/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim:set expandtab ts=4 shiftwidth=4: */
/* 
 * Copyright (c) 2008, 2010 Oracle and/or its affiliates, Inc. All rights
 * reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 * Authors: Lin Ma <lin.ma@sun.com>
 */

#include "config.h"
#include <rctl.h>
#include <strings.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <glib.h>
#include "fen-kernel.h"
#include "fen-dump.h"

#ifdef GIO_COMPILATION
#define FK_W if (FALSE) g_debug
#else
#include "gam_error.h"
#define FK_W(...) GAM_DEBUG(DEBUG_INFO, __VA_ARGS__)
#endif

G_LOCK_DEFINE (fen_lock);

static ulong max_port_events = 512;
static GList *pn_visible_list;	/* the queue of ports which don't have the max objs */
static GQueue *g_eventq = NULL;
static timespec_t zero_wait;
static void (*user_process_events_cb) (gpointer, node_event_t*);
static port_event_t *pevents = NULL;
static gint PE_ALLOC = 2048;
static GHashTable *renamed_hash = NULL; /* <parent node, ev> */

typedef struct _PSource {
    GSource  source;            /* Inherit from GSource, must be the first. */
    GPollFD  gfd;
    gboolean pending;
    uint_t   event_growing_factor;
    uint_t   pending_events;
} PSource;

#define PGPFD(s)             (&((PSource *)(s))->gfd)
#define SLEEP_BASE_TIME      10	/* in milliseconds */
#define EXPECT_INC_EVENTS(pn)  (1 << (pn->event_growing_factor))

#define RENAME_EVENTS_INTERVAL 500 /* in milliseconds */
#define PROCESS_PORT_EVENTS_TIME 1000 /* in milliseconds */
guint process_port_event_id = 0;

static gchar* _event_strings(int event);
static const gchar* _event_string (int event);
static GSource *psource_new();

static gboolean port_prepare(GSource *source, gint *timeout_);
static gboolean port_check(GSource *source);
static gboolean port_dispatch(GSource *source, GSourceFunc callback, gpointer user_data);
static GSourceFuncs fen_source_func = {
    port_prepare,
    port_check,
    port_dispatch,
    NULL
};

static gboolean
port_prepare(GSource *source, gint *timeout_)
{
    return FALSE;
}

static gboolean
port_check(GSource *source)
{
	PSource *pn = (PSource *)source;
    uint_t nget;
    
    if (pn->pending) {
        pn->pending = FALSE;
        g_source_add_poll(source, PGPFD(source));
        g_source_unref(source);
        return FALSE;
    }

    if (!(PGPFD(pn)->revents & G_IO_IN))
        return FALSE;

    if (port_getn(PGPFD(source)->fd, NULL, 0, &nget, 0) == 0) {
        if (nget - pn->pending_events > EXPECT_INC_EVENTS(pn)) {
            /* Sleep for a while. */
            pn->pending_events = nget;
            pn->event_growing_factor ++;

            pn->pending = TRUE;
            g_source_ref(source);
            g_source_remove_poll(source, PGPFD(source));
            g_timeout_add(SLEEP_BASE_TIME,
              (GSourceFunc)port_check,
              (gpointer)pn);
            return FALSE;
        }
    }

    pn->pending_events = 0;
    pn->event_growing_factor = 0;

    return TRUE;
}

static gboolean
port_dispatch(GSource *source, GSourceFunc callback, gpointer user_data)
{
    node_t *f;
	uint_t nget = 0;
	uint_t total = 0;

    FK_W ("%s 0x%p fd %d\n", __func__, source, PGPFD(source)->fd);

    G_LOCK (fen_lock);
    do {
        nget = 1;
        if (port_getn(PGPFD(source)->fd, pevents, PE_ALLOC, &nget, &zero_wait) == 0) {
            int i;
            for (i = 0; i < nget; i++) {
                f = (node_t *)pevents[i].portev_user;

                if (pevents[i].portev_source == PORT_SOURCE_FILE) {

                    NODE_CLE_STATE(f, NODE_STATE_ASSOCIATED);
                    NODE_SET_STATE(f, NODE_STATE_HAS_EVENTS);

                    if (HAS_NO_EXCEPTION_EVENTS(pevents[i].portev_events)) {
                        /* If the events do not show it's deleted, update
                         * file timestamp to avoid missing events next time.
                         */
                        if (node_lstat(f) != 0 /* || port_add(f) != 0 */) {
                            /* Included deleted event. */
                            pevents[i].portev_events |= FILE_DELETE;
                        }
                    }

                    /* Queue it and waiting for processing. */
                    g_queue_push_tail(g_eventq,
                      node_event_new(pevents[i].portev_events, (gpointer)f));

                } else {
                    FK_W ("[kernel] unknown portev_source %d\n", pevents[i].portev_source);
                }
            }

            total += nget;

        } else {
            FK_W ("[kernel] port_getn %s\n", g_strerror (errno));
            break;
        }
    } while (nget == PE_ALLOC);

    G_UNLOCK (fen_lock);

    if (total > 0 && callback) {
        FK_W ("[kernel] get total %ld events\n", total);
        return callback (user_data);
    }
    return TRUE;
}

static gboolean
process_renamed_hash_cb(gpointer key, gpointer value, gpointer user_data)
{
    node_event_t *ev = value;

#if 0
    node_add_event(ev->user_data, ev);
#else
    user_process_events_cb(ev->user_data, ev);
#endif
    /* Always delete self from hash. */
    return TRUE;
}

static gboolean
port_events_process_cb(gpointer user_data)
{
    node_event_t *ev;
    
    G_LOCK (fen_lock);

	/* Processing g_eventq */
    while ((ev = (node_event_t*)g_queue_pop_head (g_eventq)) != NULL) {

        /* FK_W ("[%s] 0x%p %s\n", __func__, ev, _event_string (ev->e)); */

        {
            gchar *log = _event_strings(ev->e);
            FK_W ("%s %s %s\n", __func__, NODE_NAME(ev->user_data), log);
            g_free(log);
        }

#ifdef GIO_COMPILATION
        /* Use the parent node as a hash, because only the dir_subs in the
         * parent node should receive MOVE event.
         */
        if (NODE_PARENT(ev->user_data)) {
            if (ev->e == FILE_RENAME_TO) {
                g_hash_table_insert(renamed_hash, NODE_PARENT(ev->user_data), ev);
                g_time_val_add(&ev->rename_tv, RENAME_EVENTS_INTERVAL);
                continue;
            }
            if (ev->e == FILE_RENAME_FROM) {
                node_event_t *pair_ev;

                pair_ev = g_hash_table_lookup(renamed_hash, NODE_PARENT(ev->user_data));
                if (pair_ev && node_timeval_lt(&ev->ctv, &pair_ev->rename_tv)) {
                    g_hash_table_remove(renamed_hash, NODE_PARENT(ev->user_data));
                    pair_ev->pair_data = ev->user_data;
                    /* Free ev, exchange pair_ev and ev. */
                    node_event_delete(ev);
                    ev = pair_ev;
                }
            }
        }
#endif
    
#if 0
        node_add_event(ev->user_data, ev);
#else
        user_process_events_cb(ev->user_data, ev);
#endif
    }

    /* Processing the events in renamed_hash. TODO we should delay it and wait
     * for more possible pair.
     */
    g_hash_table_foreach_remove(renamed_hash, process_renamed_hash_cb, NULL);

    G_UNLOCK (fen_lock);

    process_port_event_id = 0;
    return FALSE;
}

static gboolean
port_events_read_cb(gpointer user_data)
{

    if (process_port_event_id == 0) {
        process_port_event_id = g_timeout_add(PROCESS_PORT_EVENTS_TIME,
          port_events_process_cb,
          NULL);
    }

	return TRUE;
}

/*
 * malloc PSource and port_create, start thread at pnode_ref.
 * if psource_new succeeded, the PSource will never
 * be freed. So PSource can be freed only in psource_new.
 * Note pnode_monitor_remove_all can also free PSource, but currently no one
 * invork it.
 */
static GSource*
psource_new()
{
    GSource *source = NULL;
    int fd;

    if ((fd = port_create()) >= 0) {
        source = g_source_new(&fen_source_func, sizeof(PSource));
        PGPFD(source)->fd = fd;
        PGPFD(source)->events = G_IO_IN | G_IO_HUP | G_IO_ERR;
        g_source_set_callback(source, port_events_read_cb, NULL, NULL);
        g_source_attach(source, NULL);
        g_source_unref(source);
        g_source_add_poll(source, PGPFD(source));

        FK_W ("%s 0x%p fd %d\n", __func__, source, PGPFD(source)->fd);
    } else {
        FK_W ("PORT_CREATE %s\n", g_strerror(errno));
        g_return_val_if_reached(NULL);
    }

	return source;
}

/*
 * port_add:
 * @f:
 *
 * Unsafe, need lock fen_lock.
 * port_add will associate a GSource to @f->source
 */
gint
port_add(node_t *f)
{
	GSource *source = f->source;

    FK_W ("%s [0x%p] %s\n", __func__, f, NODE_NAME(f));

    g_assert(f);
    g_assert(NODE_HAS_FLAG(f, NODE_FLAG_STAT_UPDATED));

    /* if (!NODE_HAS_FLAG(f, NODE_FLAG_STAT_DONE)) { */
    /*     if (NODE_STAT(f) != 0) { */
    /*         return errno; */
    /*     } */
    /* } */

    /* Try re-use f->pn. f->pn may be used by other request, e.g. f is deleted
     * for a long time. So if pn is full, we try to open a new one.
     */
    if (!source) {
start_over:
        /* Try the next visible source. */
        if (pn_visible_list) {
            source = (GSource *)pn_visible_list->data;
        } else {
            if ((source = psource_new()) != NULL) {
                g_assert (g_list_find (pn_visible_list, source) == NULL);
                pn_visible_list = g_list_prepend (pn_visible_list, source);
            }
        }
    }

    if (port_associate(PGPFD(source)->fd, PORT_SOURCE_FILE, (uintptr_t)FILE_OBJECT(f),
        CONCERNED_EVENTS,
        (void *)f) == 0) {
        f->source = source;
        NODE_SET_STATE(f, NODE_STATE_ASSOCIATED);
        NODE_CLE_FLAG(f, NODE_FLAG_STAT_UPDATED);
        FK_W ("PORT_ASSOCIATE 0x%p OK\n", f);
        return 0;
    } else if (errno == EAGAIN) {
        /* Full, remove it. */
        pn_visible_list = g_list_remove (pn_visible_list, source);
        /* Re-add to port */
        goto start_over;

    } else if (errno == ENOENT) {
        /* File is not exist */
    } else if (errno == ENOTSUP) {
        /* FS is not supported. Currently we think it no longer make sense to
         * monitor it, so clean the stat info and return 0 to ignore this
         * node. If there are requirement, we can consider to add polling
         * method.
         */
        NODE_CLE_FLAG(f, NODE_FLAG_STAT_UPDATED);
        return 0;
    } else {
        FK_W ("PORT_ASSOCIATE 0x%p %s\n", f, g_strerror (errno));
    }

    /* No matter if associated successfully, stat info is out-of-date, so clean it. */
    NODE_CLE_FLAG(f, NODE_FLAG_STAT_UPDATED);
    return errno;
}

/*
 * port_remove
 *
 * < private >
 * Unsafe, need lock fen_lock.
 */
void
port_remove (node_t *f)
{
    /* g_assert(f->source); */

    if (NODE_HAS_STATE(f, NODE_STATE_ASSOCIATED)) {
        /* Mark unregisted. */
        if (port_dissociate(PGPFD(f->source)->fd, PORT_SOURCE_FILE, (uintptr_t)FILE_OBJECT(f)) == 0) {
            /*
             * Note, we can run foode_delete if dissociating is failed,
             * because there may be some pending events (mostly like
             * FILE_DELETE) in the port_get. If we delete the foode
             * the fnode may be deleted, then port_get will run on an invalid
             * address.
             */
            NODE_CLE_STATE(f, NODE_STATE_ASSOCIATED);
            FK_W ("PORT_DISSOCIATE 0x%p OK\n", f);
        } else if (errno == ENOENT) {
            /* The file has been removed from port, after port_get or before
             * port_get but DELETED event has been generated.
             * Ignored. */
        } else {
            FK_W ("PORT_DISSOCIATE 0x%p %s\n", f, g_strerror (errno));
            g_return_if_reached();
        }
    }
}

/*
 * Get Solaris resouce values.
 *
 */

extern gboolean
port_class_init (void (*user_process_events_callback) (gpointer, node_event_t*))
{
	rctlblk_t *rblk;

	if ((rblk = malloc (rctlblk_size ())) == NULL) {
        FK_W ("[kernel] rblk malloc %s\n", g_strerror (errno));
		return FALSE;
	}
	if (getrctl ("process.max-port-events", NULL, rblk, RCTL_FIRST) == -1) {
        FK_W ("[kernel] getrctl %s\n", g_strerror (errno));
        free (rblk);
        return FALSE;
	} else {
        max_port_events = rctlblk_get_value(rblk);
		FK_W ("max_port_events = %u\n", max_port_events);
        free (rblk);
	}
    renamed_hash = g_hash_table_new_full(g_direct_hash, g_direct_equal,
      NULL, NULL);
    if (renamed_hash == NULL) {
		FK_W ("[kernel] FEN global renamed queue initializing faild\n");
        return FALSE;
    }
    if ((g_eventq = g_queue_new ()) == NULL) {
		FK_W ("[kernel] FEN global event queue initializing faild\n");
        return FALSE;
    }
    if (user_process_events_callback == NULL) {
		FK_W ("[kernel] FEN global no user_process_events_callback\n");
        return FALSE;
    }
    user_process_events_cb = user_process_events_callback;
    memset (&zero_wait, 0, sizeof (timespec_t));

    pevents = g_malloc(PE_ALLOC * sizeof(port_event_t));
    if (pevents == NULL) {
		FK_W ("[kernel] FEN global alloc pevents failed\n");
        return FALSE;
    }

	return TRUE;
}

static gchar*
printevent (const char *pname, int event, const char *tag)
{
    static gchar	*event_string = NULL;
    GString			*str;

    g_free(event_string);

    str = g_string_new ("");
    g_string_printf (str, "[%s] [%-20s]", tag, pname);
    if (event & FILE_ACCESS) {
        str = g_string_append (str, " ACCESS");
    }
    if (event & FILE_MODIFIED) {
        str = g_string_append (str, " MODIFIED");
    }
    if (event & FILE_ATTRIB) {
        str = g_string_append (str, " ATTRIB");
    }
    if (event & FILE_DELETE) {
        str = g_string_append (str, " DELETE");
    }
    if (event & FILE_RENAME_TO) {
        str = g_string_append (str, " RENAME_TO");
    }
    if (event & FILE_RENAME_FROM) {
        str = g_string_append (str, " RENAME_FROM");
    }
    if (event & UNMOUNTED) {
        str = g_string_append (str, " UNMOUNTED");
    }
    if (event & MOUNTEDOVER) {
        str = g_string_append (str, " MOUNTEDOVER");
    }
    event_string = str->str;
    g_string_free (str, FALSE);
    return event_string;
}

static gchar *
_event_strings(int event)
{
    GString *str = g_string_sized_new(80);

    if (event & FILE_DELETE)
        g_string_append(str, " FILE_DELETE");

    if (event & FILE_RENAME_FROM)
        g_string_append(str, " FILE_RENAME_FROM");

    if (event & FILE_MODIFIED)
        g_string_append(str, " FILE_MODIFIED");

    if (event & FILE_RENAME_TO)
        g_string_append(str, " FILE_RENAME_TO");

    if (event & MOUNTEDOVER)
        g_string_append(str, " MOUNTEDOVER");

    if (event & FILE_ATTRIB)
        g_string_append(str, " FILE_ATTRIB");

    if (event & UNMOUNTED)
        g_string_append(str, " UNMOUNTED");

    if (event & FILE_ACCESS)
        g_string_append(str, " FILE_ACCESS");

    return g_string_free(str, FALSE);
}

static const gchar *
_event_string (int event)
{
    switch (event) {
    case FILE_DELETE:
        return "FILE_DELETE";
    case FILE_RENAME_FROM:
        return "FILE_RENAME_FROM";
    case FILE_MODIFIED:
        return "FILE_MODIFIED";
    case FILE_RENAME_TO:
        return "FILE_RENAME_TO";
    case MOUNTEDOVER:
        return "MOUNTEDOVER";
    case FILE_ATTRIB:
        return "FILE_ATTRIB";
    case UNMOUNTED:
        return "UNMOUNTED";
    case FILE_ACCESS:
        return "FILE_ACCESS";
    default:
        return "EVENT_UNKNOWN";
    }
}