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Diffstat (limited to 'include/my_context.h')
| -rw-r--r-- | include/my_context.h | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/include/my_context.h b/include/my_context.h new file mode 100644 index 00000000..ea0e3496 --- /dev/null +++ b/include/my_context.h @@ -0,0 +1,232 @@ +/* + Copyright 2011 Kristian Nielsen and Monty Program Ab + + This file is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this. If not, see <http://www.gnu.org/licenses/>. +*/ + +/* + Simple API for spawning a co-routine, to be used for async libmysqlclient. + + Idea is that by implementing this interface using whatever facilities are + available for given platform, we can use the same code for the generic + libmysqlclient-async code. + + (This particular implementation uses Posix ucontext swapcontext().) +*/ + +#ifdef __WIN__ +#define MY_CONTEXT_USE_WIN32_FIBERS 1 +#elif defined(__GNUC__) && __GNUC__ >= 3 && defined(__x86_64__) && !defined(__ILP32__) +#define MY_CONTEXT_USE_X86_64_GCC_ASM +#elif defined(__GNUC__) && __GNUC__ >= 3 && defined(__i386__) +#define MY_CONTEXT_USE_I386_GCC_ASM +#elif defined(HAVE_UCONTEXT_H) +#define MY_CONTEXT_USE_UCONTEXT +#else +#define MY_CONTEXT_DISABLE +#endif + +#ifdef MY_CONTEXT_USE_WIN32_FIBERS +struct my_context { + void (*user_func)(void *); + void *user_arg; + void *app_fiber; + void *lib_fiber; + int return_value; +#ifndef DBUG_OFF + void *dbug_state; +#endif +}; +#endif + + +#ifdef MY_CONTEXT_USE_UCONTEXT +#include <ucontext.h> + +struct my_context { + void (*user_func)(void *); + void *user_data; + void *stack; + size_t stack_size; + ucontext_t base_context; + ucontext_t spawned_context; + int active; +#ifdef HAVE_VALGRIND_MEMCHECK_H + unsigned int valgrind_stack_id; +#endif +#ifndef DBUG_OFF + void *dbug_state; +#endif +}; +#endif + + +#ifdef MY_CONTEXT_USE_X86_64_GCC_ASM +#include <stdint.h> + +struct my_context { + uint64_t save[9]; + void *stack_top; + void *stack_bot; +#ifdef HAVE_VALGRIND_MEMCHECK_H + unsigned int valgrind_stack_id; +#endif +#ifndef DBUG_OFF + void *dbug_state; +#endif +}; +#endif + + +#ifdef MY_CONTEXT_USE_I386_GCC_ASM +#include <stdint.h> + +struct my_context { + uint64_t save[7]; + void *stack_top; + void *stack_bot; +#ifdef HAVE_VALGRIND_MEMCHECK_H + unsigned int valgrind_stack_id; +#endif +#ifndef DBUG_OFF + void *dbug_state; +#endif +}; +#endif + + +#ifdef MY_CONTEXT_DISABLE +struct my_context { + int dummy; +}; +#endif + + +/* + Initialize an asynchroneous context object. + Returns 0 on success, non-zero on failure. +*/ +extern int my_context_init(struct my_context *c, size_t stack_size); + +/* Free an asynchroneous context object, deallocating any resources used. */ +extern void my_context_destroy(struct my_context *c); + +/* + Spawn an asynchroneous context. The context will run the supplied user + function, passing the supplied user data pointer. + + The context must have been initialised with my_context_init() prior to + this call. + + The user function may call my_context_yield(), which will cause this + function to return 1. Then later my_context_continue() may be called, which + will resume the asynchroneous context by returning from the previous + my_context_yield() call. + + When the user function returns, this function returns 0. + + In case of error, -1 is returned. +*/ +extern int my_context_spawn(struct my_context *c, void (*f)(void *), void *d); + +/* + Suspend an asynchroneous context started with my_context_spawn. + + When my_context_yield() is called, execution immediately returns from the + last my_context_spawn() or my_context_continue() call. Then when later + my_context_continue() is called, execution resumes by returning from this + my_context_yield() call. + + Returns 0 if ok, -1 in case of error. +*/ +extern int my_context_yield(struct my_context *c); + +/* + Resume an asynchroneous context. The context was spawned by + my_context_spawn(), and later suspended inside my_context_yield(). + + The asynchroneous context may be repeatedly suspended with + my_context_yield() and resumed with my_context_continue(). + + Each time it is suspended, this function returns 1. When the originally + spawned user function returns, this function returns 0. + + In case of error, -1 is returned. +*/ +extern int my_context_continue(struct my_context *c); + + +struct mysql_async_context { + /* + This is set to the value that should be returned from foo_start() or + foo_cont() when a call is suspended. + */ + unsigned int events_to_wait_for; + /* + It is also set to the event(s) that triggered when a suspended call is + resumed, eg. whether we woke up due to connection completed or timeout + in mysql_real_connect_cont(). + */ + unsigned int events_occurred; + /* + This is set to the result of the whole asynchronous operation when it + completes. It uses a union, as different calls have different return + types. + */ + union { + void *r_ptr; + const void *r_const_ptr; + int r_int; + my_bool r_my_bool; + } ret_result; + /* + The timeout value (in millisecods), for suspended calls that need to wake + up on a timeout (eg. mysql_real_connect_start(). + */ + unsigned int timeout_value; + /* + This flag is set when we are executing inside some asynchronous call + foo_start() or foo_cont(). It is used to decide whether to use the + synchronous or asynchronous version of calls that may block such as + recv(). + + Note that this flag is not set when a call is suspended, eg. after + returning from foo_start() and before re-entering foo_cont(). + */ + my_bool active; + /* + This flag is set when an asynchronous operation is in progress, but + suspended. Ie. it is set when foo_start() or foo_cont() returns because + the operation needs to block, suspending the operation. + + It is used to give an error (rather than crash) if the application + attempts to call some foo_cont() method when no suspended operation foo is + in progress. + */ + my_bool suspended; + /* + If non-NULL, this is a pointer to a callback hook that will be invoked with + the user data argument just before the context is suspended, and just after + it is resumed. + */ + void (*suspend_resume_hook)(my_bool suspend, void *user_data); + void *suspend_resume_hook_user_data; + /* + This is used to save the execution contexts so that we can suspend an + operation and switch back to the application context, to resume the + suspended context later when the application re-invokes us with + foo_cont(). + */ + struct my_context async_context; +}; |