path: root/camel/camel-operation.c

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#ifdef ENABLE_THREADS
#include <pthread.h>
#endif

#include <sys/time.h>
#include <unistd.h>

#include <glib.h>
#include "camel-operation.h"
#include "e-util/e-msgport.h"

#define d(x)

/* ********************************************************************** */

struct _status_stack {
    guint32 flags;
    char *msg;
    int pc;             /* last pc reported */
    unsigned int stamp;     /* last stamp reported */
};

struct _CamelOperation {
    pthread_t id;       /* id of running thread */
    guint32 flags;      /* cancelled ? */
    int blocked;        /* cancellation blocked depth */
    int refcount;

    CamelOperationStatusFunc status;
    void *status_data;
    unsigned int status_update;

    /* stack of status messages (struct _status_stack *) */
    GSList *status_stack;
    struct _status_stack *lastreport;

#ifdef ENABLE_THREADS
    EMsgPort *cancel_port;
    int cancel_fd;
#endif
};

#define CAMEL_OPERATION_CANCELLED (1<<0)
#define CAMEL_OPERATION_TRANSIENT (1<<1)

/* Delay before a transient operation has any effect on the status */
#define CAMEL_OPERATION_TRANSIENT_DELAY (5)

#ifdef ENABLE_THREADS
#define CAMEL_ACTIVE_LOCK() pthread_mutex_lock(&operation_active_lock)
#define CAMEL_ACTIVE_UNLOCK() pthread_mutex_unlock(&operation_active_lock)
static pthread_mutex_t operation_active_lock = PTHREAD_MUTEX_INITIALIZER;
#else
#define CAMEL_ACTIVE_LOCK()
#define CAMEL_ACTIVE_UNLOCK()
#endif

static unsigned int stamp (void);

static GHashTable *operation_active;

typedef struct _CamelOperationMsg {
    EMsg msg;
} CamelOperationMsg ;

/**
 * camel_operation_new:
 * @status: Callback for receiving status messages.
 * @status_data: User data.
 * 
 * Create a new camel operation handle.  Camel operation handles can
 * be used in a multithreaded application (or a single operation
 * handle can be used in a non threaded appliation) to cancel running
 * operations and to obtain notification messages of the internal
 * status of messages.
 * 
 * Return value: A new operation handle.
 **/
CamelOperation *camel_operation_new(CamelOperationStatusFunc status, void *status_data)
{
    CamelOperation *cc;

    cc = g_malloc0(sizeof(*cc));

    cc->flags = 0;
    cc->blocked = 0;
    cc->refcount = 1;
    cc->status = status;
    cc->status_data = status_data;
#ifdef ENABLE_THREADS
    cc->id = ~0;
    cc->cancel_port = e_msgport_new();
    cc->cancel_fd = -1;
#endif

    return cc;
}

/* return the registered operation, or NULL if none registered */
/* need to unref when done with it */
CamelOperation *camel_operation_registered(void)
{
    CamelOperation *cc = NULL;

    CAMEL_ACTIVE_LOCK();
    if (operation_active != NULL
        && (cc = g_hash_table_lookup(operation_active, (void *)pthread_self()))) {
        g_assert(cc->refcount > 0);
        cc->refcount++;
    }
    CAMEL_ACTIVE_UNLOCK();

    return cc;
}

/**
 * camel_operation_reset:
 * @cc: 
 * 
 * Resets an operation cancel state and message.
 **/
void camel_operation_reset(CamelOperation *cc)
{
    GSList *n;

#ifdef ENABLE_THREADS
    CamelOperationMsg *msg;

    while ((msg = (CamelOperationMsg *)e_msgport_get(cc->cancel_port)))
        g_free(msg);
#endif

    n = cc->status_stack;
    while (n) {
        g_free(n->data);
        n = n->next;
    }
    g_slist_free(cc->status_stack);
    cc->status_stack = NULL;

    cc->flags = 0;
    cc->blocked = 0;
}

/**
 * camel_operation_ref:
 * @cc: 
 * 
 * Add a reference to the CamelOperation @cc.
 **/
void camel_operation_ref(CamelOperation *cc)
{
    g_assert(cc->refcount > 0);

    CAMEL_ACTIVE_LOCK();
    cc->refcount++;
    CAMEL_ACTIVE_UNLOCK();
}

/**
 * camel_operation_unref:
 * @cc: 
 * 
 * Unref and potentially free @cc.
 **/
void camel_operation_unref(CamelOperation *cc)
{
    GSList *n;

    g_assert(cc->refcount > 0);

    CAMEL_ACTIVE_LOCK();
    if (cc->refcount == 1) {
#ifdef ENABLE_THREADS
        CamelOperationMsg *msg;

        while ((msg = (CamelOperationMsg *)e_msgport_get(cc->cancel_port)))
            g_free(msg);

        e_msgport_destroy(cc->cancel_port);
#endif

        if (cc->id != (~0)) {
            g_warning("Unreffing operation status which was still registered: %p\n", cc);
            g_hash_table_remove(operation_active, (void *)cc->id);
        }

        n = cc->status_stack;
        while (n) {
            g_warning("Camel operation status stack non empty: %s", (char *)n->data);
            g_free(n->data);
            n = n->next;
        }
        g_slist_free(cc->status_stack);

        g_free(cc);
    } else {
        cc->refcount--;
    }
    CAMEL_ACTIVE_UNLOCK();
}

/**
 * camel_operation_cancel_block:
 * @cc: 
 * 
 * Block cancellation for this operation.  If @cc is NULL, then the
 * current thread is blocked.
 **/
void camel_operation_cancel_block(CamelOperation *cc)
{
    CAMEL_ACTIVE_LOCK();
    if (operation_active == NULL)
        operation_active = g_hash_table_new(NULL, NULL);

    if (cc == NULL)
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());

    if (cc)
        cc->blocked++;
    CAMEL_ACTIVE_UNLOCK();
}

/**
 * camel_operation_cancel_unblock:
 * @cc: 
 * 
 * Unblock cancellation, when the unblock count reaches the block
 * count, then this operation can be cancelled.  If @cc is NULL, then
 * the current thread is unblocked.
 **/
void camel_operation_cancel_unblock(CamelOperation *cc)
{
    CAMEL_ACTIVE_LOCK();
    if (operation_active == NULL)
        operation_active = g_hash_table_new(NULL, NULL);

    if (cc == NULL)
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());

    if (cc)
        cc->blocked--;
    CAMEL_ACTIVE_UNLOCK();
}

static void
cancel_thread(void *key, CamelOperation *cc, void *data)
{
    CamelOperationMsg *msg;

    if (cc) {
        d(printf("cancelling thread %d\n", cc->id));

        cc->flags |= CAMEL_OPERATION_CANCELLED;
        msg = g_malloc0(sizeof(*msg));
        e_msgport_put(cc->cancel_port, (EMsg *)msg);
    }
}

/**
 * camel_operation_cancel:
 * @cc: 
 * 
 * Cancel a given operation.  If @cc is NULL then all outstanding
 * operations are cancelled.
 **/
void camel_operation_cancel(CamelOperation *cc)
{
    CamelOperationMsg *msg;
    
    CAMEL_ACTIVE_LOCK();

    if (cc == NULL) {
        if (operation_active) {
            g_hash_table_foreach(operation_active, (GHFunc)cancel_thread, NULL);
        }
    } else if ((cc->flags & CAMEL_OPERATION_CANCELLED) == 0) {
        d(printf("cancelling thread %d\n", cc->id));

        cc->flags |= CAMEL_OPERATION_CANCELLED;
        msg = g_malloc0(sizeof(*msg));
        e_msgport_put(cc->cancel_port, (EMsg *)msg);
    }

    CAMEL_ACTIVE_UNLOCK();
}

/**
 * camel_operation_register:
 * @cc: 
 * 
 * Register a thread or the main thread for cancellation through @cc.
 * If @cc is NULL, then a new cancellation is created for this thread,
 * but may only be cancelled from the same thread.
 *
 * All calls to operation_register() should be matched with calls to
 * operation_unregister(), or resources will be lost.
 **/
void camel_operation_register(CamelOperation *cc)
{
    pthread_t id = pthread_self();

    CAMEL_ACTIVE_LOCK();

    if (operation_active == NULL)
        operation_active = g_hash_table_new(NULL, NULL);

    if (cc == NULL) {
        cc = g_hash_table_lookup(operation_active, (void *)id);
        if (cc == NULL) {
            cc = camel_operation_new(NULL, NULL);
        }
    }

    if (cc->id == (~0)) {
        cc->id = id;
        g_hash_table_insert(operation_active, (void *)id, cc);
    } else {
        g_warning("Re-registering thread %lu for cancellation as thread %lu", cc->id, id);
    }

    d(printf("registering thread %ld for cancellation\n", id));

    CAMEL_ACTIVE_UNLOCK();
}

/**
 * camel_operation_unregister:
 * @cc: 
 * 
 * Unregister a given operation from being cancelled.  If @cc is NULL,
 * then the current thread is used.
 **/
void camel_operation_unregister(CamelOperation *cc)
{
    CAMEL_ACTIVE_LOCK();

    if (operation_active == NULL)
        operation_active = g_hash_table_new(NULL, NULL);

    if (cc == NULL) {
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());
        if (cc == NULL) {
            g_warning("Trying to unregister a thread that was never registered for cancellation");
        }
    }

    if (cc) {
        if (cc->id != (~0)) {
            g_hash_table_remove(operation_active, (void *)cc->id);
            cc->id = ~0;
        } else {
            g_warning("Unregistering an operation that was already unregistered");
        }
    }

    CAMEL_ACTIVE_UNLOCK();

    d({if (cc) printf("unregistering thread %d for cancellation\n", cc->id);});
}

/**
 * camel_operation_cancel_check:
 * @cc: 
 * 
 * Check if cancellation has been applied to @cc.  If @cc is NULL,
 * then the CamelOperation registered for the current thread is used.
 * 
 * Return value: TRUE if the operation has been cancelled.
 **/
gboolean camel_operation_cancel_check(CamelOperation *cc)
{
    CamelOperationMsg *msg;
    int cancelled;

    d(printf("checking for cancel in thread %d\n", pthread_self()));

    CAMEL_ACTIVE_LOCK();

    if (cc == NULL && operation_active)
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());

    if (cc == NULL || cc->blocked > 0) {
        d(printf("ahah!  cancellation is blocked\n"));
        cancelled = FALSE;
    } else if (cc->flags & CAMEL_OPERATION_CANCELLED) {
        d(printf("previously cancelled\n"));
        cancelled = TRUE;
    } else if ((msg = (CamelOperationMsg *)e_msgport_get(cc->cancel_port))) {
        d(printf("Got cancellation message\n"));
        g_free(msg);
        cc->flags |= CAMEL_OPERATION_CANCELLED;
        cancelled = TRUE;
    } else
        cancelled = FALSE;

    CAMEL_ACTIVE_UNLOCK();

    return cancelled;
}

/**
 * camel_operation_cancel_fd:
 * @cc: 
 * 
 * Retrieve a file descriptor that can be waited on (select, or poll)
 * for read, to asynchronously detect cancellation.
 * 
 * Return value: The fd, or -1 if cancellation is not available
 * (blocked, or has not been registered for this thread).
 **/
int camel_operation_cancel_fd(CamelOperation *cc)
{
    CAMEL_ACTIVE_LOCK();

    if (cc == NULL && operation_active) {
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());
    }

    if (cc == NULL
        || cc->blocked) {
        CAMEL_ACTIVE_UNLOCK();
        return -1;
    }

    if (cc->cancel_fd == -1)
        cc->cancel_fd = e_msgport_fd(cc->cancel_port);

    CAMEL_ACTIVE_UNLOCK();

    return cc->cancel_fd;
}

/**
 * camel_operation_start:
 * @cc: 
 * @what: 
 * @: 
 * 
 * Report the start of an operation.  All start operations should have
 * similar end operations.
 **/
void camel_operation_start(CamelOperation *cc, char *what, ...)
{
    va_list ap;
    char *msg;
    struct _status_stack *s;

    if (operation_active == NULL)
        return;

    CAMEL_ACTIVE_LOCK();

    if (cc == NULL)
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());

    if (cc == NULL || cc->status == NULL) {
        CAMEL_ACTIVE_UNLOCK();
        return;
    }

    va_start(ap, what);
    msg = g_strdup_vprintf(what, ap);
    va_end(ap);
    cc->status_update = 0;
    s = g_malloc0(sizeof(*s));
    s->msg = msg;
    s->flags = 0;
    cc->lastreport = s;
    cc->status_stack = g_slist_prepend(cc->status_stack, s);

    CAMEL_ACTIVE_UNLOCK();

    cc->status(cc, msg, CAMEL_OPERATION_START, cc->status_data);

    d(printf("start '%s'\n", msg, pc));
}

/**
 * camel_operation_start_transient:
 * @cc: 
 * @what: 
 * @: 
 * 
 * Start a transient event.  We only update this to the display if it
 * takes very long to process, and if we do, we then go back to the
 * previous state when finished.
 **/
void camel_operation_start_transient(CamelOperation *cc, char *what, ...)
{
    va_list ap;
    char *msg;
    struct _status_stack *s;

    if (operation_active == NULL)
        return;

    CAMEL_ACTIVE_LOCK();

    if (cc == NULL)
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());

    if (cc == NULL || cc->status == NULL) {
        CAMEL_ACTIVE_UNLOCK();
        return;
    }

    va_start(ap, what);
    msg = g_strdup_vprintf(what, ap);
    va_end(ap);
    cc->status_update = 0;
    s = g_malloc0(sizeof(*s));
    s->msg = msg;
    s->flags = CAMEL_OPERATION_TRANSIENT;
    s->stamp = stamp();
    cc->status_stack = g_slist_prepend(cc->status_stack, s);
    d(printf("start '%s'\n", msg, pc));

    CAMEL_ACTIVE_UNLOCK();

    /* we dont report it yet */
    /*cc->status(cc, msg, CAMEL_OPERATION_START, cc->status_data);*/
}

static unsigned int stamp(void)
{
    struct timeval tv;

    gettimeofday(&tv, NULL);
    /* update 4 times/second */
    return (tv.tv_sec * 4) + tv.tv_usec / (1000000/4);
}

/**
 * camel_operation_progress:
 * @cc: Operation to report to.
 * @pc: Percent complete, 0 to 100.
 * 
 * Report progress on the current operation.  If @cc is NULL, then the
 * currently registered operation is used.  @pc reports the current
 * percentage of completion, which should be in the range of 0 to 100.
 *
 * If the total percentage is not know, then use
 * camel_operation_progress_count().
 **/
void camel_operation_progress(CamelOperation *cc, int pc)
{
    unsigned int now;
    struct _status_stack *s;
    char *msg = NULL;

    if (operation_active == NULL)
        return;

    CAMEL_ACTIVE_LOCK();

    if (cc == NULL)
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());

    if (cc == NULL || cc->status == NULL || cc->status_stack == NULL) {
        CAMEL_ACTIVE_UNLOCK();
        return;
    }

    s = cc->status_stack->data;
    s->pc = pc;

    /* Transient messages dont start updating till 4 seconds after
       they started, then they update every second */
    now = stamp();
    if (cc->status_update == now) {
        cc = NULL;
    } else if (s->flags & CAMEL_OPERATION_TRANSIENT) {
        if (s->stamp + CAMEL_OPERATION_TRANSIENT_DELAY > now) {
            cc = NULL;
        } else {
            cc->status_update = now;
            cc->lastreport = s;
            msg = g_strdup(s->msg);
        }
    } else {
        s->stamp = cc->status_update = now;
        cc->lastreport = s;
        msg = g_strdup(s->msg);
    }

    CAMEL_ACTIVE_UNLOCK();

    if (cc) {
        cc->status(cc, msg, pc, cc->status_data);
        g_free(msg);
    }
}

void camel_operation_progress_count(CamelOperation *cc, int sofar)
{
    camel_operation_progress(cc, sofar);
}

/**
 * camel_operation_end:
 * @cc: 
 * @what: Format string.
 * @: 
 * 
 * Report the end of an operation.  If @cc is NULL, then the currently
 * registered operation is notified.
 **/
void camel_operation_end(CamelOperation *cc)
{
    struct _status_stack *s, *p;
    unsigned int now;
    char *msg = NULL;
    int pc = 0;

    if (operation_active == NULL)
        return;

    CAMEL_ACTIVE_LOCK();

    if (cc == NULL)
        cc = g_hash_table_lookup(operation_active, (void *)pthread_self());

    if (cc == NULL || cc->status == NULL || cc->status_stack == NULL) {
        CAMEL_ACTIVE_UNLOCK();
        return;
    }

    /* so what we do here is this.  If the operation that just
     * ended was transient, see if we have any other transient
     * messages that haven't been updated yet above us, otherwise,
     * re-update as a non-transient at the last reported pc */
    now = stamp();
    s = cc->status_stack->data;
    if (s->flags & CAMEL_OPERATION_TRANSIENT) {
        if (cc->lastreport == s) {
            GSList *l = cc->status_stack->next;
            while (l) {
                p = l->data;
                if (p->flags & CAMEL_OPERATION_TRANSIENT) {
                    if (p->stamp + CAMEL_OPERATION_TRANSIENT_DELAY < now) {
                        msg = g_strdup(p->msg);
                        pc = p->pc;
                        cc->lastreport = p;
                        break;
                    }
                } else {
                    msg = g_strdup(p->msg);
                    pc = p->pc;
                    cc->lastreport = p;
                    break;
                }
                l = l->next;
            }
        }
        g_free(s->msg);
    } else {
        msg = s->msg;
        pc = CAMEL_OPERATION_END;
        cc->lastreport = s;
    }
    g_free(s);
    cc->status_stack = g_slist_remove_link(cc->status_stack, cc->status_stack);

    CAMEL_ACTIVE_UNLOCK();

    if (msg) {
        cc->status(cc, msg, pc, cc->status_data);
        g_free(msg);
    }
}