system: add BEventLock

system/BEventLock.c

@@ -0,0 +1,138 @@
+/**
+ * @file BEventLock.c
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * This file is part of BadVPN.
+ * 
+ * BadVPN is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ * 
+ * BadVPN 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <misc/offset.h>
+#include <system/BEventLock.h>
+
+static void exec_job_handler (BEventLock *o)
+{
+    ASSERT(!LinkedList2_IsEmpty(&o->jobs))
+    DebugObject_Access(&o->d_obj);
+    
+    // get job
+    BEventLockJob *j = UPPER_OBJECT(LinkedList2_GetFirst(&o->jobs), BEventLockJob, pending_node);
+    ASSERT(j->pending)
+    
+    // call handler
+    j->handler(j->user);
+    return;
+}
+
+void BEventLock_Init (BEventLock *o, BPendingGroup *pg)
+{
+    // init jobs list
+    LinkedList2_Init(&o->jobs);
+    
+    // init exec job
+    BPending_Init(&o->exec_job, pg, (BPending_handler)exec_job_handler, o);
+    
+    DebugObject_Init(&o->d_obj);
+    DebugCounter_Init(&o->pending_ctr);
+}
+
+void BEventLock_Free (BEventLock *o)
+{
+    ASSERT(LinkedList2_IsEmpty(&o->jobs))
+    DebugCounter_Free(&o->pending_ctr);
+    DebugObject_Free(&o->d_obj);
+    
+    // free exec jobs
+    BPending_Free(&o->exec_job);
+}
+
+void BEventLockJob_Init (BEventLockJob *o, BEventLock *l, BEventLock_handler handler, void *user)
+{
+    // init arguments
+    o->l = l;
+    o->handler = handler;
+    o->user = user;
+    
+    // set not pending
+    o->pending = 0;
+    
+    DebugObject_Init(&o->d_obj);
+    DebugCounter_Increment(&l->pending_ctr);
+}
+
+void BEventLockJob_Free (BEventLockJob *o)
+{
+    BEventLock *l = o->l;
+    
+    DebugCounter_Decrement(&l->pending_ctr);
+    DebugObject_Free(&o->d_obj);
+    
+    if (o->pending) {
+        int was_first = (&o->pending_node == LinkedList2_GetFirst(&l->jobs));
+        
+        // remove from jobs list
+        LinkedList2_Remove(&l->jobs, &o->pending_node);
+        
+        // schedule/unschedule job
+        if (was_first) {
+            if (LinkedList2_IsEmpty(&l->jobs)) {
+                BPending_Unset(&l->exec_job);
+            } else {
+                BPending_Set(&l->exec_job);
+            }
+        }
+    }
+}
+
+void BEventLockJob_Wait (BEventLockJob *o)
+{
+    BEventLock *l = o->l;
+    ASSERT(!o->pending)
+    
+    // append to jobs
+    LinkedList2_Append(&l->jobs, &o->pending_node);
+    
+    // set pending
+    o->pending = 1;
+    
+    // schedule next job if needed
+    if (&o->pending_node == LinkedList2_GetFirst(&l->jobs)) {
+        BPending_Set(&l->exec_job);
+    }
+}
+
+void BEventLockJob_Release (BEventLockJob *o)
+{
+    BEventLock *l = o->l;
+    ASSERT(o->pending)
+    
+    int was_first = (&o->pending_node == LinkedList2_GetFirst(&l->jobs));
+    
+    // remove from jobs list
+    LinkedList2_Remove(&l->jobs, &o->pending_node);
+    
+    // set not pending
+    o->pending = 0;
+    
+    // schedule/unschedule job
+    if (was_first) {
+        if (LinkedList2_IsEmpty(&l->jobs)) {
+            BPending_Unset(&l->exec_job);
+        } else {
+            BPending_Set(&l->exec_job);
+        }
+    }
+}

system/BEventLock.h

@@ -0,0 +1,120 @@
+/**
+ * @file BEventLock.h
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * This file is part of BadVPN.
+ * 
+ * BadVPN is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ * 
+ * BadVPN 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * 
+ * @section DESCRIPTION
+ * 
+ * A FIFO lock for events using the job queue ({@link BPending}).
+ */
+
+#ifndef BADVPN_SYSTEM_BEVENTLOCK_H
+#define BADVPN_SYSTEM_BEVENTLOCK_H
+
+#include <misc/debugcounter.h>
+#include <structure/LinkedList2.h>
+#include <system/DebugObject.h>
+#include <system/BPending.h>
+
+/**
+ * Event context handler called when the lock job has acquired the lock
+ * after requesting the lock with {@link BEventLockJob_Wait}.
+ * The object was in waiting state.
+ * The object enters locked state before the handler is called.
+ * 
+ * @param user as in {@link BEventLockJob_Init}
+ */
+typedef void (*BEventLock_handler) (void *user);
+
+/**
+ * A FIFO lock for events using the job queue ({@link BPending}).
+ */
+typedef struct {
+    LinkedList2 jobs;
+    BPending exec_job;
+    DebugObject d_obj;
+    DebugCounter pending_ctr;
+} BEventLock;
+
+/**
+ * An object that can request a {@link BEventLock} lock.
+ */
+typedef struct {
+    BEventLock *l;
+    BEventLock_handler handler;
+    void *user;
+    int pending;
+    LinkedList2Node pending_node;
+    DebugObject d_obj;
+} BEventLockJob;
+
+/**
+ * Initializes the object.
+ * 
+ * @param o the object
+ * @param pg pending group
+ */
+void BEventLock_Init (BEventLock *o, BPendingGroup *pg);
+
+/**
+ * Frees the object.
+ * There must be no {@link BEventLockJob} objects using this lock
+ * (regardless of their state).
+ * 
+ * @param o the object
+ */
+void BEventLock_Free (BEventLock *o);
+
+/**
+ * Initializes the object.
+ * The object is initialized in idle state.
+ * 
+ * @param o the object
+ * @param l the lock
+ * @param handler handler to call when the lock is aquired
+ * @param user value to pass to handler
+ */
+void BEventLockJob_Init (BEventLockJob *o, BEventLock *l, BEventLock_handler handler, void *user);
+
+/**
+ * Frees the object.
+ * 
+ * @param o the object
+ */
+void BEventLockJob_Free (BEventLockJob *o);
+
+/**
+ * Requests the lock.
+ * The object must be in idle state.
+ * The object enters waiting state.
+ * 
+ * @param o the object
+ */
+void BEventLockJob_Wait (BEventLockJob *o);
+
+/**
+ * Aborts the lock request or releases the lock.
+ * The object must be in waiting or locked state.
+ * The object enters idle state.
+ * 
+ * @param o the object
+ */
+void BEventLockJob_Release (BEventLockJob *o);
+
+#endif

system/CMakeLists.txt

@@ -20,6 +20,7 @@ add_library(system
     DebugObject.c
     BPending.c
     Listener.c
+    BEventLock.c
     ${BSYSTEM_ADDITIONAL_SOURCES}
 )
 target_link_libraries(system ${BSYSTEM_ADDITIONAL_LIBS})