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103 lines
4.2 KiB
C
103 lines
4.2 KiB
C
// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include <app/file.h>
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#include <app/instance.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <tactility/concurrent/mutex.h>
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#include <tactility/concurrent/task_event_group.h>
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#include <tactility/error.h>
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#include <tactility/freertos/freertos.h>
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#include <tactility/freertos/task.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct AppStreamBuffer {
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uint8_t* data;
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size_t capacity;
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size_t read_pos;
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size_t write_pos;
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size_t count;
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};
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/**
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* Internal state of the stream.
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* Buffered byte-oriented communication between one producer task and one consumer task. The
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* consumer owns the AppStream object and its lifetime. See app_stream_subscribe().
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* @warning `internal` is for internal use only; do not read or write its fields directly.
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*/
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struct AppStream {
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struct {
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struct AppStreamBuffer buffer;
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AppInstanceId producer_id;
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TaskHandle_t producer_task;
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/** fd this stream is installed at in producer_id's fd table; set by
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* app_stream_subscribe()/app_manager_start_with_streams(), used by
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* app_stream_unsubscribe() to find it again. */
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int producer_fd;
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struct Mutex mutex;
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/** Caller-owned group readiness is signalled on; see app_stream_subscribe(). */
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struct TaskEventGroup* event_group;
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uint32_t readable_bit;
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uint32_t writable_bit;
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bool closed;
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} internal;
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};
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/**
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* Registers @a stream as the file-like object bound to @a producer_id's fd table at
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* @a producer_fd, claiming two bits from @a event_group for its readable/writable readiness.
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* There is at most one subscriber for a given app fd. Subscribing over an existing one
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* atomically closes it first (any task blocked on it wakes; already-buffered bytes remain
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* readable until drained) and installs @a stream in its place.
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* @param[in,out] stream caller-owned. Storage must remain valid until
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* app_stream_unsubscribe()/app_stream_close() or app-exit teardown.
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* @param[in] buffer ring buffer storage; caller-owned, same validity requirement as @a stream.
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* @param[in] buffer_capacity size of @a buffer in bytes.
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* @param[in] event_group caller-owned; must outlive @a stream (i.e. be destructed only after
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* app_stream_unsubscribe()). Lets a task wait on this stream's readiness together with other
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* event sources sharing the same group via task_event_group_wait()/task_event_group_wait_any().
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* @retval ERROR_NOT_FOUND no instance with this id is running
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* @retval ERROR_OUT_OF_RANGE @a producer_fd is out of range
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* @retval ERROR_RESOURCE @a event_group has no free bits left to claim
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* @retval ERROR_NONE on success
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*/
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error_t app_stream_subscribe(struct AppStream* stream, void* buffer, size_t buffer_capacity, struct TaskEventGroup* event_group, AppInstanceId producer_id, int producer_fd);
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/** Removes @a stream from whatever fd table it was installed in, restoring the null device there,
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* and releases its two bits back to the event_group given to app_stream_subscribe(). */
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error_t app_stream_unsubscribe(struct AppStream* stream);
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/**
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* Blocks until @a stream becomes readable/writable (per @a wait) or @a timeout elapses. Checks
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* the current state directly before blocking, so a permanently-true condition (e.g. closed)
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* keeps returning immediately on every call, even though the underlying event bit itself is
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* one-shot (task_event_group_wait() clears a matched bit on exit).
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* @retval ERROR_NONE the condition is true
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* @retval ERROR_TIMEOUT @a timeout elapsed
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* @retval ERROR_ISR_STATUS called from an ISR
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*/
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error_t app_stream_await(struct AppStream* stream, AppFileWait wait, TickType_t timeout);
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/** Non-blocking: copies up to @a buffer_size currently-available bytes out of @a stream. */
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size_t app_stream_read(struct AppStream* stream, void* buffer, size_t buffer_size);
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/** Non-blocking: copies up to @a buffer_size bytes into @a stream, as much as currently fits. */
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size_t app_stream_write(struct AppStream* stream, const void* buffer, size_t buffer_size);
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/**
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* Marks @a stream closed: wakes any task blocked in app_stream_await(), and causes the other side
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* to observe EOF (reader, once drained) or a write error (writer).
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*/
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error_t app_stream_close(struct AppStream* stream);
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#ifdef __cplusplus
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}
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#endif
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