duktape-1.5.2/src-separate/duk_api_heap.c

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/*
 *  Heap creation and destruction
 */
 
#include "duk_internal.h"
 
DUK_EXTERNAL
duk_context *duk_create_heap(duk_alloc_function alloc_func,
                             duk_realloc_function realloc_func,
                             duk_free_function free_func,
                             void *heap_udata,
                             duk_fatal_function fatal_handler) {
    duk_heap *heap = NULL;
    duk_context *ctx;
 
    /* Assume that either all memory funcs are NULL or non-NULL, mixed
     * cases will now be unsafe.
     */
 
    /* XXX: just assert non-NULL values here and make caller arguments
     * do the defaulting to the default implementations (smaller code)?
     */
 
    if (!alloc_func) {
        DUK_ASSERT(realloc_func == NULL);
        DUK_ASSERT(free_func == NULL);
#if defined(DUK_USE_PROVIDE_DEFAULT_ALLOC_FUNCTIONS)
        alloc_func = duk_default_alloc_function;
        realloc_func = duk_default_realloc_function;
        free_func = duk_default_free_function;
#else
        DUK_D(DUK_DPRINT("no allocation functions given and no default providers"));
        return NULL;
#endif
    } else {
        DUK_ASSERT(realloc_func != NULL);
        DUK_ASSERT(free_func != NULL);
    }
 
    if (!fatal_handler) {
        fatal_handler = duk_default_fatal_handler;
    }
 
    DUK_ASSERT(alloc_func != NULL);
    DUK_ASSERT(realloc_func != NULL);
    DUK_ASSERT(free_func != NULL);
    DUK_ASSERT(fatal_handler != NULL);
 
    heap = duk_heap_alloc(alloc_func, realloc_func, free_func, heap_udata, fatal_handler);
    if (!heap) {
        return NULL;
    }
    ctx = (duk_context *) heap->heap_thread;
    DUK_ASSERT(ctx != NULL);
    DUK_ASSERT(((duk_hthread *) ctx)->heap != NULL);
    return ctx;
}
 
DUK_EXTERNAL void duk_destroy_heap(duk_context *ctx) {
    duk_hthread *thr = (duk_hthread *) ctx;
    duk_heap *heap;
 
    if (!ctx) {
        return;
    }
    heap = thr->heap;
    DUK_ASSERT(heap != NULL);
 
    duk_heap_free(heap);
}
 
/* XXX: better place for this */
DUK_EXTERNAL void duk_set_global_object(duk_context *ctx) {
    duk_hthread *thr = (duk_hthread *) ctx;
    duk_hobject *h_glob;
    duk_hobject *h_prev_glob;
    duk_hobject *h_env;
    duk_hobject *h_prev_env;
 
    DUK_D(DUK_DPRINT("replace global object with: %!T", duk_get_tval(ctx, -1)));
 
    h_glob = duk_require_hobject(ctx, -1);
    DUK_ASSERT(h_glob != NULL);
 
    /*
     *  Replace global object.
     */
 
    h_prev_glob = thr->builtins[DUK_BIDX_GLOBAL];
    DUK_UNREF(h_prev_glob);
    thr->builtins[DUK_BIDX_GLOBAL] = h_glob;
    DUK_HOBJECT_INCREF(thr, h_glob);
    DUK_HOBJECT_DECREF_ALLOWNULL(thr, h_prev_glob);  /* side effects, in theory (referenced by global env) */
 
    /*
     *  Replace lexical environment for global scope
     *
     *  Create a new object environment for the global lexical scope.
     *  We can't just reset the _Target property of the current one,
     *  because the lexical scope is shared by other threads with the
     *  same (initial) built-ins.
     */
 
    (void) duk_push_object_helper(ctx,
                                  DUK_HOBJECT_FLAG_EXTENSIBLE |
                                  DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJENV),
                                  -1);  /* no prototype, updated below */
 
    duk_dup(ctx, -2);
    duk_dup(ctx, -3);
 
    /* [ ... new_glob new_env new_glob new_glob ] */
 
    duk_xdef_prop_stridx(thr, -3, DUK_STRIDX_INT_TARGET, DUK_PROPDESC_FLAGS_NONE);
    duk_xdef_prop_stridx(thr, -2, DUK_STRIDX_INT_THIS, DUK_PROPDESC_FLAGS_NONE);
 
    /* [ ... new_glob new_env ] */
 
    h_env = duk_get_hobject(ctx, -1);
    DUK_ASSERT(h_env != NULL);
 
    h_prev_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
    thr->builtins[DUK_BIDX_GLOBAL_ENV] = h_env;
    DUK_HOBJECT_INCREF(thr, h_env);
    DUK_HOBJECT_DECREF_ALLOWNULL(thr, h_prev_env);  /* side effects */
    DUK_UNREF(h_env);  /* without refcounts */
    DUK_UNREF(h_prev_env);
 
    /* [ ... new_glob new_env ] */
 
    duk_pop_2(ctx);
 
    /* [ ... ] */
}