number

  • retptr0: number

  Returns number

path_readlink

• path_readlink(): Result

• Read the contents of a symbolic link. Note: This is similar to readlinkat in POSIX.

  Returns Result

path_remove_directory

• path_remove_directory(): Result

• Remove a directory. Return errno::notempty if the directory is not empty. Note: This is similar to unlinkat(fd, path, AT_REMOVEDIR) in POSIX.

  Returns Result

path_rename

• path_rename(old_fd_dir, old_path_ptr, old_path_len, new_fd_dir, new_path_ptr, new_path_len): number

• Rename a file or directory. Note: This is similar to renameat in POSIX.

  Parameters

  • old_fd_dir: number

  • old_path_ptr: number

  • old_path_len: number

  • new_fd_dir: number

  • new_path_ptr: number

  • new_path_len: number

  Returns number

path_symlink

• path_symlink(): Result

• Create a symbolic link. Note: This is similar to symlinkat in POSIX.

  Returns Result

path_unlink_file

• path_unlink_file(fd, path_ptr, path_len): number

• Unlink a file. Return errno::isdir if the path refers to a directory. Note: This is similar to unlinkat(fd, path, 0) in POSIX.

  Parameters

  • fd: number

  • path_ptr: number

  • path_len: number

  Returns number

poll_oneoff

• poll_oneoff(in_ptr, out_ptr, nsubscriptions, retptr0): number

• Concurrently poll for the occurrence of a set of events.

  Parameters

  • in_ptr: number

  • out_ptr: number

  • nsubscriptions: number

  • retptr0: number

  Returns number

proc_exit

• proc_exit(code): void

• Terminate the process normally. An exit code of 0 indicates successful termination of the program. The meanings of other values is dependent on the environment.

  Parameters

  • code: number

  Returns void

proc_raise

• proc_raise(): number

• Send a signal to the process of the calling thread. Note: This is similar to raise in POSIX.

  Returns number

random_get

• random_get(buffer_ptr, buffer_len): number

• Write high-quality random data into a buffer. This function blocks when the implementation is unable to immediately provide sufficient high-quality random data. This function may execute slowly, so when large mounts of random data are required, it's advisable to use this function to seed a pseudo-random number generator, rather than to provide the random data directly.

  Parameters

  • buffer_ptr: number

  • buffer_len: number

  Returns number

sched_yield

• sched_yield(): number

• Temporarily yield execution of the calling thread. Note: This is similar to sched_yield in POSIX.

  Returns number

shared_fd_filestat_get

• shared_fd_filestat_get(fd, retptr0, version): number

• Return the attributes of an open file.

  Parameters

  • fd: number

  • retptr0: number

  • version: "unstable" | "preview1"

  Returns number

shared_path_filestat_get

• shared_path_filestat_get(fd, _, path_ptr, path_len, retptr0, version): number

• Return the attributes of a file or directory. Note: This is similar to stat in POSIX.

  Parameters

  • fd: number

  • _: number

  • path_ptr: number

  • path_len: number

  • retptr0: number

  • version: "unstable" | "preview1"

  Returns number

sock_accept

• sock_accept(): number

• Accept a new incoming connection. Note: This is similar to accept in POSIX.

  Returns number

sock_bind

• sock_bind(): number

• Returns number

sock_connect

• sock_connect(): number

• Returns number

sock_getaddrinfo

• sock_getaddrinfo(): number

• Returns number

sock_getlocaladdr

• sock_getlocaladdr(): number

• Returns number

sock_getpeeraddr

• sock_getpeeraddr(): number

• Returns number

sock_listen

• sock_listen(): number

• Returns number

sock_open

• sock_open(): number

• Returns number

sock_recv

• sock_recv(): number

• Receive a message from a socket. Note: This is similar to recv in POSIX, though it also supports reading the data into multiple buffers in the manner of readv.

  Returns number

sock_send

• sock_send(): number

• Send a message on a socket. Note: This is similar to send in POSIX, though it also supports writing the data from multiple buffers in the manner of writev.

  Returns number

sock_setsockopt

• sock_setsockopt(): number

• Returns number

sock_shutdown

• sock_shutdown(): number

• Shut down socket send and receive channels. Note: This is similar to shutdown in POSIX.

  Returns number

start

• start(wasm, options?): WASIExecutionResult

• Start a WASI command.

  See: https://github.com/WebAssembly/WASI/blob/main/legacy/application-abi.md

  Parameters

  • wasm: WebAssemblyInstantiatedSource

  • options: {
        memory?: Memory;
    } = {}

    • Optional memory?: Memory

  Returns WASIExecutionResult

unstable_fd_filestat_get

• unstable_fd_filestat_get(fd, retptr0): number

• Return the attributes of an open file. This version is used

  Parameters

  • fd: number

  • retptr0: number

  Returns number

unstable_fd_seek

• unstable_fd_seek(fd, offset, whence, retptr0): Result

• Parameters

  • fd: number

  • offset: bigint

  • whence: number

  • retptr0: number

  Returns Result

unstable_path_filestat_get

• unstable_path_filestat_get(fd, flags, path_ptr, path_len, retptr0): number

• Parameters

  • fd: number

  • flags: number

  • path_ptr: number

  • path_len: number

  • retptr0: number

  Returns number

Static initialize

• initialize(wasmSource, context?): Promise<Exports>

• Initialize a WASI reactor.

  Returns the WebAssembly instance exports.

  Parameters

  • wasmSource: Response | PromiseLike<Response>

  • context: Partial<WASIContextOptions> = {}

  Returns Promise<Exports>

Static start

• start(wasmSource, context?): Promise<WASIExecutionResult>

• Start a WASI command.

  Parameters

  • wasmSource: Response | PromiseLike<Response>

  • context: Partial<WASIContextOptions> = {}

  Returns Promise<WASIExecutionResult>