First version of the Jim eventloop extension, exporting

[after], [vwait], and the C API to write other extensions using
events. No win32 port for now, just posix. UDP extension will follow
shortly and will be the first extension using the event loop.

1 files changed, 448 insertions, 0 deletions

diff --git a/jim-eventloop.c b/jim-eventloop.c
new file mode 100644
index 0000000..0a409aa
--- /dev/null
+++ b/jim-eventloop.c
@@ -0,0 +1,448 @@
+/* Jim - Event Loop extension
+ * Copyright 2005 Salvatore Sanfilippo <antirez@invece.org>
+ *
+ * $Id: jim-eventloop.c,v 1.1 2005/04/18 08:31:26 antirez Exp $
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * A copy of the license is also included in the source distribution
+ * of Jim, as a TXT file name called LICENSE.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* TODO:
+ *
+ *  - to really use flags in Jim_ProcessEvents()
+ *  - more complete [after] command with [after info] and other subcommands.
+ *  - Win32 port
+ */
+
+#define JIM_EXTENSION
+#define __JIM_EVENTLOOP_CORE__
+#include "jim.h"
+#include "jim-eventloop.h"
+
+/* POSIX includes */
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+/* --- */
+
+/* File event structure */
+typedef struct Jim_FileEvent {
+    void *handle;
+    int mask; /* one of JIM_EVENT_(READABLE|WRITABLE|EXCEPTION) */
+    Jim_FileProc *fileProc;
+    Jim_EventFinalizerProc *finalizerProc;
+    void *clientData;
+    struct Jim_FileEvent *next;
+} Jim_FileEvent;
+
+/* Time event structure */
+typedef struct Jim_TimeEvent {
+    jim_wide id; /* time event identifier. */
+    long when_sec; /* seconds */
+    long when_ms; /* milliseconds */
+    Jim_TimeProc *timeProc;
+    Jim_EventFinalizerProc *finalizerProc;
+    void *clientData;
+    struct Jim_TimeEvent *next;
+} Jim_TimeEvent;
+
+/* Per-interp stucture containing the state of the event loop */
+typedef struct Jim_EventLoop {
+    jim_wide timeEventNextId;
+    Jim_FileEvent *fileEventHead;
+    Jim_TimeEvent *timeEventHead;
+} Jim_EventLoop;
+
+void Jim_CreateFileHandler(Jim_Interp *interp, void *handle, int mask,
+        Jim_FileProc *proc, void *clientData,
+        Jim_EventFinalizerProc *finalizerProc)
+{
+    Jim_FileEvent *fe;
+    Jim_EventLoop *eventLoop = Jim_GetAssocData(interp, "eventloop");
+
+    fe = Jim_Alloc(sizeof(*fe));
+    fe->handle = handle;
+    fe->mask = mask;
+    fe->fileProc = proc;
+    fe->finalizerProc = finalizerProc;
+    fe->clientData = clientData;
+    fe->next = eventLoop->fileEventHead;
+    eventLoop->fileEventHead = fe;
+}
+
+void Jim_DeleteFileHandler(Jim_Interp *interp, void *handle)
+{
+    Jim_FileEvent *fe, *prev = NULL;
+    Jim_EventLoop *eventLoop = Jim_GetAssocData(interp, "eventloop");
+
+    fe = eventLoop->fileEventHead;
+    while(fe) {
+        if (fe->handle == handle) {
+            if (prev == NULL)
+                eventLoop->fileEventHead = fe->next;
+            else
+                prev->next = fe->next;
+            if (fe->finalizerProc)
+                fe->finalizerProc(interp, fe->clientData);
+            Jim_Free(fe);
+            return;
+        }
+        prev = fe;
+        fe = fe->next;
+    }
+}
+
+/* That's another part of this extension that needs to be ported
+ * to WIN32. */
+static void JimGetTime(long *seconds, long *milliseconds)
+{
+    struct timeval tv;
+
+    gettimeofday(&tv, NULL);
+    *seconds = tv.tv_sec;
+    *milliseconds = tv.tv_usec/1000;
+}
+
+jim_wide Jim_CreateTimeHandler(Jim_Interp *interp, jim_wide milliseconds,
+        Jim_TimeProc *proc, void *clientData,
+        Jim_EventFinalizerProc *finalizerProc)
+{
+    Jim_EventLoop *eventLoop = Jim_GetAssocData(interp, "eventloop");
+    jim_wide id = eventLoop->timeEventNextId++;
+    Jim_TimeEvent *te;
+    long cur_sec, cur_ms;
+
+    JimGetTime(&cur_sec, &cur_ms);
+
+    te = Jim_Alloc(sizeof(*te));
+    te->id = id;
+    te->when_sec = cur_sec + milliseconds/1000;
+    te->when_ms = cur_ms + milliseconds%1000;
+    if (te->when_ms >= 1000) {
+        te->when_sec ++;
+        te->when_ms -= 1000;
+    }
+    te->timeProc = proc;
+    te->finalizerProc = finalizerProc;
+    te->clientData = clientData;
+    te->next = eventLoop->timeEventHead;
+    eventLoop->timeEventHead = te;
+    return id;
+}
+
+int Jim_DeleteTimeHandler(Jim_Interp *interp, jim_wide id)
+{
+    Jim_TimeEvent *te, *prev = NULL;
+    Jim_EventLoop *eventLoop = Jim_GetAssocData(interp, "eventloop");
+
+    te = eventLoop->timeEventHead;
+    while(te) {
+        if (te->id == id) {
+            if (prev == NULL)
+                eventLoop->timeEventHead = te->next;
+            else
+                prev->next = te->next;
+            if (te->finalizerProc)
+                te->finalizerProc(interp, te->clientData);
+            Jim_Free(te);
+            return JIM_OK;
+        }
+        prev = te;
+        te = te->next;
+    }
+    return JIM_ERR; /* NO event with the specified ID found */
+}
+
+/* Search the first timer to fire.
+ * This operation is useful to know how many time the select can be
+ * put in sleep without to delay any event.
+ * If there are no timers NULL is returned. */
+static Jim_TimeEvent *JimSearchNearestTimer(Jim_EventLoop *eventLoop)
+{
+    Jim_TimeEvent *te = eventLoop->timeEventHead;
+    Jim_TimeEvent *nearest = NULL;
+
+    while(te) {
+        if (!nearest || te->when_sec < nearest->when_sec ||
+                (te->when_sec == nearest->when_sec &&
+                 te->when_ms < nearest->when_ms))
+            nearest = te;
+        te = te->next;
+    }
+    return nearest;
+}
+
+/* --- POSIX version of Jim_ProcessEvents, for now the only available --- */
+#define JIM_FILE_EVENTS 1
+#define JIM_TIME_EVENTS 2
+#define JIM_ALL_EVENTS (JIM_FILE_EVENTS|JIM_TIME_EVENTS)
+#define JIM_DONT_WAIT 4
+
+/* Process every pending time event, then every pending file event
+ * (that may be registered by time event callbacks just processed).
+ * Without special flags the function sleeps until some file event
+ * fires, or when the next time event occurrs (if any).
+ *
+ * If flags is 0, the function does nothing and returns.
+ * if flags has JIM_ALL_EVENTS set, all the kind of events are processed.
+ * if flags has JIM_FILE_EVENTS set, file events are processed.
+ * if flags has JIM_TIME_EVENTS set, time events are processed.
+ * if flags has JIM_DONT_WAIT set the function returns ASAP until all
+ * the events that's possible to process without to wait are processed.
+ *
+ * The function returns the number of events processed. */
+int Jim_ProcessEvents(Jim_Interp *interp, int flags)
+{
+    int maxfd = 0, numfd = 0, processed = 0;
+    fd_set rfds, wfds, efds;
+    Jim_EventLoop *eventLoop = Jim_GetAssocData(interp, "eventloop");
+    Jim_FileEvent *fe = eventLoop->fileEventHead;
+    Jim_TimeEvent *te;
+    jim_wide maxId;
+    JIM_NOTUSED(flags);
+
+    FD_ZERO(&rfds);
+    FD_ZERO(&wfds);
+    FD_ZERO(&efds);
+
+    /* Check file events */
+    while (fe != NULL) {
+        int fd = (int) fe->handle;
+
+        if (fe->mask & JIM_EVENT_READABLE) FD_SET(fd, &rfds);
+        if (fe->mask & JIM_EVENT_WRITABLE) FD_SET(fd, &rfds);
+        if (fe->mask & JIM_EVENT_EXCEPTION) FD_SET(fd, &rfds);
+        if (maxfd < fd) maxfd = fd;
+        numfd++;
+        fe = fe->next;
+    }
+    /* Note that we want call select() even if there are no
+     * file events to process as long as we want to process time
+     * events, in order to sleep until the next time event is ready
+     * to fire. */
+    if (numfd || ((flags & JIM_TIME_EVENTS) && !(flags & JIM_DONT_WAIT))) {
+        int retval;
+        Jim_TimeEvent *shortest;
+        struct timeval tv, *tvp;
+
+        shortest = JimSearchNearestTimer(eventLoop);
+        if (shortest) {
+            long now_sec, now_ms;
+
+            /* Calculate the time missing for the nearest
+             * timer to fire. */
+            JimGetTime(&now_sec, &now_ms);
+            tvp = &tv;
+            tvp->tv_sec = shortest->when_sec - now_sec;
+            if (shortest->when_ms < now_ms) {
+                tvp->tv_usec = ((shortest->when_ms+1000) - now_ms)*1000;
+                tvp->tv_sec --;
+            } else {
+                tvp->tv_usec = (shortest->when_ms - now_ms)*1000;
+            }
+        } else {
+            tvp = NULL; /* wait forever */
+        }
+
+        retval = select(maxfd+1, &rfds, &wfds, &efds, tvp);
+        if (retval) {
+            fe = eventLoop->fileEventHead;
+            while(fe != NULL) {
+                int fd = (int) fe->handle;
+
+                if ((fe->mask & JIM_EVENT_READABLE && FD_ISSET(fd, &rfds)) ||
+                    (fe->mask & JIM_EVENT_WRITABLE && FD_ISSET(fd, &wfds)) ||
+                    (fe->mask & JIM_EVENT_EXCEPTION && FD_ISSET(fd, &efds)))
+                {
+                    int mask = 0;
+
+                    if (fe->mask & JIM_EVENT_READABLE && FD_ISSET(fd, &rfds))
+                        mask |= JIM_EVENT_READABLE;
+                    if (fe->mask & JIM_EVENT_WRITABLE && FD_ISSET(fd, &wfds))
+                        mask |= JIM_EVENT_WRITABLE;
+                    if (fe->mask & JIM_EVENT_EXCEPTION && FD_ISSET(fd, &efds))
+                        mask |= JIM_EVENT_EXCEPTION;
+                    if (fe->fileProc(interp, fe->clientData, mask) == JIM_ERR) {
+                        /* Remove the element on handler error */
+                        Jim_DeleteFileHandler(interp, fe->handle);
+                    }
+                    processed++;
+                    /* After an event is processed our file event list
+                     * may no longer be the same, so what we do
+                     * is to clear the bit for this file descriptor and
+                     * restart again from the head. */
+                    fe = eventLoop->fileEventHead;
+                    FD_CLR(fd, &rfds);
+                    FD_CLR(fd, &wfds);
+                    FD_CLR(fd, &efds);
+                } else {
+                    fe = fe->next;
+                }
+            }
+        }
+    }
+    /* Check time events */
+    te = eventLoop->timeEventHead;
+    maxId = eventLoop->timeEventNextId-1;
+    while(te) {
+        long now_sec, now_ms;
+        jim_wide id;
+
+        if (te->id > maxId) {
+            te = te->next;
+            continue;
+        }
+        JimGetTime(&now_sec, &now_ms);
+        if (now_sec > te->when_sec ||
+            (now_sec == te->when_sec && now_ms >= te->when_ms))
+        {
+            id = te->id;
+            te->timeProc(interp, te->clientData);
+            /* After an event is processed our time event list may
+             * no longer be the same, so we restart from head.
+             * Still we make sure to don't process events registered
+             * by event handlers itself in order to don't loop forever
+             * even in case an [after 0] that continuously register
+             * itself. To do so we saved the max ID we want to handle. */
+            Jim_DeleteTimeHandler(interp, id);
+            te = eventLoop->timeEventHead;
+        } else {
+            te = te->next;
+        }
+    }
+
+    return processed;
+}
+/* ---------------------------------------------------------------------- */
+
+void JimELAssocDataDeleProc(Jim_Interp *interp, void *data)
+{
+    void *next;
+    Jim_FileEvent *fe;
+    Jim_TimeEvent *te;
+    Jim_EventLoop *eventLoop = data;
+
+    fe = eventLoop->fileEventHead;
+    while(fe) {
+        next = fe->next;
+        if (fe->finalizerProc)
+            fe->finalizerProc(interp, fe->clientData);
+        Jim_Free(fe);
+        fe = next;
+    }
+
+    te = eventLoop->timeEventHead;
+    while(te) {
+        next = te->next;
+        if (te->finalizerProc)
+            te->finalizerProc(interp, te->clientData);
+        Jim_Free(te);
+        te = next;
+    }
+    Jim_Free(data);
+}
+
+static int JimELVwaitCommand(Jim_Interp *interp, int argc, 
+        Jim_Obj *const *argv)
+{
+    Jim_Obj *oldValue;
+
+    if (argc != 2) {
+        Jim_WrongNumArgs(interp, 1, argv, "name");
+        return JIM_ERR;
+    }
+    oldValue = Jim_GetGlobalVariable(interp, argv[1], JIM_NONE);
+    if (oldValue) Jim_IncrRefCount(oldValue);
+    while (1) {
+        Jim_Obj *currValue;
+
+        Jim_ProcessEvents(interp, JIM_ALL_EVENTS);
+        currValue = Jim_GetGlobalVariable(interp, argv[1], JIM_NONE);
+        /* Stop the loop if the vwait-ed variable changed value,
+         * or if was unset and now is set (or the contrary). */
+        if ((oldValue && !currValue) ||
+            (!oldValue && currValue) ||
+            (oldValue && currValue &&
+             !Jim_StringEqObj(oldValue, currValue, JIM_CASESENS)))
+            break;
+    }
+    if (oldValue) Jim_DecrRefCount(interp, oldValue);
+    return JIM_OK;
+}
+
+void JimAfterTimeHandler(Jim_Interp *interp, void *clientData)
+{
+    Jim_Obj *objPtr = clientData;
+
+    Jim_EvalObjBackground(interp, objPtr);
+}
+
+void JimAfterTimeEventFinalizer(Jim_Interp *interp, void *clientData)
+{
+    Jim_Obj *objPtr = clientData;
+
+    Jim_DecrRefCount(interp, objPtr);
+}
+
+static int JimELAfterCommand(Jim_Interp *interp, int argc, 
+        Jim_Obj *const *argv)
+{
+    jim_wide ms, id;
+    Jim_Obj *objPtr, *idObjPtr;
+
+    if (argc != 3) {
+        Jim_WrongNumArgs(interp, 1, argv, "after milliseconds script");
+        return JIM_ERR;
+    }
+    if (Jim_GetWide(interp, argv[1], &ms) != JIM_OK)
+        return JIM_ERR;
+    Jim_IncrRefCount(argv[2]);
+    id = Jim_CreateTimeHandler(interp, ms, JimAfterTimeHandler, argv[2],
+            JimAfterTimeEventFinalizer);
+    objPtr = Jim_NewStringObj(interp, NULL, 0);
+    Jim_AppendString(interp, objPtr, "after#", -1);
+    idObjPtr = Jim_NewIntObj(interp, id);
+    Jim_IncrRefCount(idObjPtr);
+    Jim_AppendObj(interp, objPtr, idObjPtr);
+    Jim_DecrRefCount(interp, idObjPtr);
+    Jim_SetResult(interp, objPtr);
+    return JIM_OK;
+}
+
+int Jim_OnLoad(Jim_Interp *interp)
+{
+    Jim_EventLoop *eventLoop;
+
+    Jim_InitExtension(interp);
+    if (Jim_PackageProvide(interp, "eventloop", "1.0", JIM_ERRMSG) != JIM_OK)
+        return JIM_ERR;
+
+    eventLoop = Jim_Alloc(sizeof(*eventLoop));
+    eventLoop->fileEventHead = NULL;
+    eventLoop->timeEventHead = NULL;
+    eventLoop->timeEventNextId = 0;
+    Jim_SetAssocData(interp, "eventloop", JimELAssocDataDeleProc, eventLoop);
+
+    Jim_CreateCommand(interp, "vwait", JimELVwaitCommand, NULL, NULL);
+    Jim_CreateCommand(interp, "after", JimELAfterCommand, NULL, NULL);
+
+    /* Export events API */
+    Jim_RegisterApi(interp, "Jim_CreateFileHandler", Jim_CreateFileHandler);
+    Jim_RegisterApi(interp, "Jim_DeleteFileHandler", Jim_DeleteFileHandler);
+    Jim_RegisterApi(interp, "Jim_CreateTimeHandler", Jim_CreateTimeHandler);
+    Jim_RegisterApi(interp, "Jim_DeleteTimeHandler", Jim_DeleteTimeHandler);
+    Jim_RegisterApi(interp, "Jim_ProcessEvents", Jim_ProcessEvents);
+    return JIM_OK;
+}