diff options
Diffstat (limited to 'adapters')
| -rw-r--r-- | adapters/poll.h | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/adapters/poll.h b/adapters/poll.h new file mode 100644 index 0000000..f138650 --- /dev/null +++ b/adapters/poll.h @@ -0,0 +1,197 @@ + +#ifndef HIREDIS_POLL_H +#define HIREDIS_POLL_H + +#include "../async.h" +#include "../sockcompat.h" +#include <string.h> // for memset +#include <errno.h> + +/* Values to return from redisPollTick */ +#define REDIS_POLL_HANDLED_READ 1 +#define REDIS_POLL_HANDLED_WRITE 2 +#define REDIS_POLL_HANDLED_TIMEOUT 4 + +/* An adapter to allow manual polling of the async context by checking the state + * of the underlying file descriptor. Useful in cases where there is no formal + * IO event loop but regular ticking can be used, such as in game engines. */ + +typedef struct redisPollEvents { + redisAsyncContext *context; + redisFD fd; + char reading, writing; + char in_tick; + char deleted; + double deadline; +} redisPollEvents; + +static double redisPollTimevalToDouble(struct timeval *tv) { + if (tv == NULL) + return 0.0; + return tv->tv_sec + tv->tv_usec / 1000000.00; +} + +static double redisPollGetNow(void) { +#ifndef _MSC_VER + struct timeval tv; + gettimeofday(&tv,NULL); + return redisPollTimevalToDouble(&tv); +#else + FILETIME ft; + ULARGE_INTEGER li; + GetSystemTimeAsFileTime(&ft); + li.HighPart = ft.dwHighDateTime; + li.LowPart = ft.dwLowDateTime; + return (double)li.QuadPart * 1e-7; +#endif +} + +/* Poll for io, handling any pending callbacks. The timeout argument can be + * positive to wait for a maximum given time for IO, zero to poll, or negative + * to wait forever */ +static int redisPollTick(redisAsyncContext *ac, double timeout) { + int reading, writing; + struct pollfd pfd; + int handled; + int ns; + int itimeout; + + redisPollEvents *e = (redisPollEvents*)ac->ev.data; + if (!e) + return 0; + + /* local flags, won't get changed during callbacks */ + reading = e->reading; + writing = e->writing; + if (!reading && !writing) + return 0; + + pfd.fd = e->fd; + pfd.events = 0; + if (reading) + pfd.events = POLLIN; + if (writing) + pfd.events |= POLLOUT; + + if (timeout >= 0.0) { + itimeout = (int)(timeout * 1000.0); + } else { + itimeout = -1; + } + + ns = poll(&pfd, 1, itimeout); + if (ns < 0) { + /* ignore the EINTR error */ + if (errno != EINTR) + return ns; + ns = 0; + } + + handled = 0; + e->in_tick = 1; + if (ns) { + if (reading && (pfd.revents & POLLIN)) { + redisAsyncHandleRead(ac); + handled |= REDIS_POLL_HANDLED_READ; + } + /* on Windows, connection failure is indicated with the Exception fdset. + * handle it the same as writable. */ + if (writing && (pfd.revents & (POLLOUT | POLLERR))) { + /* context Read callback may have caused context to be deleted, e.g. + by doing an redisAsyncDisconnect() */ + if (!e->deleted) { + redisAsyncHandleWrite(ac); + handled |= REDIS_POLL_HANDLED_WRITE; + } + } + } + + /* perform timeouts */ + if (!e->deleted && e->deadline != 0.0) { + double now = redisPollGetNow(); + if (now >= e->deadline) { + /* deadline has passed. disable timeout and perform callback */ + e->deadline = 0.0; + redisAsyncHandleTimeout(ac); + handled |= REDIS_POLL_HANDLED_TIMEOUT; + } + } + + /* do a delayed cleanup if required */ + if (e->deleted) + hi_free(e); + else + e->in_tick = 0; + + return handled; +} + +static void redisPollAddRead(void *data) { + redisPollEvents *e = (redisPollEvents*)data; + e->reading = 1; +} + +static void redisPollDelRead(void *data) { + redisPollEvents *e = (redisPollEvents*)data; + e->reading = 0; +} + +static void redisPollAddWrite(void *data) { + redisPollEvents *e = (redisPollEvents*)data; + e->writing = 1; +} + +static void redisPollDelWrite(void *data) { + redisPollEvents *e = (redisPollEvents*)data; + e->writing = 0; +} + +static void redisPollCleanup(void *data) { + redisPollEvents *e = (redisPollEvents*)data; + + /* if we are currently processing a tick, postpone deletion */ + if (e->in_tick) + e->deleted = 1; + else + hi_free(e); +} + +static void redisPollScheduleTimer(void *data, struct timeval tv) +{ + redisPollEvents *e = (redisPollEvents*)data; + double now = redisPollGetNow(); + e->deadline = now + redisPollTimevalToDouble(&tv); +} + +static int redisPollAttach(redisAsyncContext *ac) { + redisContext *c = &(ac->c); + redisPollEvents *e; + + /* Nothing should be attached when something is already attached */ + if (ac->ev.data != NULL) + return REDIS_ERR; + + /* Create container for context and r/w events */ + e = (redisPollEvents*)hi_malloc(sizeof(*e)); + if (e == NULL) + return REDIS_ERR; + memset(e, 0, sizeof(*e)); + + e->context = ac; + e->fd = c->fd; + e->reading = e->writing = 0; + e->in_tick = e->deleted = 0; + e->deadline = 0.0; + + /* Register functions to start/stop listening for events */ + ac->ev.addRead = redisPollAddRead; + ac->ev.delRead = redisPollDelRead; + ac->ev.addWrite = redisPollAddWrite; + ac->ev.delWrite = redisPollDelWrite; + ac->ev.scheduleTimer = redisPollScheduleTimer; + ac->ev.cleanup = redisPollCleanup; + ac->ev.data = e; + + return REDIS_OK; +} +#endif /* HIREDIS_POLL_H */ |