Added a queue empty test in del_queue_thread().

[mpdm.git] / mpdm_v.c

/*

    MPDM - Minimum Profit Data Manager
    Copyright (C) 2003/2011 Angel Ortega <angel@triptico.com>

    mpdm_v.c - Basic value management

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    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 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

    http://www.triptico.com

*/

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <locale.h>

#include "mpdm.h"


/** data **/

/* control structure */

struct mpdm_control *mpdm = NULL;


/** code **/

static void cleanup_value(mpdm_t v)
/* cleans a value */
{
    /* collapse multiple values */
    if (v->flags & MPDM_MULTIPLE)
        mpdm_collapse(v, 0, v->size);

    /* free data if needed */
    if (v->data != NULL && v->flags & MPDM_FREE) {
        free((void *) v->data);
        v->data = NULL;
    }

    mpdm->count--;

    free(v);
}


static void destroy_value(mpdm_t v)
/* destroys a value */
{
    if (mpdm->threaded_delete) {
        /* atomically enqueue this value */
        mpdm_mutex_lock(mpdm->del_queue_mutex);

        v->next = mpdm->del;
        mpdm->del = v;

        mpdm_mutex_unlock(mpdm->del_queue_mutex);

        /* notify the del queue thread */
        mpdm_semaphore_post(mpdm->del_queue_sem);
    }
    else
        cleanup_value(v);
}


static mpdm_t del_queue_thread(mpdm_t args, mpdm_t ctxt)
/* delete queue processing thread */
{
    for (;;) {
        mpdm_t v;

        /* wait for next value */
        mpdm_semaphore_wait(mpdm->del_queue_sem);

        /* do nothing if the queue is empty (should't happen) */
        if (mpdm->del == NULL)
            continue;

        /* atomically dequeue */
        mpdm_mutex_lock(mpdm->del_queue_mutex);

        v = mpdm->del;
        mpdm->del = v->next;

        mpdm_mutex_unlock(mpdm->del_queue_mutex);

        cleanup_value(v);
    }
}


/**
 * mpdm_new - Creates a new value.
 * @flags: flags
 * @data: pointer to real data
 * @size: size of data
 *
 * Creates a new value. @flags is an or-ed set of flags, @data is a
 * pointer to the data the value will store and @size the size of these
 * data (if value is to be a multiple one, @size is a number of elements,
 * or a number of bytes otherwise).
 *
 * This function is normally not directly used; use any of the type
 * creation macros instead.
 * [Value Creation]
 */
mpdm_t mpdm_new(int flags, const void *data, int size)
{
    mpdm_t v = NULL;

    /* alloc */
    if ((v = malloc(sizeof(struct mpdm_val))) != NULL) {
        /* account one value more */
        mpdm->count++;

        v->flags    = flags;
        v->ref      = 0;
        v->data     = data;
        v->size     = size;
        v->next     = NULL;
    }

    return v;
}


/**
 * mpdm_ref - Increments the reference count of a value.
 * @v: the value
 *
 * Increments the reference count of a value.
 * [Value Management]
 */
mpdm_t mpdm_ref(mpdm_t v)
{
    if (v != NULL)
        v->ref++;

    return v;
}


/**
 * mpdm_unref - Decrements the reference count of a value.
 * @v: the value
 *
 * Decrements the reference count of a value. If the reference
 * count of the value reaches 0, it's destroyed.
 * [Value Management]
 */
mpdm_t mpdm_unref(mpdm_t v)
{
    if (v != NULL) {
        v->ref--;

        if (v->ref <= 0) {
            destroy_value(v);
            v = NULL;
        }
    }

    return v;
}


/**
 * mpdm_unrefnd - Decrements the reference count of a value, without destroy.
 * @v: the value
 *
 * Decrements the reference count of a value, without destroying
 * the value if it's unreferenced.
 * [Value Management]
 */
mpdm_t mpdm_unrefnd(mpdm_t v)
{
    if (v != NULL)
        v->ref--;

    return v;
}


/**
 * mpdm_size - Returns the size of an element.
 * @v: the element
 *
 * Returns the size of an element. It does not change the
 * reference count of the value.
 * [Value Management]
 */
int mpdm_size(const mpdm_t v)
{
    int r = 0;

    /* NULL values have no size */
    if (v != NULL)
        r = v->size;

    return r;
}


/**
 * mpdm_clone - Creates a clone of a value.
 * @v: the value
 *
 * Creates a clone of a value. If the value is multiple, a new value will
 * be created containing clones of all its elements; otherwise,
 * the same unchanged value is returned.
 * [Value Management]
 */
mpdm_t mpdm_clone(const mpdm_t v)
{
    mpdm_t r;

    mpdm_ref(v);

    if (MPDM_IS_ARRAY(v))
        r = mpdm_aclone(v);
    else
        r = v;

    mpdm_unref(v);

    return r;
}


/**
 * mpdm_root - Returns the root hash.
 *
 * Returns the root hash. This hash is stored internally and can be used
 * as a kind of global symbol table.
 * [Value Management]
 */
mpdm_t mpdm_root(void)
{
    if (mpdm->root == NULL)
        mpdm->root = mpdm_ref(MPDM_H(0));

    return mpdm->root;
}


/**
 * mpdm_set_ival - Sets the integer value.
 * @v: the value
 * @ival: the integer
 *
 * Sets the integer value for @v. It does not change
 * the reference count of @v.
 */
mpdm_t mpdm_set_ival(mpdm_t v, int ival)
/* sets an integer value to a value */
{
    v->flags    |= MPDM_IVAL;
    v->ival     = ival;

    return v;
}


/**
 * mpdm_set_rval - Sets the real value.
 * @v: the value
 * @rval: the real
 *
 * Sets the real value for @v. It does not change
 * the reference count of @v.
 */
mpdm_t mpdm_set_rval(mpdm_t v, double rval)
/* sets a real value to a value */
{
    v->flags    |= MPDM_RVAL;
    v->rval     = rval;

    return v;
}


/**
 * mpdm_void - Refs then unrefs a value.
 * @v: the value
 *
 * References and unreferences a value. To be used to receive
 * the output of mpdm_exec() in case of it being void (i.e.
 * its return value ignored).
 */
void mpdm_void(mpdm_t v)
{
    mpdm_ref(v);
    mpdm_unref(v);
}


/**
 * mpdm_is_null - Returns 1 if a value is NULL.
 * @v: the value
 *
 * Returns 1 if a value is NULL. The reference count is touched.
 */
int mpdm_is_null(mpdm_t v)
{
    int r;

    mpdm_ref(v);
    r = v == NULL ? 1 : 0;
    mpdm_unref(v);

    return r;
}


/**
 * mpdm_exec - Executes an executable value.
 * @c: the code value
 * @args: the arguments
 * @ctxt: the context
 *
 * Executes an executable value. If @c is a scalar value, its data
 * should be a pointer to a directly executable C function with a
 * prototype of mpdm_t func(mpdm_t args, mpdm_t ctxt); if it's a multiple
 * one, the first value's data should be a pointer to a directly executable
 * C function with a prototype of
 * mpdm_t func(mpdm_t b, mpdm_t args, mpdm_t ctxt) and
 * the second value will be passed as the @b argument. This value is used
 * to store bytecode or so when implementing virtual machines or compilers.
 * The @ctxt is meant to be used as a special context to implement local
 * symbol tables and such. Its meaning is free and can be NULL.
 *
 * Returns the return value of the code. If @c is NULL or not executable,
 * returns NULL.
 * [Value Management]
 */
mpdm_t mpdm_exec(mpdm_t c, mpdm_t args, mpdm_t ctxt)
{
    mpdm_t r = NULL;

    mpdm_ref(c);
    mpdm_ref(args);
    mpdm_ref(ctxt);

    if (c != NULL && (c->flags & MPDM_EXEC)) {

        if (c->flags & MPDM_MULTIPLE) {
            mpdm_t x;
            mpdm_t(*func) (mpdm_t, mpdm_t, mpdm_t);

            /* value is multiple; first element is the
               3 argument version of the executable function,
               next its optional additional information,
               the arguments and the context */
            x = mpdm_aget(c, 0);

            if ((func =
                 (mpdm_t(*)(mpdm_t, mpdm_t, mpdm_t)) (x->data)) != NULL)
                r = func(mpdm_aget(c, 1), args, ctxt);
        }
        else {
            mpdm_t(*func) (mpdm_t, mpdm_t);

            /* value is scalar; c is the 2 argument
               version of the executable function */
            if ((func = (mpdm_t(*)(mpdm_t, mpdm_t)) (c->data)) != NULL)
                r = func(args, ctxt);
        }
    }

    mpdm_unref(ctxt);
    mpdm_unref(args);
    mpdm_unref(c);

    return r;
}


mpdm_t mpdm_exec_1(mpdm_t c, mpdm_t a1, mpdm_t ctxt)
{
    mpdm_t r;
    mpdm_t a = MPDM_A(1);

    mpdm_ref(a);
    mpdm_aset(a, a1, 0);

    r = mpdm_exec(c, a, ctxt);

    mpdm_unref(a);

    return r;
}


mpdm_t mpdm_exec_2(mpdm_t c, mpdm_t a1, mpdm_t a2, mpdm_t ctxt)
{
    mpdm_t r;
    mpdm_t a = MPDM_A(2);

    mpdm_ref(a);
    mpdm_aset(a, a1, 0);
    mpdm_aset(a, a2, 1);

    r = mpdm_exec(c, a, ctxt);

    mpdm_unref(a);

    return r;
}


mpdm_t mpdm_exec_3(mpdm_t c, mpdm_t a1, mpdm_t a2, mpdm_t a3, mpdm_t ctxt)
{
    mpdm_t r;
    mpdm_t a = MPDM_A(3);

    mpdm_ref(a);
    mpdm_aset(a, a1, 0);
    mpdm_aset(a, a2, 1);
    mpdm_aset(a, a3, 2);

    r = mpdm_exec(c, a, ctxt);

    mpdm_unref(a);

    return r;
}


mpdm_t mpdm_xnew(mpdm_t(*a1) (mpdm_t, mpdm_t, mpdm_t), mpdm_t a2)
{
    mpdm_t x;

    x = MPDM_A(2);
    x->flags |= MPDM_EXEC;

    mpdm_ref(x);

    mpdm_aset(x, MPDM_X(a1), 0);
    mpdm_aset(x, a2, 1);

    mpdm_unrefnd(x);

    return x;
}


mpdm_t mpdm_new_copy(int flags, void *ptr, int size)
{
    mpdm_t r = NULL;

    if (ptr != NULL) {
        char *ptr2 = malloc(size);
        memcpy(ptr2, ptr, size);

        r = mpdm_new(MPDM_FREE | flags, ptr2, size);
    }

    return r;
}


static mpdm_t MPDM(const mpdm_t args, mpdm_t ctxt)
/* accesor / mutator for MPDM internal data */
{
    mpdm_t v;

    mpdm_ref(args);

    v = mpdm_aget(args, 0);

    if (v != NULL) {
        mpdm_t w;

        /* do changes */
        if ((w = mpdm_hget_s(v, L"hash_buckets")) != NULL)
            mpdm->hash_buckets = mpdm_ival(w);
        else
        if ((w = mpdm_hget_s(v, L"threaded_delete")) != NULL)
            mpdm->threaded_delete = mpdm_ival(w);
    }

    /* now collect all information */
    v = MPDM_H(0);

    mpdm_ref(v);

    mpdm_hset_s(v, L"version",          MPDM_MBS(VERSION));
    mpdm_hset_s(v, L"count",            MPDM_I(mpdm->count));
    mpdm_hset_s(v, L"hash_buckets",     MPDM_I(mpdm->hash_buckets));
    mpdm_hset_s(v, L"threaded_delete",  MPDM_I(mpdm->threaded_delete));

    mpdm_unref(args);

    mpdm_unrefnd(v);

    return v;
}

extern char **environ;

static mpdm_t build_env(void)
/* builds a hash with the environment */
{
    char **ptr;
    mpdm_t e = MPDM_H(0);

    mpdm_ref(e);

    for (ptr = environ; *ptr != NULL; ptr++) {
        char *eq = strchr(*ptr, '=');

        if (eq != NULL) {
            mpdm_t k, v;

            k = MPDM_NMBS((*ptr), eq - (*ptr));
            v = MPDM_MBS(eq + 1);

            mpdm_hset(e, k, v);
        }
    }

    mpdm_unrefnd(e);

    return e;
}


/**
 * mpdm_startup - Initializes MPDM.
 *
 * Initializes the Minimum Profit Data Manager. Returns 0 if
 * everything went OK.
 */
int mpdm_startup(void)
{
    /* do the startup only unless done beforehand */
    if (mpdm == NULL) {
        /* alloc space */
        if ((mpdm = malloc(sizeof(struct mpdm_control))) == NULL)
            return -1;

        /* cleans it */
        memset(mpdm, '\0', sizeof(struct mpdm_control));

        /* sets the defaults */
        mpdm->hash_buckets = 31;

        /* sets the threaded delete control */
        mpdm->threaded_delete = 0;

        /* create the threaded delete thread and control */
        mpdm->del_queue_mutex   = mpdm_new_mutex();
        mpdm->del_queue_sem     = mpdm_new_semaphore(0);
        mpdm_exec_thread(MPDM_X(del_queue_thread), NULL, NULL);

        /* sets the locale */
        if (setlocale(LC_ALL, "") == NULL)
            setlocale(LC_ALL, "C");

        mpdm_encoding(NULL);

        /* store the MPDM() function */
        mpdm_hset_s(mpdm_root(), L"MPDM", MPDM_X(MPDM));

        /* store the ENV hash */
        mpdm_hset_s(mpdm_root(), L"ENV", build_env());
    }

    /* everything went OK */
    return 0;
}


/**
 * mpdm_shutdown - Shuts down MPDM.
 *
 * Shuts down MPDM. No MPDM functions should be used from now on.
 */
void mpdm_shutdown(void)
{
    /* dummy, by now */
}

/**
 * MPDM_A - Creates an array value.
 * @n: Number of elements
 *
 * Creates a new array value with @n elements.
 * [Value Creation]
 */
/** mpdm_t MPDM_A(int n); */
/* ; */

/**
 * MPDM_H - Creates a hash value.
 * @n: Number of buckets in the hash (0: use default)
 *
 * Creates a new hash value with @n buckets. The number
 * of buckets must be a prime number. If @n is 0, an
 * optimal number of buckets will be used.
 * [Value Creation]
 */
/** mpdm_t MPDM_H(int n); */
/* ; */

/**
 * MPDM_LS - Creates a string value from a literal string.
 * @wcs: the wide character string
 *
 * Creates a new string value from a literal, wide character string.
 * A pointer to the string will be stored in the value (not a copy).
 * [Value Creation]
 */
/** mpdm_t MPDM_LS(wchar_t * wcs); */
/* ; */

/**
 * MPDM_S - Creates a string value from a string.
 * @wcs: the wide character string
 *
 * Creates a new string value from a wide character string. The value
 * will store a copy of the string that will be freed on destruction.
 * [Value Creation]
 */
/** mpdm_t MPDM_S(wchar_t * wcs); */
/* ; */

/**
 * MPDM_NS - Creates a string value from a string, with size.
 * @wcs: the wide character string
 * @s: the size in chars the string will hold
 *
 * Creates a new string value with a copy of the first @s characters
 * from the @wcs string.
 * [Value Creation]
 */
/** mpdm_t MPDM_NS(wchar_t * wcs, int s); */
/* ; */

/**
 * MPDM_ENS - Creates a string value from an external string, with size.
 * @wcs: the external wide character string
 * @s: the size in chars the string will hold
 *
 * Creates a new string value with size @s. The @wcs string must be
 * a dynamic value (i.e. allocated by malloc()) that will be freed on
 * destruction.
 * [Value Creation]
 */
/** mpdm_t MPDM_ENS(wchar_t * wcs, int s); */
/* ; */

/**
 * MPDM_I - Creates an integer value.
 * @i: the integer
 *
 * Creates a new integer value. MPDM integers are strings.
 * [Value Creation]
 */
/** mpdm_t MPDM_I(int i); */
/* ; */

/**
 * MPDM_R - Creates a real value.
 * @r: the real number
 *
 * Creates a new real value. MPDM integers are strings.
 * [Value Creation]
 */
/** mpdm_t MPDM_R(double r); */
/* ; */

/**
 * MPDM_F - Creates a file value.
 * @f: the file descriptor
 *
 * Creates a new file value.
 * [Value Creation]
 */
/** mpdm_t MPDM_F(FILE * f); */
/* ; */

/**
 * MPDM_MBS - Creates a string value from a multibyte string.
 * @mbs: the multibyte string
 *
 * Creates a new string value from a multibyte string, that will be
 * converted to wcs by mpdm_mbstowcs().
 * [Value Creation]
 */
/** mpdm_t MPDM_MBS(char * mbs); */
/* ; */

/**
 * MPDM_NMBS - Creates a string value from a multibyte string, with size.
 * @mbs: the multibyte string
 * @s: the size
 *
 * Creates a new string value with the first @s characters from the @mbs
 * multibyte string, that will be converted to wcs by mpdm_mbstowcs().
 * [Value Creation]
 */
/** mpdm_t MPDM_NMBS(char * mbs, int s); */
/* ; */

/**
 * MPDM_2MBS - Creates a multibyte string value from a wide char string.
 * @wcs: the wide char string
 *
 * Creates a multibyte string value from the @wcs wide char string,
 * converting it by mpdm_wcstombs(). Take note that multibyte string values
 * are not properly strings, so they cannot be used for string comparison
 * and such.
 * [Value Creation]
 */
/** mpdm_t MPDM_2MBS(wchar_t * wcs); */
/* ; */

/**
 * MPDM_X - Creates a new executable value.
 * @func: the C code function
 *
 * Creates a new executable value given a pointer to the @func C code function.
 * The function must receive an mpdm_t array value (that will hold their
 * arguments) and return another one.
 * [Value Creation]
 */
/** mpdm_t MPDM_X(mpdm_t (* func)(mpdm_t args)); */
/* ; */

/**
 * MPDM_C - Creates a new value with a copy of a buffer.
 * @flags: additional flags
 * @ptr: pointer to data
 * @size: data size
 *
 * Create a new value with a copy of a buffer. The value will store a copy
 * of @ptr and have the additional @flags.
 * [Value Creation]
 */
/** mpdm_t MPDM_C(int flags, void *ptr, int size); */
/* ; */

/**
 * MPDM_IS_ARRAY - Tests if a value is an array.
 * @v: the value
 *
 * Returns non-zero if @v is an array.
 */
/** int MPDM_IS_ARRAY(mpdm_t v); */
/* ; */

/**
 * MPDM_IS_HASH - Tests if a value is a hash.
 * @v: the value
 *
 * Returns non-zero if @v is a hash.
 */
/** int MPDM_IS_HASH(mpdm_t v); */
/* ; */

/**
 * MPDM_IS_EXEC - Tests if a value is executable.
 * @v: the value
 *
 * Returns non-zero if @v is executable.
 */
/** int MPDM_IS_EXEC(mpdm_t v); */
/* ; */

/**
 * MPDM_IS_STRING - Tests if a value is a string.
 * @v: the value
 *
 * Returns non-zero if @v is a string.
 */
/** int MPDM_IS_STRING(mpdm_t v); */
/* ; */