150 lines
5.1 KiB
C
150 lines
5.1 KiB
C
/* channel.h -- the channel type for Go.
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Copyright 2009 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include <stdint.h>
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#include <pthread.h>
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#include "go-type.h"
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/* This structure is used when a select is waiting for a synchronous
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channel. */
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struct __go_channel_select
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{
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/* A pointer to the next select waiting for this channel. */
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struct __go_channel_select *next;
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/* A pointer to the channel which this select will use. This starts
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out as NULL and is set to the first channel which synchs up with
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this one. This variable to which this points may only be
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accessed when __go_select_data_mutex is held. */
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struct __go_channel **selected;
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/* A pointer to a variable which must be set to true if the
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goroutine which sets *SELECTED wants to read from the channel,
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false if it wants to write to it. */
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_Bool *is_read;
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};
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/* A channel is a pointer to this structure. */
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struct __go_channel
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{
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/* A mutex to control access to the channel. */
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pthread_mutex_t lock;
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/* A condition variable. This is signalled when data is added to
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the channel and when data is removed from the channel. */
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pthread_cond_t cond;
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/* The type of elements on this channel. */
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const struct __go_type_descriptor *element_type;
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/* True if a goroutine is waiting to send on a synchronous
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channel. */
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_Bool waiting_to_send;
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/* True if a goroutine is waiting to receive on a synchronous
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channel. */
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_Bool waiting_to_receive;
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/* True if this channel was selected for send in a select statement.
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This looks out all other sends. */
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_Bool selected_for_send;
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/* True if this channel was selected for receive in a select
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statement. This locks out all other receives. */
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_Bool selected_for_receive;
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/* True if this channel has been closed. */
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_Bool is_closed;
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/* The list of select statements waiting to send on a synchronous
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channel. */
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struct __go_channel_select *select_send_queue;
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/* The list of select statements waiting to receive on a synchronous
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channel. */
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struct __go_channel_select *select_receive_queue;
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/* If a select statement is waiting for this channel, it sets these
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pointers. When something happens on the channel, the channel
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locks the mutex, signals the condition, and unlocks the
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mutex. */
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pthread_mutex_t *select_mutex;
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pthread_cond_t *select_cond;
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/* The number of entries in the circular buffer. */
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unsigned int num_entries;
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/* Where to store the next value. */
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unsigned int next_store;
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/* Where to fetch the next value. If next_fetch == next_store, the
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buffer is empty. If next_store + 1 == next_fetch, the buffer is
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full. */
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unsigned int next_fetch;
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/* The circular buffer. */
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uint64_t data[];
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};
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/* Try to link up with the structure generated by the frontend. */
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typedef struct __go_channel __go_channel;
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/* The mutex used to control access to the value pointed to by the
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__go_channel_select selected field. No additional mutexes may be
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acquired while this mutex is held. */
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extern pthread_mutex_t __go_select_data_mutex;
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extern struct __go_channel *
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__go_new_channel (const struct __go_type_descriptor *, uintptr_t);
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extern _Bool __go_synch_with_select (struct __go_channel *, _Bool);
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extern void __go_broadcast_to_select (struct __go_channel *);
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extern void __go_send_acquire (struct __go_channel *, _Bool);
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extern _Bool __go_send_nonblocking_acquire (struct __go_channel *);
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extern void __go_send_release (struct __go_channel *);
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extern void __go_send_small (struct __go_channel *, uint64_t, _Bool);
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extern _Bool __go_send_nonblocking_small (struct __go_channel *, uint64_t);
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extern void __go_send_big (struct __go_channel *, const void *, _Bool);
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extern _Bool __go_send_nonblocking_big (struct __go_channel *, const void *);
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extern _Bool __go_receive_acquire (struct __go_channel *, _Bool);
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#define RECEIVE_NONBLOCKING_ACQUIRE_DATA 0
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#define RECEIVE_NONBLOCKING_ACQUIRE_NODATA 1
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#define RECEIVE_NONBLOCKING_ACQUIRE_CLOSED 2
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extern int __go_receive_nonblocking_acquire (struct __go_channel *);
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extern uint64_t __go_receive_small (struct __go_channel *, _Bool);
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extern uint64_t __go_receive_small_closed (struct __go_channel *, _Bool,
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_Bool *);
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extern void __go_receive_release (struct __go_channel *);
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struct __go_receive_nonblocking_small
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{
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/* Value read from channel, or 0. */
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uint64_t __val;
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/* True if value was read from channel. */
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_Bool __success;
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/* True if channel is closed. */
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_Bool __closed;
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};
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extern struct __go_receive_nonblocking_small
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__go_receive_nonblocking_small (struct __go_channel *);
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extern _Bool __go_receive_big (struct __go_channel *, void *, _Bool);
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extern _Bool __go_receive_nonblocking_big (struct __go_channel *, void *,
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_Bool *);
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extern void __go_unlock_and_notify_selects (struct __go_channel *);
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extern _Bool __go_builtin_closed (struct __go_channel *);
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extern void __go_builtin_close (struct __go_channel *);
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extern int __go_chan_len (struct __go_channel *);
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extern int __go_chan_cap (struct __go_channel *);
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