From d52afb7f1a9c730efbd543f5906a4d5ea9c147c3 Mon Sep 17 00:00:00 2001 From: Guy Bedford Date: Wed, 20 Mar 2024 11:10:10 -0700 Subject: [PATCH 1/2] add poll.check --- imports.md | 12 ++++++++++++ wit/poll.wit | 12 ++++++++++++ 2 files changed, 24 insertions(+) diff --git a/imports.md b/imports.md index 1ae5b12..354051f 100644 --- a/imports.md +++ b/imports.md @@ -93,6 +93,18 @@ being reaedy for I/O.

+

check: func

+

Check for readiness on a set of pollables.

+

Identical to poll, in taking a list of pollables and returning a list<u32> of handles in the argument list that are ready for I/O, but instead of blocking on at least one pollable in the list to be ready, this function immediately returns and may return an empty list if no pollables are currently ready.

+

If the list contains more elements than can be indexed with a u32 value, this function traps.

+
Params
+ +
Return values
+

Import interface wasi:io/streams@0.2.0

WASI I/O is an I/O abstraction API which is currently focused on providing stream types.

diff --git a/wit/poll.wit b/wit/poll.wit index ddc67f8..779751d 100644 --- a/wit/poll.wit +++ b/wit/poll.wit @@ -38,4 +38,16 @@ interface poll { /// the pollables has an error, it is indicated by marking the source as /// being reaedy for I/O. poll: func(in: list>) -> list; + + /// Check for readiness on a set of pollables. + /// + /// Identical to poll, in taking a list of pollables and returning a + /// `list` of handles in the argument list that are ready for I/O, but + /// instead of blocking on at least one pollable in the list to be ready, + /// this function immediately returns and may return an empty list if no + /// pollables are currently ready. + /// + /// If the list contains more elements than can be indexed with a `u32` + /// value, this function traps. + check: func(in: list>) -> list; } From fda14df72fb43f2231314c4850864133583b88c3 Mon Sep 17 00:00:00 2001 From: Guy Bedford Date: Wed, 20 Mar 2024 15:24:40 -0700 Subject: [PATCH 2/2] fixup imports --- imports.md | 139 +++++++++++++++++++++++++++-------------------------- 1 file changed, 72 insertions(+), 67 deletions(-) diff --git a/imports.md b/imports.md index 354051f..60ceeaa 100644 --- a/imports.md +++ b/imports.md @@ -8,10 +8,10 @@ -

Import interface wasi:io/error@0.2.0

+

Import interface wasi:io/error@0.2.0

Types

-

resource error

+

resource error

A 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.

@@ -28,7 +28,7 @@ error-code type, using the function

The set of functions which can "downcast" an error into a more concrete type is open.

Functions

-

[method]error.to-debug-string: func

+

[method]error.to-debug-string: func

Returns a string that is suitable to assist humans in debugging this error.

WARNING: The returned string should not be consumed mechanically! @@ -37,41 +37,41 @@ details. Parsing this string is a major platform-compatibility hazard.

Params
Return values
  • string
-

Import interface wasi:io/poll@0.2.0

+

Import interface wasi:io/poll@0.2.0

A poll API intended to let users wait for I/O events on multiple handles at once.

Types

-

resource pollable

+

resource pollable

pollable represents a single I/O event which may be ready, or not.

Functions

-

[method]pollable.ready: func

+

[method]pollable.ready: func

Return the readiness of a pollable. This function never blocks.

Returns true when the pollable is ready, and false otherwise.

Params
Return values
  • bool
-

[method]pollable.block: func

+

[method]pollable.block: func

block 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.

Params
-

poll: func

+

poll: func

Poll 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.

@@ -87,54 +87,59 @@ the pollables has an error, it is indicated by marking the source as being reaedy for I/O.

Params
Return values
  • list<u32>
-

check: func

+

check: func

Check for readiness on a set of pollables.

-

Identical to poll, in taking a list of pollables and returning a list<u32> of handles in the argument list that are ready for I/O, but instead of blocking on at least one pollable in the list to be ready, this function immediately returns and may return an empty list if no pollables are currently ready.

-

If the list contains more elements than can be indexed with a u32 value, this function traps.

+

Identical to poll, in taking a list of pollables and returning a +list<u32> of handles in the argument list that are ready for I/O, but +instead of blocking on at least one pollable in the list to be ready, +this function immediately returns and may return an empty list if no +pollables are currently ready.

+

If the list contains more elements than can be indexed with a u32 +value, this function traps.

Params
Return values
    -
  • list<u32>
    • +
  • list<u32>
-

Import interface wasi:io/streams@0.2.0

+

Import interface wasi:io/streams@0.2.0

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.

Types

-

type error

+

type error

error

-#### `type pollable` +#### `type pollable` [`pollable`](#pollable)

-#### `variant stream-error` +#### `variant stream-error`

An error for input-stream and output-stream operations.

Variant Cases
  • -

    last-operation-failed: own<error>

    +

    last-operation-failed: own<error>

    The last operation (a write or flush) failed before completion.

    More information is available in the error payload.

  • -

    closed

    +

    closed

    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-stream

+

resource input-stream

An input bytestream.

input-streams are non-blocking to the extent practical on underlying platforms. I/O operations always return promptly; if fewer bytes are @@ -142,7 +147,7 @@ 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-stream

+

resource output-stream

An output bytestream.

output-streams are non-blocking to the extent practical on underlying platforms. Except where specified otherwise, I/O operations also @@ -151,7 +156,7 @@ 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.

Functions

-

[method]input-stream.read: func

+

[method]input-stream.read: func

Perform 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 @@ -175,51 +180,51 @@ 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.

Params
Return values
-

[method]input-stream.blocking-read: func

+

[method]input-stream.blocking-read: func

Read bytes from a stream, after blocking until at least one byte can be read. Except for blocking, behavior is identical to read.

Params
Return values
-

[method]input-stream.skip: func

+

[method]input-stream.skip: func

Skip 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.

Params
Return values
-

[method]input-stream.blocking-skip: func

+

[method]input-stream.blocking-skip: func

Skip bytes from a stream, after blocking until at least one byte can be skipped. Except for blocking behavior, identical to skip.

Params
Return values
-

[method]input-stream.subscribe: func

+

[method]input-stream.subscribe: func

Create 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. @@ -228,13 +233,13 @@ Implementations may trap if the input-streampollables created with this function are dropped.

Params
Return values
-

[method]output-stream.check-write: func

+

[method]output-stream.check-write: func

Check 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 @@ -244,13 +249,13 @@ become ready when this function will report at least 1 byte, or an error.

Params
Return values
-

[method]output-stream.write: func

+

[method]output-stream.write: func

Perform 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 @@ -263,14 +268,14 @@ length of less than or equal to n. Otherwise, this function will trap.

the last call to check-write provided a permit.

Params
Return values
-

[method]output-stream.blocking-write-and-flush: func

+

[method]output-stream.blocking-write-and-flush: func

Perform 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, @@ -294,14 +299,14 @@ let _ = this.check-write(); // eliding error handling

Params
Return values
-

[method]output-stream.flush: func

+

[method]output-stream.flush: func

Request 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 @@ -312,24 +317,24 @@ completed. The subscribe pollable will become ready when the flush has completed and the stream can accept more writes.

Params
Return values
-

[method]output-stream.blocking-flush: func

+

[method]output-stream.blocking-flush: func

Request to flush buffered output, and block until flush completes and stream is ready for writing again.

Params
Return values
-

[method]output-stream.subscribe: func

+

[method]output-stream.subscribe: func

Create 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 @@ -340,13 +345,13 @@ Implementations may trap if the output-streampollables created with this function are dropped.

Params
Return values
-

[method]output-stream.write-zeroes: func

+

[method]output-stream.write-zeroes: func

Write zeroes to a stream.

This should be used precisely like write with the exact same preconditions (must use check-write first), but instead of @@ -354,14 +359,14 @@ passing a list of bytes, you simply pass the number of zero-bytes that should be written.

Params
Return values
-

[method]output-stream.blocking-write-zeroes-and-flush: func

+

[method]output-stream.blocking-write-zeroes-and-flush: func

Perform a write of up to 4096 zeroes, and then flush the stream. Block until all of these operations are complete, or an error occurs.

@@ -385,14 +390,14 @@ let _ = this.check-write(); // eliding error handling
Params
Return values
-

[method]output-stream.splice: func

+

[method]output-stream.splice: func

Read from one stream and write to another.

The behavior of splice is equivelant to:

    @@ -407,24 +412,24 @@ let _ = this.check-write(); // eliding error handling than len.

    Params
    Return values
    -

    [method]output-stream.blocking-splice: func

    +

    [method]output-stream.blocking-splice: func

    Read 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.

    Params
    Return values