wasi:io/error@0.2.0wasi:io/poll@0.2.0wasi:io/streams@0.2.0wasi:clocks/wall-clock@0.2.0wasi:filesystem/types@0.2.0wasi:filesystem/preopens@0.2.0resource errorA resource which represents some error information.
The only method provided by this resource is to-debug-string,
which provides some human-readable information about the error.
In the wasi:io package, this resource is returned through the
wasi:io/streams/stream-error type.
To provide more specific error information, other interfaces may
provide functions to further "downcast" this error into more specific
error information. For example, errors returned in streams derived
from filesystem types to be described using the filesystem's own
error-code type, using the function
wasi:filesystem/types/filesystem-error-code, which takes a parameter
borrow<error> and returns
option<wasi:filesystem/types/error-code>.
error into a more
concrete type is open.[method]error.to-debug-string: funcReturns a string that is suitable to assist humans in debugging this error.
WARNING: The returned string should not be consumed mechanically! It may change across platforms, hosts, or other implementation details. Parsing this string is a major platform-compatibility hazard.
A poll API intended to let users wait for I/O events on multiple handles at once.
resource pollablepollable represents a single I/O event which may be ready, or not.[method]pollable.ready: funcReturn the readiness of a pollable. This function never blocks.
Returns true when the pollable is ready, and false otherwise.
[method]pollable.block: funcblock returns immediately if the pollable is ready, and otherwise
blocks until ready.
This function is equivalent to calling poll.poll on a list
containing only this pollable.
poll: funcPoll for completion on a set of pollables.
This function takes a list of pollables, which identify I/O sources of interest, and waits until one or more of the events is ready for I/O.
The result list<u32> contains one or more indices of handles in the
argument list that is ready for I/O.
If the list contains more elements than can be indexed with a u32
value, this function traps.
A timeout can be implemented by adding a pollable from the wasi-clocks API to the list.
This function does not return a result; polling in itself does not
do any I/O so it doesn't fail. If any of the I/O sources identified by
the pollables has an error, it is indicated by marking the source as
being reaedy for I/O.
WASI I/O is an I/O abstraction API which is currently focused on providing stream types.
In the future, the component model is expected to add built-in stream types; when it does, they are expected to subsume this API.
type error#### `type pollable` [`pollable`](#pollable)
An error for input-stream and output-stream operations.
last-operation-failed: own<error>
The last operation (a write or flush) failed before completion.
More information is available in the error payload.
The stream is closed: no more input will be accepted by the stream. A closed output-stream will return this error on all future operations.
resource input-streamAn input bytestream.
input-streams are non-blocking to the extent practical on underlying
platforms. I/O operations always return promptly; if fewer bytes are
promptly available than requested, they return the number of bytes promptly
available, which could even be zero. To wait for data to be available,
use the subscribe function to obtain a pollable which can be polled
for using wasi:io/poll.
resource output-streamAn output bytestream.
output-streams are non-blocking to the extent practical on
underlying platforms. Except where specified otherwise, I/O operations also
always return promptly, after the number of bytes that can be written
promptly, which could even be zero. To wait for the stream to be ready to
accept data, the subscribe function to obtain a pollable which can be
polled for using wasi:io/poll.[method]input-stream.read: funcPerform a non-blocking read from the stream.
When the source of a read is binary data, the bytes from the source
are returned verbatim. When the source of a read is known to the
implementation to be text, bytes containing the UTF-8 encoding of the
text are returned.
This function returns a list of bytes containing the read data,
when successful. The returned list will contain up to len bytes;
it may return fewer than requested, but not more. The list is
empty when no bytes are available for reading at this time. The
pollable given by subscribe will be ready when more bytes are
available.
This function fails with a stream-error when the operation
encounters an error, giving last-operation-failed, or when the
stream is closed, giving closed.
When the caller gives a len of 0, it represents a request to
read 0 bytes. If the stream is still open, this call should
succeed and return an empty list, or otherwise fail with closed.
The len parameter is a u64, which could represent a list of u8 which
is not possible to allocate in wasm32, or not desirable to allocate as
as a return value by the callee. The callee may return a list of bytes
less than len in size while more bytes are available for reading.
self: borrow<input-stream>len: u64u8>, stream-error>[method]input-stream.blocking-read: funcRead bytes from a stream, after blocking until at least one byte can
be read. Except for blocking, behavior is identical to read.
self: borrow<input-stream>len: u64u8>, stream-error>[method]input-stream.skip: funcSkip bytes from a stream. Returns number of bytes skipped.
Behaves identical to read, except instead of returning a list
of bytes, returns the number of bytes consumed from the stream.
self: borrow<input-stream>len: u64u64, stream-error>[method]input-stream.blocking-skip: funcSkip bytes from a stream, after blocking until at least one byte
can be skipped. Except for blocking behavior, identical to skip.
self: borrow<input-stream>len: u64u64, stream-error>[method]input-stream.subscribe: funcCreate a pollable which will resolve once either the specified stream
has bytes available to read or the other end of the stream has been
closed.
The created pollable is a child resource of the input-stream.
Implementations may trap if the input-stream is dropped before
all derived pollables created with this function are dropped.
self: borrow<input-stream>pollable>[method]output-stream.check-write: funcCheck readiness for writing. This function never blocks.
Returns the number of bytes permitted for the next call to write,
or an error. Calling write with more bytes than this function has
permitted will trap.
When this function returns 0 bytes, the subscribe pollable will
become ready when this function will report at least 1 byte, or an
error.
self: borrow<output-stream>u64, stream-error>[method]output-stream.write: funcPerform a write. This function never blocks.
When the destination of a write is binary data, the bytes from
contents are written verbatim. When the destination of a write is
known to the implementation to be text, the bytes of contents are
transcoded from UTF-8 into the encoding of the destination and then
written.
Precondition: check-write gave permit of Ok(n) and contents has a length of less than or equal to n. Otherwise, this function will trap.
returns Err(closed) without writing if the stream has closed since the last call to check-write provided a permit.
self: borrow<output-stream>contents: list<u8>stream-error>[method]output-stream.blocking-write-and-flush: funcPerform a write of up to 4096 bytes, and then flush the stream. Block until all of these operations are complete, or an error occurs.
This is a convenience wrapper around the use of check-write,
subscribe, write, and flush, and is implemented with the
following pseudo-code:
let pollable = this.subscribe();
while !contents.is_empty() {
// Wait for the stream to become writable
pollable.block();
let Ok(n) = this.check-write(); // eliding error handling
let len = min(n, contents.len());
let (chunk, rest) = contents.split_at(len);
this.write(chunk ); // eliding error handling
contents = rest;
}
this.flush();
// Wait for completion of `flush`
pollable.block();
// Check for any errors that arose during `flush`
let _ = this.check-write(); // eliding error handling
self: borrow<output-stream>contents: list<u8>stream-error>[method]output-stream.flush: funcRequest to flush buffered output. This function never blocks.
This tells the output-stream that the caller intends any buffered
output to be flushed. the output which is expected to be flushed
is all that has been passed to write prior to this call.
Upon calling this function, the output-stream will not accept any
writes (check-write will return ok(0)) until the flush has
completed. The subscribe pollable will become ready when the
flush has completed and the stream can accept more writes.
self: borrow<output-stream>stream-error>[method]output-stream.blocking-flush: funcRequest to flush buffered output, and block until flush completes and stream is ready for writing again.
self: borrow<output-stream>stream-error>[method]output-stream.subscribe: funcCreate a pollable which will resolve once the output-stream
is ready for more writing, or an error has occured. When this
pollable is ready, check-write will return ok(n) with n>0, or an
error.
If the stream is closed, this pollable is always ready immediately.
The created pollable is a child resource of the output-stream.
Implementations may trap if the output-stream is dropped before
all derived pollables created with this function are dropped.
self: borrow<output-stream>pollable>[method]output-stream.write-zeroes: funcWrite zeroes to a stream.
This should be used precisely like write with the exact same
preconditions (must use check-write first), but instead of
passing a list of bytes, you simply pass the number of zero-bytes
that should be written.
self: borrow<output-stream>len: u64stream-error>[method]output-stream.blocking-write-zeroes-and-flush: funcPerform a write of up to 4096 zeroes, and then flush the stream. Block until all of these operations are complete, or an error occurs.
This is a convenience wrapper around the use of check-write,
subscribe, write-zeroes, and flush, and is implemented with
the following pseudo-code:
let pollable = this.subscribe();
while num_zeroes != 0 {
// Wait for the stream to become writable
pollable.block();
let Ok(n) = this.check-write(); // eliding error handling
let len = min(n, num_zeroes);
this.write-zeroes(len); // eliding error handling
num_zeroes -= len;
}
this.flush();
// Wait for completion of `flush`
pollable.block();
// Check for any errors that arose during `flush`
let _ = this.check-write(); // eliding error handling
self: borrow<output-stream>len: u64stream-error>[method]output-stream.splice: funcRead from one stream and write to another.
The behavior of splice is equivelant to:
check-write on the output-streamread on the input-stream with the smaller of the
check-write permitted length and the len provided to splicewrite on the output-stream with that read data.Any error reported by the call to check-write, read, or
write ends the splice and reports that error.
This function returns the number of bytes transferred; it may be less
than len.
self: borrow<output-stream>src: borrow<input-stream>len: u64u64, stream-error>[method]output-stream.blocking-splice: funcRead from one stream and write to another, with blocking.
This is similar to splice, except that it blocks until the
output-stream is ready for writing, and the input-stream
is ready for reading, before performing the splice.
self: borrow<output-stream>src: borrow<input-stream>len: u64u64, stream-error>WASI Wall Clock is a clock API intended to let users query the current time. The name "wall" makes an analogy to a "clock on the wall", which is not necessarily monotonic as it may be reset.
It is intended to be portable at least between Unix-family platforms and Windows.
A wall clock is a clock which measures the date and time according to some external reference.
External references may be reset, so this clock is not necessarily monotonic, making it unsuitable for measuring elapsed time.
It is intended for reporting the current date and time for humans.
record datetimeA time and date in seconds plus nanoseconds.
seconds: u64nanoseconds: u32now: funcRead the current value of the clock.
This clock is not monotonic, therefore calling this function repeatedly will not necessarily produce a sequence of non-decreasing values.
The returned timestamps represent the number of seconds since 1970-01-01T00:00:00Z, also known as POSIX's Seconds Since the Epoch, also known as Unix Time.
The nanoseconds field of the output is always less than 1000000000.
resolution: funcQuery the resolution of the clock.
The nanoseconds field of the output is always less than 1000000000.
WASI filesystem is a filesystem API primarily intended to let users run WASI programs that access their files on their existing filesystems, without significant overhead.
It is intended to be roughly portable between Unix-family platforms and Windows, though it does not hide many of the major differences.
Paths are passed as interface-type strings, meaning they must consist of
a sequence of Unicode Scalar Values (USVs). Some filesystems may contain
paths which are not accessible by this API.
The directory separator in WASI is always the forward-slash (/).
All paths in WASI are relative paths, and are interpreted relative to a
descriptor referring to a base directory. If a path argument to any WASI
function starts with /, or if any step of resolving a path, including
.. and symbolic link steps, reaches a directory outside of the base
directory, or reaches a symlink to an absolute or rooted path in the
underlying filesystem, the function fails with error-code::not-permitted.
For more information about WASI path resolution and sandboxing, see WASI filesystem path resolution.
type input-stream#### `type output-stream` [`output-stream`](#output_stream)
#### `type error` [`error`](#error)
#### `type datetime` [`datetime`](#datetime)
#### `type filesize` `u64`
File size or length of a region within a file.
enum descriptor-typeThe type of a filesystem object referenced by a descriptor.
Note: This was called filetype in earlier versions of WASI.
The type of the descriptor or file is unknown or is different from any of the other types specified.
The descriptor refers to a block device inode.
The descriptor refers to a character device inode.
The descriptor refers to a directory inode.
The descriptor refers to a named pipe.
The file refers to a symbolic link inode.
The descriptor refers to a regular file inode.
The descriptor refers to a socket.
flags descriptor-flagsDescriptor flags.
Note: This was called fdflags in earlier versions of WASI.
read:
Read mode: Data can be read.
Write mode: Data can be written to.
Request that writes be performed according to synchronized I/O file integrity completion. The data stored in the file and the file's metadata are synchronized. This is similar to `O_SYNC` in POSIX.
The precise semantics of this operation have not yet been defined for WASI. At this time, it should be interpreted as a request, and not a requirement.
Request that writes be performed according to synchronized I/O data integrity completion. Only the data stored in the file is synchronized. This is similar to `O_DSYNC` in POSIX.
The precise semantics of this operation have not yet been defined for WASI. At this time, it should be interpreted as a request, and not a requirement.
Requests that reads be performed at the same level of integrety requested for writes. This is similar to `O_RSYNC` in POSIX.
The precise semantics of this operation have not yet been defined for WASI. At this time, it should be interpreted as a request, and not a requirement.
Mutating directories mode: Directory contents may be mutated.
When this flag is unset on a descriptor, operations using the
descriptor which would create, rename, delete, modify the data or
metadata of filesystem objects, or obtain another handle which
would permit any of those, shall fail with error-code::read-only if
they would otherwise succeed.
This may only be set on directories.
flags path-flagsFlags determining the method of how paths are resolved.
symlink-follow: As long as the resolved path corresponds to a symbolic link, it is expanded.
flags open-flagsOpen flags used by open-at.
Create file if it does not exist, similar to `O_CREAT` in POSIX.
Fail if not a directory, similar to `O_DIRECTORY` in POSIX.
Fail if file already exists, similar to `O_EXCL` in POSIX.
Truncate file to size 0, similar to `O_TRUNC` in POSIX.
type link-countu64
Number of hard links to an inode.
record descriptor-statFile attributes.
Note: This was called filestat in earlier versions of WASI.
File type.
Number of hard links to the file.
For regular files, the file size in bytes. For symbolic links, the length in bytes of the pathname contained in the symbolic link.
data-access-timestamp: option<datetime>
Last data access timestamp.
If the option is none, the platform doesn't maintain an access
timestamp for this file.
data-modification-timestamp: option<datetime>
Last data modification timestamp.
If the option is none, the platform doesn't maintain a
modification timestamp for this file.
status-change-timestamp: option<datetime>
Last file status-change timestamp.
If the option is none, the platform doesn't maintain a
status-change timestamp for this file.
variant new-timestampWhen setting a timestamp, this gives the value to set it to.
Leave the timestamp set to its previous value.
Set the timestamp to the current time of the system clock associated with the filesystem.
Set the timestamp to the given value.
record directory-entryA directory entry.
The type of the file referred to by this directory entry.
name: string
The name of the object.
enum error-codeError codes returned by functions, similar to errno in POSIX.
Not all of these error codes are returned by the functions provided by this
API; some are used in higher-level library layers, and others are provided
merely for alignment with POSIX.
Permission denied, similar to `EACCES` in POSIX.
Resource unavailable, or operation would block, similar to `EAGAIN` and `EWOULDBLOCK` in POSIX.
Connection already in progress, similar to `EALREADY` in POSIX.
Bad descriptor, similar to `EBADF` in POSIX.
Device or resource busy, similar to `EBUSY` in POSIX.
Resource deadlock would occur, similar to `EDEADLK` in POSIX.
Storage quota exceeded, similar to `EDQUOT` in POSIX.
File exists, similar to `EEXIST` in POSIX.
File too large, similar to `EFBIG` in POSIX.
Illegal byte sequence, similar to `EILSEQ` in POSIX.
Operation in progress, similar to `EINPROGRESS` in POSIX.
Interrupted function, similar to `EINTR` in POSIX.
Invalid argument, similar to `EINVAL` in POSIX.
I/O error, similar to `EIO` in POSIX.
Is a directory, similar to `EISDIR` in POSIX.
Too many levels of symbolic links, similar to `ELOOP` in POSIX.
Too many links, similar to `EMLINK` in POSIX.
Message too large, similar to `EMSGSIZE` in POSIX.
Filename too long, similar to `ENAMETOOLONG` in POSIX.
No such device, similar to `ENODEV` in POSIX.
No such file or directory, similar to `ENOENT` in POSIX.
No locks available, similar to `ENOLCK` in POSIX.
Not enough space, similar to `ENOMEM` in POSIX.
No space left on device, similar to `ENOSPC` in POSIX.
Not a directory or a symbolic link to a directory, similar to `ENOTDIR` in POSIX.
Directory not empty, similar to `ENOTEMPTY` in POSIX.
State not recoverable, similar to `ENOTRECOVERABLE` in POSIX.
Not supported, similar to `ENOTSUP` and `ENOSYS` in POSIX.
Inappropriate I/O control operation, similar to `ENOTTY` in POSIX.
No such device or address, similar to `ENXIO` in POSIX.
Value too large to be stored in data type, similar to `EOVERFLOW` in POSIX.
Operation not permitted, similar to `EPERM` in POSIX.
Broken pipe, similar to `EPIPE` in POSIX.
Read-only file system, similar to `EROFS` in POSIX.
Invalid seek, similar to `ESPIPE` in POSIX.
Text file busy, similar to `ETXTBSY` in POSIX.
Cross-device link, similar to `EXDEV` in POSIX.
enum adviceFile or memory access pattern advisory information.
The application has no advice to give on its behavior with respect to the specified data.
The application expects to access the specified data sequentially from lower offsets to higher offsets.
The application expects to access the specified data in a random order.
The application expects to access the specified data in the near future.
The application expects that it will not access the specified data in the near future.
The application expects to access the specified data once and then not reuse it thereafter.
record metadata-hash-valueA 128-bit hash value, split into parts because wasm doesn't have a 128-bit integer type.
resource descriptorA descriptor is a reference to a filesystem object, which may be a file, directory, named pipe, special file, or other object on which filesystem calls may be made.
resource directory-entry-stream[method]descriptor.read-via-stream: funcReturn a stream for reading from a file, if available.
May fail with an error-code describing why the file cannot be read.
Multiple read, write, and append streams may be active on the same open file and they do not interfere with each other.
Note: This allows using read-stream, which is similar to read in POSIX.
self: borrow<descriptor>offset: filesizeinput-stream>, error-code>[method]descriptor.write-via-stream: funcReturn a stream for writing to a file, if available.
May fail with an error-code describing why the file cannot be written.
Note: This allows using write-stream, which is similar to write in
POSIX.
self: borrow<descriptor>offset: filesizeoutput-stream>, error-code>[method]descriptor.append-via-stream: funcReturn a stream for appending to a file, if available.
May fail with an error-code describing why the file cannot be appended.
Note: This allows using write-stream, which is similar to write with
O_APPEND in in POSIX.
self: borrow<descriptor>output-stream>, error-code>[method]descriptor.advise: funcProvide file advisory information on a descriptor.
This is similar to posix_fadvise in POSIX.
error-code>[method]descriptor.sync-data: funcSynchronize the data of a file to disk.
This function succeeds with no effect if the file descriptor is not opened for writing.
Note: This is similar to fdatasync in POSIX.
self: borrow<descriptor>error-code>[method]descriptor.get-flags: funcGet flags associated with a descriptor.
Note: This returns similar flags to fcntl(fd, F_GETFL) in POSIX.
Note: This returns the value that was the fs_flags value returned
from fdstat_get in earlier versions of WASI.
self: borrow<descriptor>descriptor-flags, error-code>[method]descriptor.get-type: funcGet the dynamic type of a descriptor.
Note: This returns the same value as the type field of the fd-stat
returned by stat, stat-at and similar.
Note: This returns similar flags to the st_mode & S_IFMT value provided
by fstat in POSIX.
Note: This returns the value that was the fs_filetype value returned
from fdstat_get in earlier versions of WASI.
self: borrow<descriptor>descriptor-type, error-code>[method]descriptor.set-size: funcAdjust the size of an open file. If this increases the file's size, the extra bytes are filled with zeros.
Note: This was called fd_filestat_set_size in earlier versions of WASI.
self: borrow<descriptor>size: filesizeerror-code>[method]descriptor.set-times: funcAdjust the timestamps of an open file or directory.
Note: This is similar to futimens in POSIX.
Note: This was called fd_filestat_set_times in earlier versions of WASI.
self: borrow<descriptor>data-access-timestamp: new-timestampdata-modification-timestamp: new-timestamperror-code>[method]descriptor.read: funcRead from a descriptor, without using and updating the descriptor's offset.
This function returns a list of bytes containing the data that was
read, along with a bool which, when true, indicates that the end of the
file was reached. The returned list will contain up to length bytes; it
may return fewer than requested, if the end of the file is reached or
if the I/O operation is interrupted.
In the future, this may change to return a stream<u8, error-code>.
Note: This is similar to pread in POSIX.
u8>, bool), error-code>[method]descriptor.write: funcWrite to a descriptor, without using and updating the descriptor's offset.
It is valid to write past the end of a file; the file is extended to the extent of the write, with bytes between the previous end and the start of the write set to zero.
In the future, this may change to take a stream<u8, error-code>.
Note: This is similar to pwrite in POSIX.
self: borrow<descriptor>buffer: list<u8>offset: filesizefilesize, error-code>[method]descriptor.read-directory: funcRead directory entries from a directory.
On filesystems where directories contain entries referring to themselves
and their parents, often named . and .. respectively, these entries
are omitted.
This always returns a new stream which starts at the beginning of the directory. Multiple streams may be active on the same directory, and they do not interfere with each other.
self: borrow<descriptor>directory-entry-stream>, error-code>[method]descriptor.sync: funcSynchronize the data and metadata of a file to disk.
This function succeeds with no effect if the file descriptor is not opened for writing.
Note: This is similar to fsync in POSIX.
self: borrow<descriptor>error-code>[method]descriptor.create-directory-at: funcCreate a directory.
Note: This is similar to mkdirat in POSIX.
self: borrow<descriptor>path: stringerror-code>[method]descriptor.stat: funcReturn the attributes of an open file or directory.
Note: This is similar to fstat in POSIX, except that it does not return
device and inode information. For testing whether two descriptors refer to
the same underlying filesystem object, use is-same-object. To obtain
additional data that can be used do determine whether a file has been
modified, use metadata-hash.
Note: This was called fd_filestat_get in earlier versions of WASI.
self: borrow<descriptor>descriptor-stat, error-code>[method]descriptor.stat-at: funcReturn the attributes of a file or directory.
Note: This is similar to fstatat in POSIX, except that it does not
return device and inode information. See the stat description for a
discussion of alternatives.
Note: This was called path_filestat_get in earlier versions of WASI.
self: borrow<descriptor>path-flags: path-flagspath: stringdescriptor-stat, error-code>[method]descriptor.set-times-at: funcAdjust the timestamps of a file or directory.
Note: This is similar to utimensat in POSIX.
Note: This was called path_filestat_set_times in earlier versions of
WASI.
self: borrow<descriptor>path-flags: path-flagspath: stringdata-access-timestamp: new-timestampdata-modification-timestamp: new-timestamperror-code>[method]descriptor.link-at: funcCreate a hard link.
Note: This is similar to linkat in POSIX.
self: borrow<descriptor>old-path-flags: path-flagsold-path: stringnew-descriptor: borrow<descriptor>new-path: stringerror-code>[method]descriptor.open-at: funcOpen a file or directory.
The returned descriptor is not guaranteed to be the lowest-numbered 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 descriptor is guaranteed to be less than 2**31.
If flags contains descriptor-flags::mutate-directory, and the base
descriptor doesn't have descriptor-flags::mutate-directory set,
open-at fails with error-code::read-only.
If flags contains write or mutate-directory, or open-flags
contains truncate or create, and the base descriptor doesn't have
descriptor-flags::mutate-directory set, open-at fails with
error-code::read-only.
Note: This is similar to openat in POSIX.
self: borrow<descriptor>path-flags: path-flagspath: stringopen-flags: open-flagsflags: descriptor-flagsdescriptor>, error-code>[method]descriptor.readlink-at: funcRead the contents of a symbolic link.
If the contents contain an absolute or rooted path in the underlying
filesystem, this function fails with error-code::not-permitted.
Note: This is similar to readlinkat in POSIX.
self: borrow<descriptor>path: stringstring, error-code>[method]descriptor.remove-directory-at: funcRemove a directory.
Return error-code::not-empty if the directory is not empty.
Note: This is similar to unlinkat(fd, path, AT_REMOVEDIR) in POSIX.
self: borrow<descriptor>path: stringerror-code>[method]descriptor.rename-at: funcRename a filesystem object.
Note: This is similar to renameat in POSIX.
self: borrow<descriptor>old-path: stringnew-descriptor: borrow<descriptor>new-path: stringerror-code>[method]descriptor.symlink-at: funcCreate a symbolic link (also known as a "symlink").
If old-path starts with /, the function fails with
error-code::not-permitted.
Note: This is similar to symlinkat in POSIX.
self: borrow<descriptor>old-path: stringnew-path: stringerror-code>[method]descriptor.unlink-file-at: funcUnlink a filesystem object that is not a directory.
Return error-code::is-directory if the path refers to a directory.
Note: This is similar to unlinkat(fd, path, 0) in POSIX.
self: borrow<descriptor>path: stringerror-code>[method]descriptor.is-same-object: funcTest whether two descriptors refer to the same filesystem object.
In POSIX, this corresponds to testing whether the two descriptors have the
same device (st_dev) and inode (st_ino or d_ino) numbers.
wasi-filesystem does not expose device and inode numbers, so this function
may be used instead.
self: borrow<descriptor>other: borrow<descriptor>[method]descriptor.metadata-hash: funcReturn a hash of the metadata associated with a filesystem object referred to by a descriptor.
This returns a hash of the last-modification timestamp and file size, and may also include the inode number, device number, birth timestamp, and other metadata fields that may change when the file is modified or replaced. It may also include a secret value chosen by the implementation and not otherwise exposed.
Implementations are encourated to provide the following properties:
However, none of these is required.
self: borrow<descriptor>metadata-hash-value, error-code>[method]descriptor.metadata-hash-at: funcReturn a hash of the metadata associated with a filesystem object referred to by a directory descriptor and a relative path.
This performs the same hash computation as metadata-hash.
self: borrow<descriptor>path-flags: path-flagspath: stringmetadata-hash-value, error-code>[method]directory-entry-stream.read-directory-entry: funcRead a single directory entry from a directory-entry-stream.
self: borrow<directory-entry-stream>directory-entry>, error-code>filesystem-error-code: funcAttempts to extract a filesystem-related error-code from the stream
error provided.
Stream operations which return stream-error::last-operation-failed
have a payload with more information about the operation that failed.
This payload can be passed through to this function to see if there's
filesystem-related information about the error to return.
Note that this function is fallible because not all stream-related errors are filesystem-related errors.
error-code>type descriptor----
get-directories: funcReturn the set of preopened directories, and their path.
descriptor>, string)>