linguist/samples/C/fudge_node.c

/* Copyright (c) 2010 Jens Nyberg

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE. */

#include <fudge.h>
#include <kernel.h>
#include <modules/system/system.h>
#include "pipe.h"

static struct system_node root;
static struct system_node clone;

static unsigned int read(struct pipe_end *endself, struct pipe_end *endtarget, struct service_state *state, unsigned int count, void *buffer)
{

    count = buffer_rcfifo(&endself->buffer, count, buffer);

    if (!count && endtarget->node.refcount)
    {

        list_add(&endself->readlinks, &state->link);
        task_setstatus(state->link.data, TASK_STATUS_BLOCKED);

    }

    system_wakeup(&endtarget->writelinks);

    return count;

}

static unsigned int write(struct pipe_end *endself, struct pipe_end *endtarget, struct service_state *state, unsigned int count, void *buffer)
{

    count = buffer_wcfifo(&endtarget->buffer, count, buffer);

    if (!count)
    {

        list_add(&endself->writelinks, &state->link);
        task_setstatus(state->link.data, TASK_STATUS_BLOCKED);

    }

    system_wakeup(&endtarget->readlinks);

    return count;

}

static unsigned int end0_read(struct system_node *self, struct service_state *state, unsigned int count, void *buffer)
{

    struct pipe *pipe = (struct pipe *)self->parent;

    return read(&pipe->end0, &pipe->end1, state, count, buffer);

}

static unsigned int end0_write(struct system_node *self, struct service_state *state, unsigned int count, void *buffer)
{

    struct pipe *pipe = (struct pipe *)self->parent;

    return write(&pipe->end0, &pipe->end1, state, count, buffer);

}

static unsigned int end1_read(struct system_node *self, struct service_state *state, unsigned int count, void *buffer)
{

    struct pipe *pipe = (struct pipe *)self->parent;

    return read(&pipe->end1, &pipe->end0, state, count, buffer);

}

static unsigned int end1_write(struct system_node *self, struct service_state *state, unsigned int count, void *buffer)
{

    struct pipe *pipe = (struct pipe *)self->parent;

    return write(&pipe->end1, &pipe->end0, state, count, buffer);

}

static unsigned int clone_child(struct system_node *self, unsigned int count, char *path)
{

    struct list_item *current;

    for (current = root.children.head; current; current = current->next)
    {

        struct system_node *node = current->data;
        struct pipe *pipe = current->data;

        if (node == self)
            continue;

        if (pipe->end0.node.refcount || pipe->end1.node.refcount)
            continue;

        return node->child(node, count, path);

    }

    return 0;

}

void pipe_init(struct pipe *pipe)
{

    buffer_init(&pipe->end0.buffer, 4096, pipe->end0.data);
    buffer_init(&pipe->end1.buffer, 4096, pipe->end1.data);
    system_initnode(&pipe->end0.node, SYSTEM_NODETYPE_NORMAL, "0");
    system_initnode(&pipe->end1.node, SYSTEM_NODETYPE_NORMAL, "1");

    pipe->end0.node.read = end0_read;
    pipe->end0.node.write = end0_write;
    pipe->end1.node.read = end1_read;
    pipe->end1.node.write = end1_write;

    system_initnode(&pipe->root, SYSTEM_NODETYPE_GROUP | SYSTEM_NODETYPE_MULTI, "pipe");
    system_addchild(&pipe->root, &pipe->end0.node);
    system_addchild(&pipe->root, &pipe->end1.node);

}

void pipe_register(struct pipe *pipe)
{

    system_addchild(&root, &pipe->root);

}

void pipe_unregister(struct pipe *pipe)
{

    system_removechild(&root, &pipe->root);

}

void module_init(void)
{

    system_initnode(&root, SYSTEM_NODETYPE_GROUP, "pipe");
    system_initnode(&clone, SYSTEM_NODETYPE_GROUP, "clone");

    clone.child = clone_child;

    system_addchild(&root, &clone);

}

void module_register(void)
{

    system_registernode(&root);

}

void module_unregister(void)
{

    system_unregisternode(&root);

}