duktape-1.5.2/src-separate/duk_hthread_misc.c

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/*
 *  Thread support.
 */
 
#include "duk_internal.h"
 
DUK_INTERNAL void duk_hthread_terminate(duk_hthread *thr) {
    DUK_ASSERT(thr != NULL);
 
    /* Order of unwinding is important */
 
    duk_hthread_catchstack_unwind(thr, 0);
 
    duk_hthread_callstack_unwind(thr, 0);  /* side effects, possibly errors */
 
    thr->valstack_bottom = thr->valstack;
    duk_set_top((duk_context *) thr, 0);  /* unwinds valstack, updating refcounts */
 
    thr->state = DUK_HTHREAD_STATE_TERMINATED;
 
    /* Here we could remove references to built-ins, but it may not be
     * worth the effort because built-ins are quite likely to be shared
     * with another (unterminated) thread, and terminated threads are also
     * usually garbage collected quite quickly.  Also, doing DECREFs
     * could trigger finalization, which would run on the current thread
     * and have access to only some of the built-ins.  Garbage collection
     * deals with this correctly already.
     */
 
    /* XXX: Shrink the stacks to minimize memory usage?  May not
     * be worth the effort because terminated threads are usually
     * garbage collected quite soon.
     */
}
 
DUK_INTERNAL duk_activation *duk_hthread_get_current_activation(duk_hthread *thr) {
    DUK_ASSERT(thr != NULL);
 
    if (thr->callstack_top > 0) {
        return thr->callstack + thr->callstack_top - 1;
    } else {
        return NULL;
    }
}
 
#if defined(DUK_USE_DEBUGGER_SUPPORT)
DUK_INTERNAL duk_uint_fast32_t duk_hthread_get_act_curr_pc(duk_hthread *thr, duk_activation *act) {
    duk_instr_t *bcode;
 
    DUK_ASSERT(thr != NULL);
    DUK_ASSERT(act != NULL);
    DUK_UNREF(thr);
 
    /* XXX: store 'bcode' pointer to activation for faster lookup? */
    if (act->func && DUK_HOBJECT_IS_COMPILEDFUNCTION(act->func)) {
        bcode = DUK_HCOMPILEDFUNCTION_GET_CODE_BASE(thr->heap, (duk_hcompiledfunction *) (act->func));
        return (duk_uint_fast32_t) (act->curr_pc - bcode);
    }
    return 0;
}
#endif  /* DUK_USE_DEBUGGER_SUPPORT */
 
DUK_INTERNAL duk_uint_fast32_t duk_hthread_get_act_prev_pc(duk_hthread *thr, duk_activation *act) {
    duk_instr_t *bcode;
    duk_uint_fast32_t ret;
 
    DUK_ASSERT(thr != NULL);
    DUK_ASSERT(act != NULL);
    DUK_UNREF(thr);
 
    if (act->func && DUK_HOBJECT_IS_COMPILEDFUNCTION(act->func)) {
        bcode = DUK_HCOMPILEDFUNCTION_GET_CODE_BASE(thr->heap, (duk_hcompiledfunction *) (act->func));
        ret = (duk_uint_fast32_t) (act->curr_pc - bcode);
        if (ret > 0) {
            ret--;
        }
        return ret;
    }
    return 0;
}
 
/* Write bytecode executor's curr_pc back to topmost activation (if any). */
DUK_INTERNAL void duk_hthread_sync_currpc(duk_hthread *thr) {
    duk_activation *act;
 
    DUK_ASSERT(thr != NULL);
 
    if (thr->ptr_curr_pc != NULL) {
        /* ptr_curr_pc != NULL only when bytecode executor is active. */
        DUK_ASSERT(thr->callstack_top > 0);
        act = thr->callstack + thr->callstack_top - 1;
        act->curr_pc = *thr->ptr_curr_pc;
    }
}
 
DUK_INTERNAL void duk_hthread_sync_and_null_currpc(duk_hthread *thr) {
    duk_activation *act;
 
    DUK_ASSERT(thr != NULL);
 
    if (thr->ptr_curr_pc != NULL) {
        /* ptr_curr_pc != NULL only when bytecode executor is active. */
        DUK_ASSERT(thr->callstack_top > 0);
        act = thr->callstack + thr->callstack_top - 1;
        act->curr_pc = *thr->ptr_curr_pc;
        thr->ptr_curr_pc = NULL;
    }
}