Import from compactor

libuevent.c

@@ -0,0 +1,439 @@
+/**
+ * @file
+ * Micro event library libuevent.
+ * Asynchronous event / mainloop library.
+ * Not thread safe!
+ * The ctxt structure needs mutex protection in case of multithreaded access
+ * $Id:$
+ *
+ * (C) Copyright 2012 flemming.madsen at madsensoft.dk. See libuevent.h
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <sys/times.h>
+#include <fcntl.h>
+#include <time.h>
+#include <poll.h>
+#include <errno.h>
+#include <assert.h>
+#include "llist.h"
+#include "libuevent.h"
+
+#ifdef DEBUG
+#define Debug(f, args...) printf(f "\n", ##args)
+#else
+#define Debug(f, args...) 
+#endif
+
+static clock_t clock_tick = 0;
+
+/// Enumerate file handle direction
+enum LUEFhDirectionT {LUE_FHIN = 0, LUE_FHOUT = 1};
+
+/// File event handle
+struct LUEFileEventH
+{
+   LListField(struct LUEFileEventH); ///< Elements for linked list
+
+   int            fd;              ///< File descriptor
+   enum LUEFhDirectionT direction; ///< Direction: in or out
+   int            pollIx;          ///< This file handle index into list of file handles to poll
+   LUEFileHandler handler;         ///< File handler callback
+   void          *data;            ///< File handler callback parameter
+};
+
+/// Timer context object
+struct LUETimerH
+{
+   LListField(struct LUETimerH);   ///< Linked list elements
+
+   int            dueTime;  ///< Epoch timestamp
+   LUETimerHandler handler; ///< Timer callback
+   void          *data;     ///< Timer callback parameter
+};
+
+/**
+ * @cond doxygen does not like this construction
+ */
+typedef LList(struct LUETimerH) LUETimerHandlerDL;
+typedef LList(struct LUEFileEventH) LUEFileEventDL;
+/**
+ * @endcond
+ */
+
+/// Main lue context object
+struct LUECtxt
+{
+   LUEFileEventDL fileHandlers;       ///< File handlers
+   LUETimerHandlerDL timeoutHandlers; ///< Timer handlers
+
+   LUEFileEventDL fileRem;            ///< List of file handles to be garbage collected
+   LUETimerHandlerDL timeRem;         ///< List of timer handles to be garbage collected
+
+   clock_t        baseTime;           ///< Time at last timer tick
+   clock_t        setTime;            ///< Next timer tick epoch
+   int            timeSet;            ///< True if next timer epoch is set
+   int            exiting;            ///< True if the application is terminating
+};
+
+static
+struct LUEFileEventH *lueAddIO(struct LUECtxt * ctxt,
+                                  int fd, LUEFileHandler handler, void *data,
+                                  enum LUEFhDirectionT direction)
+{
+   struct LUEFileEventH *ent;
+
+   ent = (struct LUEFileEventH *) malloc(sizeof(*ent));
+   assert(ent);
+   ent->fd = fd;
+   ent->direction = direction;
+   ent->handler = handler;
+   ent->data = data;
+   ent->pollIx = -1;
+   lListAppend(&ctxt->fileHandlers, ent);
+
+   return ent;
+}
+
+/**
+ * Add an input file handler
+ */
+struct LUEFileEventH *lueAddInput(struct LUECtxt *ctxt,
+                                  int fd, LUEFileHandler handler, void *data)
+{
+    return lueAddIO(ctxt, fd, handler, data, LUE_FHIN);
+}
+
+/**
+ * Add an output file handler
+ */
+struct LUEFileEventH *lueAddOutput(struct LUECtxt *ctxt,
+                                  int fd, LUEFileHandler handler, void *data)
+{
+    return lueAddIO(ctxt, fd, handler, data, LUE_FHOUT);
+}
+
+static
+int lueRemIO(struct LUECtxt *ctxt, struct LUEFileEventH *hdl)
+{
+   struct LUEFileEventH *ent;
+
+   lListForeachIn (ent, &ctxt->fileRem)
+      if (ent == hdl)
+         return -1; // Already removed
+
+   hdl->handler = NULL;
+   lListAppend(&ctxt->fileRem, hdl);
+   return 0;
+}
+
+/**
+ * Remove all handlers for an fd
+ */
+int lueRemFd(struct LUECtxt *ctxt, int fd)
+{
+   struct LUEFileEventH *ent, *rem;
+
+   lListForeachIn(ent, &ctxt->fileHandlers)
+   {
+      if (ent->fd != fd)
+         continue;
+      lListForeachIn(rem, &ctxt->fileRem) if (rem == ent) break; // Already removed
+      if (rem) {
+         ent->handler = NULL;
+         lListAppend(&ctxt->fileRem, ent);
+      }
+   }
+   return 0;
+}
+
+/**
+ * Remove an input file handler
+ */
+int lueRemInput(struct LUECtxt *ctxt, struct LUEFileEventH *hdl)
+{
+   return lueRemIO(ctxt, hdl);
+}
+
+/**
+ * Remove an output file handler
+ */
+int lueRemOutput(struct LUECtxt *ctxt, struct LUEFileEventH *hdl)
+{
+   return lueRemIO(ctxt, hdl);
+}
+
+
+/**
+ * Remove a timer event
+ */
+int lueRemTimer(struct LUECtxt *ctxt, struct LUETimerH *hdl)
+{
+   if (hdl)
+   {
+      struct LUETimerH *ent;
+
+      lListForeachIn (ent, &ctxt->timeRem)
+         if (ent == hdl)
+            return -1; // Already removed
+
+      lListRemove(&ctxt->timeoutHandlers, hdl);
+      lListAppend(&ctxt->timeRem, hdl); // Remember to free him (at a safe time)
+   }
+   return 0;
+}
+
+/**
+ * Add a timer event
+ */
+struct LUETimerH *lueAddTimer(struct LUECtxt * ctxt, int periodMs,
+                                  LUETimerHandler handler, void *data)
+{
+   int            timeDiff;
+   clock_t        curTime;
+   struct LUETimerH *nent,
+                 *ret,
+                 *ent;
+
+   nent = (struct LUETimerH *) malloc(sizeof(*ent));
+   assert(nent);
+   nent->dueTime = periodMs;
+   nent->handler = handler;
+   nent->data = data;
+
+   if (0 == periodMs)
+   {
+      // Zero delay is a special case: A oneshot workproc: Must go first
+      lListInsertFirst(&ctxt->timeoutHandlers, nent);
+      return nent;
+
+   }
+
+   // Adjust timers.
+   // Jiffie wraparound is OK since we only care about diff time
+   curTime = ctxt->timeSet ? ctxt->setTime : times(NULL);
+   timeDiff = (curTime - ctxt->baseTime) / clock_tick * 1000
+             + ((curTime - ctxt->baseTime) % clock_tick) * 1000 / clock_tick;
+
+   ret = nent;
+   lListForeachIn(ent, &ctxt->timeoutHandlers)
+   {
+      if (ent->dueTime > timeDiff)
+         ent->dueTime -= timeDiff;
+      else
+         ent->dueTime = 0;
+      if (nent && ent->dueTime > periodMs)
+      {
+         Debug("Insert %d before %d", periodMs, ent->dueTime);
+         lListInsert(&ctxt->timeoutHandlers, nent, ent);
+         nent = NULL;
+      }
+   }
+   if (nent) 
+   {
+      Debug("Append %d at end", periodMs);
+      lListAppend(&ctxt->timeoutHandlers, nent);
+   }
+   ctxt->baseTime = curTime;
+
+   return ret;
+}
+
+/**
+ * Create an application context
+ */
+struct LUECtxt *lueCtxtCreate()
+{
+   struct LUECtxt *lue;
+
+   lue = (struct LUECtxt *) malloc(sizeof(*lue));
+   assert(lue);
+   lListInit(&lue->fileHandlers);
+   lListInit(&lue->timeoutHandlers);
+   lListInit(&lue->fileRem);
+   lListInit(&lue->timeRem);
+
+   lue->baseTime = times(NULL);
+   lue->setTime = 0;
+   lue->timeSet = false;
+   lue->exiting = false;
+   
+   if (0 == clock_tick)
+      clock_tick = sysconf(_SC_CLK_TCK);
+   
+   return lue;
+}
+
+/**
+ * Destroy an application context
+ */
+void lueCtxtDestroy(struct LUECtxt *lue)
+{
+   lListPurge(&lue->fileHandlers);
+   lListPurge(&lue->timeoutHandlers);
+   free(lue);
+}
+
+/**
+ * Drive the timeouts ourself (from now on until an increment of -1)
+ * This is intended for use in testing frameworks
+ * Caveat emptor: Currently, interactions with the scheduler (agent) API is undefined.
+ *                Not for use in lues that use the agent scheduler
+ * @param ctxt LUElication context object
+ * @param mSecs Ms to advance. Use -1 to return to realtime
+ */
+void lueTimeAdvance(struct LUECtxt *ctxt, int mSecs)
+{
+   // Obviously we are executing a callback right now (arent we always)
+   // The time leap is taken into account before falling back into poll() below
+   if (mSecs >= 0)
+   {
+      if (!ctxt->timeSet)
+      {
+         ctxt->timeSet = true;
+         ctxt->setTime = times(NULL) + mSecs;
+      }
+      else
+      {
+         ctxt->setTime += mSecs;
+      }
+   }
+   else if (mSecs == -1)
+   {
+      // Go back to realtime
+      ctxt->timeSet = false;
+      ctxt->baseTime += times(NULL) - ctxt->setTime;
+      ctxt->setTime = 0;
+   }
+}
+
+/**
+ * Run the application
+ */
+void lueRun(struct LUECtxt *ctxt)
+{
+   struct LUETimerH     *timer;
+   int            pollRet;
+
+   do
+   {
+      clock_t        curTime;
+      int            curPeriod = 0;
+
+      // Do due timers
+      if (lListHead(&ctxt->timeoutHandlers))
+      {
+         curTime = ctxt->timeSet ? ctxt->setTime : times(NULL);
+         curPeriod = (curTime - ctxt->baseTime) / clock_tick * 1000
+                  + ((curTime - ctxt->baseTime) % clock_tick) * 1000 / clock_tick;
+         Debug("Period for timer execution %d", curPeriod);
+         while((timer = lListHead(&ctxt->timeoutHandlers)) &&
+               timer->dueTime <= curPeriod)
+         {
+            timer->handler(ctxt, timer, timer->data);
+            lueRemTimer(ctxt, timer);
+
+            // baseTime changes for every lueAddTimer
+            curPeriod = (curTime - ctxt->baseTime) / clock_tick * 1000
+                + ((curTime - ctxt->baseTime) % clock_tick) * 1000 / clock_tick;
+         }
+         lListPurge(&ctxt->timeRem); // Reap timer zombies
+      }
+
+      // Calculate waiting time
+      if (ctxt->exiting)
+         curPeriod = 0;
+      else if ((timer = lListHead(&ctxt->timeoutHandlers)) &&
+               timer->dueTime > curPeriod)
+      {
+         Debug("Period from timer head %d - %d -> %d",
+               timer->dueTime, curPeriod, timer->dueTime - curPeriod);
+         curPeriod = timer->dueTime - curPeriod;
+      }
+      else if (NULL != timer)
+         curPeriod = 0;
+      else
+         curPeriod = -1;
+
+      // Do pipe handlers
+      pollRet = 0;
+      if (lListHead(&ctxt->fileHandlers) && !ctxt->exiting)
+      {
+         struct pollfd  polls[lListLength(&ctxt->fileHandlers)];
+         struct LUEFileEventH *ent;
+
+         int ix = 0;
+         lListForeachIn(ent, &ctxt->fileHandlers)
+         {
+            ent->pollIx = ix;
+            polls[ix].fd = ent->fd;
+            polls[ix].events = LUE_FHIN == ent->direction ? POLLIN : POLLOUT;
+            polls[ix].revents = 0;
+            ix++;
+         }
+         Debug("Polling %d fds in %d ms", ix, curPeriod);
+         pollRet = poll(polls, ix, curPeriod);
+         if (pollRet < 0)
+         {
+            if (EINTR == errno)
+               continue;
+            else if (EBADF == errno)
+            {
+               lListForeachIn(ent, &ctxt->fileHandlers)
+               {
+                  if (fcntl(ent->fd, F_GETFD) == -1 && EBADF == errno)
+                  {
+                     ent->handler(ctxt, ent, ent->fd, ent->data);
+                  }
+               }
+            }
+            else
+            {
+               // Error in poll. Cannot continue
+               assert(false);
+               return;
+            }
+         }
+         else if (pollRet > 0)
+         {
+            lListForeachIn(ent, &ctxt->fileHandlers)
+            {
+               if (ent->handler && ent->pollIx >= 0 && polls[ent->pollIx].revents)
+               {
+                  ent->handler(ctxt, ent, ent->fd, ent->data);
+               }
+            }
+         }
+         if (lListHead(&ctxt->fileRem))
+         {
+            struct LUEFileEventH *ent;
+
+            while (NULL != (ent = lListHead(&ctxt->fileRem)))
+            {
+               lListRemove(&ctxt->fileHandlers, ent);
+               free(ent);
+            }
+         }
+      }
+      else if (curPeriod > 0)
+         poll(NULL, 0, curPeriod);
+      else
+         break; // LUEarently were out of work!
+   } while (!ctxt->exiting);
+            // Wont exit while there is due timers or files
+            //((timer = lListHead(&ctxt->timeoutHandlers)) &&
+            //timer->dueTime <= 0) || pollRet > 0);
+   Debug("LUE exiting - bye");
+}
+
+/**
+ * Terminate the application
+ */
+void lueExit(struct LUECtxt *ctxt)
+{
+   ctxt->exiting = true;
+}
+
+// vim: set ts=8 sw=3 sts=3 et: