#include "moar.h"

/* Handles loading of bytecode, including triggering the deserialize and load

 * special frames. Takes place in two steps, with a callback between them which

 * is triggered by the special_return mechanism. */

static void run_load(MVMThreadContext *tc, void *sr_data);

static void mark_sr_data(MVMThreadContext *tc, MVMFrame *frame, MVMGCWorklist *worklist) {

    MVM_gc_worklist_add(tc, worklist, &frame->special_return_data);

}

static void run_comp_unit(MVMThreadContext *tc, MVMCompUnit *cu) {

    /* If there's a deserialization frame, need to run that. */

    if (cu->body.deserialize_frame) {

        /* Set up special return to delegate to running the load frame,

         * if any. */

        tc->cur_frame->return_value             = NULL;

        tc->cur_frame->return_type              = MVM_RETURN_VOID;

        tc->cur_frame->special_return           = run_load;

        tc->cur_frame->special_return_data      = cu;

        tc->cur_frame->mark_special_return_data = mark_sr_data;

        /* Invoke the deserialization frame and return to the runloop. */

        MVM_frame_invoke(tc, cu->body.deserialize_frame, MVM_callsite_get_common(tc, MVM_CALLSITE_ID_NULL_ARGS),

            NULL, NULL, NULL, -1);

    }

    else {

        /* No deserialize frame, so do load frame instead. */

        run_load(tc, cu);

    }

}

void MVM_load_bytecode_buffer(MVMThreadContext *tc, MVMObject *buf) {

    MVMCompUnit *cu;

    MVMuint8    *data_start;

    MVMuint32    data_size;

    /* Ensure the source is in the correct form. */

    if (

        !IS_CONCRETE(buf)

        || REPR(buf)->ID != MVM_REPR_ID_VMArray

        || (

               ((MVMArrayREPRData *)STABLE(buf)->REPR_data)->slot_type != MVM_ARRAY_U8

            && ((MVMArrayREPRData *)STABLE(buf)->REPR_data)->slot_type != MVM_ARRAY_I8

        )

    )

        MVM_exception_throw_adhoc(tc, "loadbytecodebuffer requires a native int8 or uint8 array to read from");

    /* MVMCompUnit expects the data to be non-GC managed as it usually comes straight from a file */

    data_size = ((MVMArray *)buf)->body.elems;

    data_start = MVM_malloc(data_size);

    memcpy(data_start, (MVMuint8 *)(((MVMArray *)buf)->body.slots.i8 + ((MVMArray *)buf)->body.start), data_size);

    cu = MVM_cu_from_bytes(tc, data_start, data_size);

    run_comp_unit(tc, cu);

}

void MVM_load_bytecode(MVMThreadContext *tc, MVMString *filename) {

    MVMCompUnit *cu;

    MVMLoadedCompUnitName *loaded_name;

    /* Work out actual filename to use, taking --libpath into account. */

    filename = MVM_file_in_libpath(tc, filename);

    /* See if we already loaded this. */

    uv_mutex_lock(&tc->instance->mutex_loaded_compunits);

    MVM_tc_set_ex_release_mutex(tc, &tc->instance->mutex_loaded_compunits);

    MVM_HASH_GET(tc, tc->instance->loaded_compunits, filename, loaded_name);

    if (loaded_name) {

        /* already loaded */

        goto LEAVE;

    }

    /* Otherwise, load from disk. */

    MVMROOT(tc, filename, {

        char *c_filename = MVM_string_utf8_c8_encode_C_string(tc, filename);

        /* XXX any exception from MVM_cu_map_from_file needs to be handled

         *     and c_filename needs to be freed */

        cu = MVM_cu_map_from_file(tc, c_filename);

        MVM_free(c_filename);

        cu->body.filename = filename;

        run_comp_unit(tc, cu);

        loaded_name = MVM_calloc(1, sizeof(MVMLoadedCompUnitName));

        loaded_name->filename = filename;

        MVM_HASH_BIND(tc, tc->instance->loaded_compunits, filename, loaded_name);

    });

LEAVE:

    MVM_tc_clear_ex_release_mutex(tc);

    uv_mutex_unlock(&tc->instance->mutex_loaded_compunits);

}

void MVM_load_bytecode_fh(MVMThreadContext *tc, MVMObject *oshandle, MVMString *filename) {

    MVMCompUnit *cu;

    if (REPR(oshandle)->ID != MVM_REPR_ID_MVMOSHandle)

        MVM_exception_throw_adhoc(tc, "loadbytecodefh requires an object with REPR MVMOSHandle");

    MVMROOT(tc, filename, {

        MVMuint64 pos = MVM_io_tell(tc, oshandle);

        cu = MVM_cu_map_from_file_handle(tc, MVM_io_fileno(tc, oshandle), pos);

        cu->body.filename = filename;

        run_comp_unit(tc, cu);

    });

}

/* Callback after running deserialize code to run the load code. */

static void run_load(MVMThreadContext *tc, void *sr_data) {

    MVMCompUnit *cu = (MVMCompUnit *)sr_data;

    /* If there's a load frame, need to run that. If not, we're done. */

    if (cu->body.load_frame) {

        /* Make sure the call happens in void context. No special return

         * handler here; we want to go back to the place that used the

         * loadbytecode op in the first place. */

        tc->cur_frame->return_value = NULL;

        tc->cur_frame->return_type  = MVM_RETURN_VOID;

        /* Invoke the load frame and return to the runloop. */

        MVM_frame_invoke(tc, cu->body.load_frame, MVM_callsite_get_common(tc, MVM_CALLSITE_ID_NULL_ARGS),

            NULL, NULL, NULL, -1);

    }

}