zend_fibers.h

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/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) Zend Technologies Ltd. (http://www.zend.com)           |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.00 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.zend.com/license/2_00.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Aaron Piotrowski <aaron@trowski.com>                        |
   |          Martin Schröder <m.schroeder2007@gmail.com>                 |
   +----------------------------------------------------------------------+
*/
 
#ifndef ZEND_FIBERS_H
#define ZEND_FIBERS_H
 
#include "zend_API.h"
#include "zend_types.h"
 
#define ZEND_FIBER_GUARD_PAGES 1
 
#define ZEND_FIBER_DEFAULT_C_STACK_SIZE (4096 * (((sizeof(void *)) < 8) ? 256 : 512))
#define ZEND_FIBER_VM_STACK_SIZE (1024 * sizeof(zval))
 
BEGIN_EXTERN_C()
 
typedef enum {
    ZEND_FIBER_STATUS_INIT,
    ZEND_FIBER_STATUS_RUNNING,
    ZEND_FIBER_STATUS_SUSPENDED,
    ZEND_FIBER_STATUS_DEAD,
} zend_fiber_status;
 
typedef enum {
    ZEND_FIBER_FLAG_THREW     = 1 << 0,
    ZEND_FIBER_FLAG_BAILOUT   = 1 << 1,
    ZEND_FIBER_FLAG_DESTROYED = 1 << 2,
} zend_fiber_flag;
 
typedef enum {
    ZEND_FIBER_TRANSFER_FLAG_ERROR = 1 << 0,
    ZEND_FIBER_TRANSFER_FLAG_BAILOUT = 1 << 1
} zend_fiber_transfer_flag;
 
void zend_register_fiber_ce(void);
void zend_fiber_init(void);
void zend_fiber_shutdown(void);
 
extern ZEND_API zend_class_entry *zend_ce_fiber;
 
typedef struct _zend_fiber_stack zend_fiber_stack;
 
/* Encapsulates data needed for a context switch. */
typedef struct _zend_fiber_transfer {
    /* Fiber that will be switched to / has resumed us. */
    zend_fiber_context *context;
 
    /* Value to that should be send to (or was received from) a fiber. */
    zval value;
 
    /* Bitmask of flags defined in enum zend_fiber_transfer_flag. */
    uint8_t flags;
} zend_fiber_transfer;
 
/* Coroutine functions must populate the given transfer with a new context
 * and (optional) data before they return. */
typedef void (*zend_fiber_coroutine)(zend_fiber_transfer *transfer);
typedef void (*zend_fiber_clean)(zend_fiber_context *context);
 
struct _zend_fiber_context {
    /* Pointer to boost.context or ucontext_t data. */
    void *handle;
 
    /* Pointer that identifies the fiber type. */
    void *kind;
 
    /* Entrypoint function of the fiber. */
    zend_fiber_coroutine function;
 
    /* Cleanup function for fiber. */
    zend_fiber_clean cleanup;
 
    /* Assigned C stack. */
    zend_fiber_stack *stack;
 
    /* Fiber status. */
    zend_fiber_status status;
 
    /* Observer state */
    zend_execute_data *top_observed_frame;
 
    /* Reserved for extensions */
    void *reserved[ZEND_MAX_RESERVED_RESOURCES];
};
 
struct _zend_fiber {
    /* PHP object handle. */
    zend_object std;
 
    /* Flags are defined in enum zend_fiber_flag. */
    uint8_t flags;
 
    /* Native C fiber context. */
    zend_fiber_context context;
 
    /* Fiber that resumed us. */
    zend_fiber_context *caller;
 
    /* Fiber that suspended us. */
    zend_fiber_context *previous;
 
    /* Callback and info / cache to be used when fiber is started. */
    zend_fcall_info fci;
    zend_fcall_info_cache fci_cache;
 
    /* Current Zend VM execute data being run by the fiber. */
    zend_execute_data *execute_data;
 
    /* Frame on the bottom of the fiber vm stack. */
    zend_execute_data *stack_bottom;
 
    /* Active fiber vm stack. */
    zend_vm_stack vm_stack;
 
    /* Storage for fiber return value. */
    zval result;
};
 
ZEND_API zend_result zend_fiber_start(zend_fiber *fiber, zval *return_value);
ZEND_API void zend_fiber_resume(zend_fiber *fiber, zval *value, zval *return_value);
ZEND_API void zend_fiber_suspend(zend_fiber *fiber, zval *value, zval *return_value);
 
/* These functions may be used to create custom fiber objects using the bundled fiber switching context. */
ZEND_API zend_result zend_fiber_init_context(zend_fiber_context *context, void *kind, zend_fiber_coroutine coroutine, size_t stack_size);
ZEND_API void zend_fiber_destroy_context(zend_fiber_context *context);
ZEND_API void zend_fiber_switch_context(zend_fiber_transfer *transfer);
#ifdef ZEND_CHECK_STACK_LIMIT
ZEND_API void* zend_fiber_stack_limit(zend_fiber_stack *stack);
ZEND_API void* zend_fiber_stack_base(zend_fiber_stack *stack);
#endif /* ZEND_CHECK_STACK_LIMIT */
 
ZEND_API void zend_fiber_switch_block(void);
ZEND_API void zend_fiber_switch_unblock(void);
ZEND_API bool zend_fiber_switch_blocked(void);
 
END_EXTERN_C()
 
static zend_always_inline zend_fiber *zend_fiber_from_context(zend_fiber_context *context)
{
    ZEND_ASSERT(context->kind == zend_ce_fiber && "Fiber context does not belong to a Zend fiber");
 
    return (zend_fiber *)(((char *) context) - XtOffsetOf(zend_fiber, context));
}
 
static zend_always_inline zend_fiber_context *zend_fiber_get_context(zend_fiber *fiber)
{
    return &fiber->context;
}
 
#endif