mjs-sys 0.1.2

/*
 * Copyright (c) 2017 Cesanta Software Limited
 * All rights reserved
 */

#ifndef MJS_CORE_H
#define MJS_CORE_H

#include "mjs_ffi.h"
#include "mjs_gc.h"
#include "mjs_internal.h"

#if defined(__cplusplus)
extern "C" {
#endif /* __cplusplus */

#define JUMP_INSTRUCTION_SIZE 2

enum mjs_type {
  /* Primitive types */
  MJS_TYPE_UNDEFINED,
  MJS_TYPE_NULL,
  MJS_TYPE_BOOLEAN,
  MJS_TYPE_NUMBER,
  MJS_TYPE_STRING,
  MJS_TYPE_FOREIGN,

  /* Different classes of Object type */
  MJS_TYPE_OBJECT_GENERIC,
  MJS_TYPE_OBJECT_ARRAY,
  MJS_TYPE_OBJECT_FUNCTION,
  /*
   * TODO(dfrank): if we support prototypes, need to add items for them here
   */

  MJS_TYPES_CNT
};

enum mjs_call_stack_frame_item {
  CALL_STACK_FRAME_ITEM_RETVAL_STACK_IDX, /* TOS */
  CALL_STACK_FRAME_ITEM_LOOP_ADDR_IDX,
  CALL_STACK_FRAME_ITEM_SCOPE_IDX,
  CALL_STACK_FRAME_ITEM_RETURN_ADDR,
  CALL_STACK_FRAME_ITEM_THIS,

  CALL_STACK_FRAME_ITEMS_CNT
};

/*
 * A tag is made of the sign bit and the 4 lower order bits of byte 6.
 * So in total we have 32 possible tags.
 *
 * Tag (1,0) however cannot hold a zero payload otherwise it's interpreted as an
 * INFINITY; for simplicity we're just not going to use that combination.
 */
#define MAKE_TAG(s, t) \
  ((uint64_t)(s) << 63 | (uint64_t) 0x7ff0 << 48 | (uint64_t)(t) << 48)

#define MJS_TAG_OBJECT MAKE_TAG(1, 1)
#define MJS_TAG_FOREIGN MAKE_TAG(1, 2)
#define MJS_TAG_UNDEFINED MAKE_TAG(1, 3)
#define MJS_TAG_BOOLEAN MAKE_TAG(1, 4)
#define MJS_TAG_NAN MAKE_TAG(1, 5)
#define MJS_TAG_STRING_I MAKE_TAG(1, 6)  /* Inlined string len < 5 */
#define MJS_TAG_STRING_5 MAKE_TAG(1, 7)  /* Inlined string len 5 */
#define MJS_TAG_STRING_O MAKE_TAG(1, 8)  /* Owned string */
#define MJS_TAG_STRING_F MAKE_TAG(1, 9)  /* Foreign string */
#define MJS_TAG_STRING_C MAKE_TAG(1, 10) /* String chunk */
#define MJS_TAG_STRING_D MAKE_TAG(1, 11) /* Dictionary string  */
#define MJS_TAG_ARRAY MAKE_TAG(1, 12)
#define MJS_TAG_FUNCTION MAKE_TAG(1, 13)
#define MJS_TAG_FUNCTION_FFI MAKE_TAG(1, 14)
#define MJS_TAG_NULL MAKE_TAG(1, 15)

#define MJS_TAG_MASK MAKE_TAG(1, 15)

struct mjs_vals {
  /* Current `this` value  */
  mjs_val_t this_obj;
  mjs_val_t dataview_proto;

  /*
   * The object against which the last `OP_GET` was invoked. Needed for
   * "method invocation pattern".
   */
  mjs_val_t last_getprop_obj;
};

struct mjs_bcode_part {
  /* Global index of the bcode part */
  size_t start_idx;

  /* Actual bcode data */
  struct {
    const char *p; /* Memory chunk pointer */
    size_t len;    /* Memory chunk length */
  } data;

  /*
   * Result of evaluation (not parsing: if there is an error during parsing,
   * the bcode is not even committed). It is used to determine whether we
   * need to evaluate the file: if file was already evaluated, and the result
   * was MJS_OK, then we won't evaluate it again. Otherwise, we will.
   */
  mjs_err_t exec_res : 4;

  /* If set, bcode data does not need to be freed */
  unsigned in_rom : 1;
};

struct mjs {
  struct mbuf bcode_gen;
  struct mbuf bcode_parts;
  size_t bcode_len;
  struct mbuf stack;
  struct mbuf call_stack;
  struct mbuf arg_stack;
  struct mbuf scopes;          /* Scope objects */
  struct mbuf loop_addresses;  /* Addresses for breaks & continues */
  struct mbuf owned_strings;   /* Sequence of (varint len, char data[]) */
  struct mbuf foreign_strings; /* Sequence of (varint len, char *data) */
  struct mbuf owned_values;
  struct mbuf json_visited_stack;
  struct mjs_vals vals;
  char *error_msg;
  char *stack_trace;
  enum mjs_err error;
  mjs_ffi_resolver_t *dlsym;  /* Symbol resolver function for FFI */
  ffi_cb_args_t *ffi_cb_args; /* List of FFI args descriptors */
  size_t cur_bcode_offset;

  struct gc_arena object_arena;
  struct gc_arena property_arena;
  struct gc_arena ffi_sig_arena;

  unsigned inhibit_gc : 1;
  unsigned need_gc : 1;
  unsigned generate_jsc : 1;
};

/*
 * Bcode header: type of the items, and item numbers.
 */
typedef uint32_t mjs_header_item_t;
enum mjs_header_items {
  MJS_HDR_ITEM_TOTAL_SIZE,   /* Total size of the bcode (not counting the
                                OP_BCODE_HEADER byte) */
  MJS_HDR_ITEM_BCODE_OFFSET, /* Offset to the start of the actual bcode (not
                                counting the OP_BCODE_HEADER byte) */
  MJS_HDR_ITEM_MAP_OFFSET,   /* Offset to the start of offset-to-line_no mapping
                                k*/

  MJS_HDR_ITEMS_CNT
};

MJS_PRIVATE size_t mjs_get_func_addr(mjs_val_t v);

MJS_PRIVATE int mjs_getretvalpos(struct mjs *mjs);

MJS_PRIVATE enum mjs_type mjs_get_type(mjs_val_t v);

/*
 * Prints stack trace starting from the given bcode offset; other offsets
 * (if any) will be fetched from the call_stack.
 */
MJS_PRIVATE void mjs_gen_stack_trace(struct mjs *mjs, size_t offset);

MJS_PRIVATE mjs_val_t vtop(struct mbuf *m);
MJS_PRIVATE size_t mjs_stack_size(const struct mbuf *m);
MJS_PRIVATE mjs_val_t *vptr(struct mbuf *m, int idx);
MJS_PRIVATE void push_mjs_val(struct mbuf *m, mjs_val_t v);
MJS_PRIVATE mjs_val_t mjs_pop_val(struct mbuf *m);
MJS_PRIVATE mjs_val_t mjs_pop(struct mjs *mjs);
MJS_PRIVATE void mjs_push(struct mjs *mjs, mjs_val_t v);
MJS_PRIVATE void mjs_die(struct mjs *mjs);

#if defined(__cplusplus)
}
#endif /* __cplusplus */

#endif /* MJS_CORE_H */