path: root/e-util/e-tree-memory.c

/*
 * This program 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) version 3.
 *
 * This program 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 the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Chris Lahey <clahey@ximian.com>
 *      Chris Toshok <toshok@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

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

#include "e-tree-memory.h"

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>

#include <libxml/parser.h>
#include <libxml/xmlmemory.h>

#include "e-xml-utils.h"

#define E_TREE_MEMORY_GET_PRIVATE(obj) \
    (G_TYPE_INSTANCE_GET_PRIVATE \
    ((obj), E_TYPE_TREE_MEMORY, ETreeMemoryPrivate))

G_DEFINE_TYPE (ETreeMemory, e_tree_memory, E_TYPE_TREE_MODEL)

enum {
    FILL_IN_CHILDREN,
    LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = { 0, };

typedef struct ETreeMemoryPath ETreeMemoryPath;

struct ETreeMemoryPath {
    gpointer         node_data;

    guint            children_computed : 1;

    /* parent/child/sibling pointers */
    ETreeMemoryPath *parent;
    ETreeMemoryPath *next_sibling;
    ETreeMemoryPath *prev_sibling;
    ETreeMemoryPath *first_child;
    ETreeMemoryPath *last_child;

    gint             num_children;
};

struct _ETreeMemoryPrivate {
    ETreeMemoryPath *root;

    /* whether nodes are created expanded
     * or collapsed by default */
    gboolean         expanded_default;

    gint             frozen;
    GFunc            destroy_func;
    gpointer         destroy_user_data;
};

/* ETreeMemoryPath functions */

static inline void
check_children (ETreeMemory *memory,
                ETreePath node)
{
    ETreeMemoryPath *path = node;
    if (!path->children_computed) {
        g_signal_emit (memory, signals[FILL_IN_CHILDREN], 0, node);
        path->children_computed = TRUE;
    }
}

static gint
e_tree_memory_path_depth (ETreeMemoryPath *path)
{
    gint depth = 0;

    g_return_val_if_fail (path != NULL, -1);

    for (path = path->parent; path; path = path->parent)
        depth++;
    return depth;
}

static void
e_tree_memory_path_insert (ETreeMemoryPath *parent,
                           gint position,
                           ETreeMemoryPath *child)
{
    g_return_if_fail (position <= parent->num_children && position >= -1);

    child->parent = parent;

    if (parent->first_child == NULL)
        parent->first_child = child;

    if (position == -1 || position == parent->num_children) {
        child->prev_sibling = parent->last_child;
        if (parent->last_child)
            parent->last_child->next_sibling = child;
        parent->last_child = child;
    } else {
        ETreeMemoryPath *c;
        for (c = parent->first_child; c; c = c->next_sibling) {
            if (position == 0) {
                child->next_sibling = c;
                child->prev_sibling = c->prev_sibling;

                if (child->next_sibling)
                    child->next_sibling->prev_sibling = child;
                if (child->prev_sibling)
                    child->prev_sibling->next_sibling = child;

                if (parent->first_child == c)
                    parent->first_child = child;
                break;
            }
            position--;
        }
    }

    parent->num_children++;
}

static void
e_tree_path_unlink (ETreeMemoryPath *path)
{
    ETreeMemoryPath *parent = path->parent;

    /* unlink first/last child if applicable */
    if (parent) {
        if (path == parent->first_child)
            parent->first_child = path->next_sibling;
        if (path == parent->last_child)
            parent->last_child = path->prev_sibling;

        parent->num_children--;
    }

    /* unlink prev/next sibling links */
    if (path->next_sibling)
        path->next_sibling->prev_sibling = path->prev_sibling;
    if (path->prev_sibling)
        path->prev_sibling->next_sibling = path->next_sibling;

    path->parent = NULL;
    path->next_sibling = NULL;
    path->prev_sibling = NULL;
}

/**
 * e_tree_memory_freeze:
 * @tree_memory: the ETreeModel to freeze.
 *
 * This function prepares an ETreeModel for a period of much change.
 * All signals regarding changes to the tree are deferred until we
 * thaw the tree.
 *
 **/
void
e_tree_memory_freeze (ETreeMemory *tree_memory)
{
    ETreeMemoryPrivate *priv = tree_memory->priv;

    if (priv->frozen == 0)
        e_tree_model_pre_change (E_TREE_MODEL (tree_memory));

    priv->frozen++;
}

/**
 * e_tree_memory_thaw:
 * @tree_memory: the ETreeMemory to thaw.
 *
 * This function thaws an ETreeMemory.  All the defered signals can add
 * up to a lot, we don't know - so we just emit a model_changed
 * signal.
 *
 **/
void
e_tree_memory_thaw (ETreeMemory *tree_memory)
{
    ETreeMemoryPrivate *priv = tree_memory->priv;

    if (priv->frozen > 0)
        priv->frozen--;
    if (priv->frozen == 0) {
        e_tree_model_node_changed (E_TREE_MODEL (tree_memory), priv->root);
    }
}

/* virtual methods */

static void
tree_memory_dispose (GObject *object)
{
    ETreeMemoryPrivate *priv;

    priv = E_TREE_MEMORY_GET_PRIVATE (object);

    if (priv->root)
        e_tree_memory_node_remove (
            E_TREE_MEMORY (object), priv->root);

    G_OBJECT_CLASS (e_tree_memory_parent_class)->dispose (object);
}

static ETreePath
tree_memory_get_root (ETreeModel *etm)
{
    ETreeMemoryPrivate *priv = E_TREE_MEMORY (etm)->priv;
    return priv->root;
}

static ETreePath
tree_memory_get_parent (ETreeModel *etm,
                 ETreePath node)
{
    ETreeMemoryPath *path = node;
    return path->parent;
}

static ETreePath
tree_memory_get_first_child (ETreeModel *etm,
                      ETreePath node)
{
    ETreeMemoryPath *path = node;

    check_children (E_TREE_MEMORY (etm), node);
    return path->first_child;
}

static ETreePath
tree_memory_get_last_child (ETreeModel *etm,
                     ETreePath node)
{
    ETreeMemoryPath *path = node;

    check_children (E_TREE_MEMORY (etm), node);
    return path->last_child;
}

static ETreePath
tree_memory_get_next (ETreeModel *etm,
               ETreePath node)
{
    ETreeMemoryPath *path = node;
    return path->next_sibling;
}

static ETreePath
tree_memory_get_prev (ETreeModel *etm,
               ETreePath node)
{
    ETreeMemoryPath *path = node;
    return path->prev_sibling;
}

static gboolean
tree_memory_is_root (ETreeModel *etm,
              ETreePath node)
{
    ETreeMemoryPath *path = node;
    return e_tree_memory_path_depth (path) == 0;
}

static gboolean
tree_memory_is_expandable (ETreeModel *etm,
                    ETreePath node)
{
    ETreeMemoryPath *path = node;

    check_children (E_TREE_MEMORY (etm), node);
    return path->first_child != NULL;
}

static guint
tree_memory_get_children (ETreeModel *etm,
                   ETreePath node,
                   ETreePath **nodes)
{
    ETreeMemoryPath *path = node;
    guint n_children;

    check_children (E_TREE_MEMORY (etm), node);

    n_children = path->num_children;

    if (nodes) {
        ETreeMemoryPath *p;
        gint i = 0;

        (*nodes) = g_new (ETreePath, n_children);
        for (p = path->first_child; p; p = p->next_sibling) {
            (*nodes)[i++] = p;
        }
    }

    return n_children;
}

static guint
tree_memory_depth (ETreeModel *etm,
            ETreePath path)
{
    return e_tree_memory_path_depth (path);
}

static gboolean
tree_memory_get_expanded_default (ETreeModel *etm)
{
    ETreeMemory *tree_memory = E_TREE_MEMORY (etm);
    ETreeMemoryPrivate *priv = tree_memory->priv;

    return priv->expanded_default;
}

static void
tree_memory_clear_children_computed (ETreeMemoryPath *path)
{
    for (path = path->first_child; path; path = path->next_sibling) {
        path->children_computed = FALSE;
        tree_memory_clear_children_computed (path);
    }
}

static void
tree_memory_node_request_collapse (ETreeModel *etm,
                            ETreePath node)
{
    ETreeModelClass *parent_class;

    if (node)
        tree_memory_clear_children_computed (node);

    parent_class = E_TREE_MODEL_CLASS (e_tree_memory_parent_class);

    if (parent_class->node_request_collapse != NULL)
        parent_class->node_request_collapse (etm, node);
}

static void
e_tree_memory_class_init (ETreeMemoryClass *class)
{
    GObjectClass *object_class;
    ETreeModelClass *tree_model_class;

    g_type_class_add_private (class, sizeof (ETreeMemoryPrivate));

    object_class = G_OBJECT_CLASS (class);
    object_class->dispose = tree_memory_dispose;

    tree_model_class = E_TREE_MODEL_CLASS (class);
    tree_model_class->get_root = tree_memory_get_root;
    tree_model_class->get_prev = tree_memory_get_prev;
    tree_model_class->get_next = tree_memory_get_next;
    tree_model_class->get_first_child = tree_memory_get_first_child;
    tree_model_class->get_last_child = tree_memory_get_last_child;
    tree_model_class->get_parent = tree_memory_get_parent;

    tree_model_class->is_root = tree_memory_is_root;
    tree_model_class->is_expandable = tree_memory_is_expandable;
    tree_model_class->get_children = tree_memory_get_children;
    tree_model_class->depth = tree_memory_depth;
    tree_model_class->get_expanded_default = tree_memory_get_expanded_default;

    tree_model_class->node_request_collapse = tree_memory_node_request_collapse;

    class->fill_in_children = NULL;

    signals[FILL_IN_CHILDREN] = g_signal_new (
        "fill_in_children",
        G_TYPE_FROM_CLASS (object_class),
        G_SIGNAL_RUN_LAST,
        G_STRUCT_OFFSET (ETreeMemoryClass, fill_in_children),
        (GSignalAccumulator) NULL, NULL,
        g_cclosure_marshal_VOID__POINTER,
        G_TYPE_NONE, 1,
        G_TYPE_POINTER);
}

static void
e_tree_memory_init (ETreeMemory *tree_memory)
{
    tree_memory->priv = E_TREE_MEMORY_GET_PRIVATE (tree_memory);
}

/**
 * e_tree_memory_construct:
 * @tree_memory:
 *
 *
 **/
void
e_tree_memory_construct (ETreeMemory *tree_memory)
{
}

/**
 * e_tree_memory_new
 *
 * XXX docs here.
 *
 * return values: a newly constructed ETreeMemory.
 */
ETreeMemory *
e_tree_memory_new (void)
{
    return g_object_new (E_TYPE_TREE_MEMORY, NULL);
}

/**
 * e_tree_memory_set_expanded_default
 *
 * Sets the state of nodes to be append to a thread.
 * They will either be expanded or collapsed, according to
 * the value of @expanded.
 */
void
e_tree_memory_set_expanded_default (ETreeMemory *tree_memory,
                                    gboolean expanded)
{
    g_return_if_fail (tree_memory != NULL);

    tree_memory->priv->expanded_default = expanded;
}

/**
 * e_tree_memory_node_get_data:
 * @tree_memory:
 * @node:
 *
 *
 *
 * Return value:
 **/
gpointer
e_tree_memory_node_get_data (ETreeMemory *tree_memory,
                             ETreePath node)
{
    ETreeMemoryPath *path = node;

    g_return_val_if_fail (path, NULL);

    return path->node_data;
}

/**
 * e_tree_memory_node_set_data:
 * @tree_memory:
 * @node:
 * @node_data:
 *
 *
 **/
void
e_tree_memory_node_set_data (ETreeMemory *tree_memory,
                             ETreePath node,
                             gpointer node_data)
{
    ETreeMemoryPath *path = node;

    g_return_if_fail (path);

    path->node_data = node_data;
}

/**
 * e_tree_memory_node_insert:
 * @tree_memory:
 * @parent_node:
 * @position:
 * @node_data:
 *
 *
 *
 * Return value:
 **/
ETreePath
e_tree_memory_node_insert (ETreeMemory *tree_memory,
                           ETreePath parent_node,
                           gint position,
                           gpointer node_data)
{
    ETreeMemoryPrivate *priv;
    ETreeMemoryPath *new_path;
    ETreeMemoryPath *parent_path = parent_node;

    g_return_val_if_fail (tree_memory != NULL, NULL);

    priv = tree_memory->priv;

    g_return_val_if_fail (parent_path != NULL || priv->root == NULL, NULL);

    priv = tree_memory->priv;

    if (!tree_memory->priv->frozen)
        e_tree_model_pre_change (E_TREE_MODEL (tree_memory));

    new_path = g_slice_new0 (ETreeMemoryPath);

    new_path->node_data = node_data;
    new_path->children_computed = FALSE;

    if (parent_path != NULL) {
        e_tree_memory_path_insert (parent_path, position, new_path);
        if (!tree_memory->priv->frozen)
            e_tree_model_node_inserted (
                E_TREE_MODEL (tree_memory),
                parent_path, new_path);
    } else {
        priv->root = new_path;
        if (!tree_memory->priv->frozen)
            e_tree_model_node_changed (
                E_TREE_MODEL (tree_memory), new_path);
    }

    return new_path;
}

/**
 * e_tree_memory_node_insert_before:
 * @tree_memory:
 * @parent:
 * @sibling:
 * @node_data:
 *
 *
 *
 * Return value:
 **/
ETreePath
e_tree_memory_node_insert_before (ETreeMemory *tree_memory,
                                  ETreePath parent,
                                  ETreePath sibling,
                                  gpointer node_data)
{
    ETreeMemoryPath *child;
    ETreeMemoryPath *parent_path = parent;
    ETreeMemoryPath *sibling_path = sibling;
    gint position = 0;

    g_return_val_if_fail (tree_memory != NULL, NULL);

    if (sibling != NULL) {
        for (child = parent_path->first_child; child; child = child->next_sibling) {
            if (child == sibling_path)
                break;
            position++;
        }
    } else
        position = parent_path->num_children;
    return e_tree_memory_node_insert (tree_memory, parent, position, node_data);
}

/* just blows away child data, doesn't take into account unlinking/etc */
static void
child_free (ETreeMemory *tree_memory,
            ETreeMemoryPath *node)
{
    ETreeMemoryPath *child, *next;

    child = node->first_child;
    while (child) {
        next = child->next_sibling;
        child_free (tree_memory, child);
        child = next;
    }

    if (tree_memory->priv->destroy_func) {
        tree_memory->priv->destroy_func (node->node_data, tree_memory->priv->destroy_user_data);
    }

    g_slice_free (ETreeMemoryPath, node);
}

/**
 * e_tree_memory_node_remove:
 * @tree_memory:
 * @path:
 *
 *
 *
 * Return value:
 **/
gpointer
e_tree_memory_node_remove (ETreeMemory *tree_memory,
                           ETreePath node)
{
    ETreeMemoryPath *path = node;
    ETreeMemoryPath *parent = path->parent;
    ETreeMemoryPath *sibling;
    gpointer ret = path->node_data;
    gint old_position = 0;

    g_return_val_if_fail (tree_memory != NULL, NULL);

    if (!tree_memory->priv->frozen) {
        e_tree_model_pre_change (E_TREE_MODEL (tree_memory));
        for (old_position = 0, sibling = path;
             sibling;
             old_position++, sibling = sibling->prev_sibling)
            /* Empty intentionally*/;
        old_position--;
    }

    /* unlink this node - we only have to unlink the root node being removed,
     * since the others are only references from this node */
    e_tree_path_unlink (path);

    /*printf("removing %d nodes from position %d\n", visible, base);*/
    if (!tree_memory->priv->frozen)
        e_tree_model_node_removed (E_TREE_MODEL (tree_memory), parent, path, old_position);

    child_free (tree_memory, path);

    if (path == tree_memory->priv->root)
        tree_memory->priv->root = NULL;

    if (!tree_memory->priv->frozen)
        e_tree_model_node_deleted (E_TREE_MODEL (tree_memory), path);

    return ret;
}

typedef struct {
    ETreeMemory *memory;
    gpointer closure;
    ETreeMemorySortCallback callback;
} MemoryAndClosure;

static gint
sort_callback (gconstpointer data1,
               gconstpointer data2,
               gpointer user_data)
{
    ETreePath path1 = *(ETreePath *) data1;
    ETreePath path2 = *(ETreePath *) data2;
    MemoryAndClosure *mac = user_data;
    return (*mac->callback) (mac->memory, path1, path2, mac->closure);
}

void
e_tree_memory_sort_node (ETreeMemory *tree_memory,
                         ETreePath node,
                         ETreeMemorySortCallback callback,
                         gpointer user_data)
{
    ETreeMemoryPath **children;
    ETreeMemoryPath *child;
    gint count;
    gint i;
    ETreeMemoryPath *path = node;
    MemoryAndClosure mac;
    ETreeMemoryPath *last;

    e_tree_model_pre_change (E_TREE_MODEL (tree_memory));

    i = 0;
    for (child = path->first_child; child; child = child->next_sibling)
        i++;

    children = g_new (ETreeMemoryPath *, i);

    count = i;

    for (child = path->first_child, i = 0;
         child;
         child = child->next_sibling, i++) {
        children[i] = child;
    }

    mac.memory = tree_memory;
    mac.closure = user_data;
    mac.callback = callback;

    g_qsort_with_data (
        children, count, sizeof (ETreeMemoryPath *),
        sort_callback, &mac);

    path->first_child = NULL;
    last = NULL;
    for (i = 0;
         i < count;
         i++) {
        children[i]->prev_sibling = last;
        if (last)
            last->next_sibling = children[i];
        else
            path->first_child = children[i];
        last = children[i];
    }
    if (last)
        last->next_sibling = NULL;

    path->last_child = last;

    g_free (children);

    e_tree_model_node_changed (E_TREE_MODEL (tree_memory), node);
}

void
e_tree_memory_set_node_destroy_func (ETreeMemory *tree_memory,
                                     GFunc destroy_func,
                                     gpointer user_data)
{
    tree_memory->priv->destroy_func = destroy_func;
    tree_memory->priv->destroy_user_data = user_data;
}