/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

parcel Lucy;

/** Base class for all objects.
 */

public class Clownfish::Obj {

    VTable *vtable;
    lucy_ref_t ref;

    /** Abstract initializer.
     */
    public inert Obj*
    init(Obj* self);

    /** Zero argument factory constructor.
     */
    public abstract incremented Obj*
    Make(Obj *self);

    /** Return an object's refcount.
     */
    uint32_t
    Get_RefCount(Obj *self);

    /** Increment an object's refcount.
     *
     * @return The object, allowing an assignment idiom.
     */
    incremented Obj*
    Inc_RefCount(Obj *self);

    /** NULL-safe invocation of Inc_RefCount().
     *
     * @return NULL if <code>self</code> is NULL, otherwise the return value
     * of Inc_RefCount().
     */
    inert inline incremented Obj*
    incref(Obj *self);

    /** Decrement an object's refcount, calling Destroy() if it hits 0.
     *
     * @return the modified refcount.
     */
    uint32_t
    Dec_RefCount(Obj *self);

    /** NULL-safe invocation of Dec_RefCount().
     *
     * @return NULL if <code>self</code> is NULL, otherwise the return value
     * of Dec_RefCount().
     */
    inert inline uint32_t
    decref(Obj *self);

    /** Return a host-language object wrapper for this object.
     */
    void*
    To_Host(Obj *self);

    /** Return a clone of the object.
     */
    public abstract incremented Obj*
    Clone(Obj *self);

    /** Generic destructor.  Frees the struct itself but not any complex
     * member elements.
     */
    public void
    Destroy(Obj *self);

    /** Invoke the Destroy() method found in <code>vtable</code> on
     * <code>self</code>.
     *
     * TODO: Eliminate this function if we can arrive at a proper SUPER syntax.
     */
    inert inline void
    super_destroy(Obj *self, VTable *vtable);

    /** Indicate whether two objects are the same.  By default, compares the
     * memory address.
     *
     * @param other Another Obj.
     */
    public bool_t
    Equals(Obj *self, Obj *other);

    /** Indicate whether one object is less than, equal to, or greater than
     * another.
     *
     * @param other Another Obj.
     * @return 0 if the objects are equal, a negative number if
     * <code>self</code> is less than <code>other</code>, and a positive
     * number if <code>self</code> is greater than <code>other</code>.
     */
    public abstract int32_t
    Compare_To(Obj *self, Obj *other);

    /** Return a hash code for the object -- by default, the memory address.
     */
    public int32_t
    Hash_Sum(Obj *self);

    /** Return the object's VTable.
     */
    public VTable*
    Get_VTable(Obj *self);

    /** Return the name of the class that the object belongs to.
     */
    public CharBuf*
    Get_Class_Name(Obj *self);

    /** Indicate whether the object is a descendent of <code>ancestor</code>.
     */
    public bool_t
    Is_A(Obj *self, VTable *ancestor);

    /** Generic stringification: "ClassName@hex_mem_address".
     */
    public incremented CharBuf*
    To_String(Obj *self);

    /** Convert the object to a 64-bit integer.
     */
    public abstract int64_t
    To_I64(Obj *self);

    /** Convert the object to a double precision floating point number.
     */
    public abstract double
    To_F64(Obj *self);

    /** Evaluate the object in a boolean context.  By default, invokes
     * To_I64() and returns true if it is non-zero.
     */
    public bool_t
    To_Bool(Obj *self);

    /** Serialize the object by writing to the supplied OutStream.
     */
    public void
    Serialize(Obj *self, OutStream *outstream);

    /** Inflate an object by reading the serialized form from the instream.
     * The assumption is that the object has been allocated, assigned a
     * refcount and a vtable, but that everything else is uninitialized.
     */
    public incremented Obj*
    Deserialize(decremented Obj *self, InStream *instream);

    /** Return a representation of the object using only scalars, hashes, and
     * arrays.  Some implementations support JSON serialization via Dump() and
     * its companion method, Load(); for others, Dump() is only a debugging
     * aid.  The default simply calls To_String().
     */
    public incremented Obj*
    Dump(Obj *self);

    /** Create an object from the output of a call to Dump().
     *
     * @param dump The output of Dump().
     */
    public abstract incremented Obj*
    Load(Obj *self, Obj *dump);

    /** Update the internal state of the object to mimic that of
     * <code>other</code>.
     */
    public abstract void
    Mimic(Obj *self, Obj *other);
}

__C__
static CHY_INLINE void
lucy_Obj_super_destroy(lucy_Obj *self, lucy_VTable *vtable) {
    Lucy_Obj_Destroy_t super_destroy
        = CFISH_SUPER_METHOD_PTR(vtable, Lucy_Obj_Destroy);
    super_destroy(self);
}

#define LUCY_SUPER_DESTROY(_self, _vtable) \
    lucy_Obj_super_destroy((lucy_Obj*)_self, _vtable)

static CHY_INLINE lucy_Obj*
lucy_Obj_incref(lucy_Obj *self) {
    if (self != NULL) { return Lucy_Obj_Inc_RefCount(self); }
    else { return NULL; }
}

#define CFISH_INCREF(_self) lucy_Obj_incref((lucy_Obj*)_self)

static CHY_INLINE uint32_t
lucy_Obj_decref(lucy_Obj *self) {
    if (self != NULL) { return Lucy_Obj_Dec_RefCount(self); }
    else { return 0; }
}

#define CFISH_DECREF(_self) lucy_Obj_decref((lucy_Obj*)_self)

#ifdef LUCY_USE_SHORT_NAMES
  #define SUPER_DESTROY(_self, _vtable)   LUCY_SUPER_DESTROY(_self, _vtable)
  #define INCREF(_self)                   CFISH_INCREF(_self)
  #define DECREF(_self)                   CFISH_DECREF(_self)
#endif

__END_C__