Enlightenment CVS committal
Author : mej
Project : eterm
Module : libast
Dir : eterm/libast/src
Modified Files:
obj.c
Log Message:
Fri Nov 21 18:40:52 2003 Michael Jennings (mej)
Added more docs to obj.c. I need to go back and be more verbose on
some things, though.
These can be viewed online at http://www.eterm.org/libast/ for those
who'd like to get a sneak peak at them. Please report any obvious
errors, typos, etc. Those with developer access, feel free to
contribute or correct any errors or inconsistencies you find.
===================================================================
RCS file: /cvsroot/enlightenment/eterm/libast/src/obj.c,v
retrieving revision 1.17
retrieving revision 1.18
diff -u -3 -r1.17 -r1.18
--- obj.c 19 Nov 2003 04:21:15 -0000 1.17
+++ obj.c 21 Nov 2003 23:43:26 -0000 1.18
@@ -28,11 +28,11 @@
* This file contains the basic object class.
*
* @author Michael Jennings <[EMAIL PROTECTED]>
- * $Revision: 1.17 $
- * $Date: 2003/11/19 04:21:15 $
+ * $Revision: 1.18 $
+ * $Date: 2003/11/21 23:43:26 $
*/
-static const char cvs_ident[] = "$Id: obj.c,v 1.17 2003/11/19 04:21:15 mej Exp $";
+static const char cvs_ident[] = "$Id: obj.c,v 1.18 2003/11/21 23:43:26 mej Exp $";
#ifdef HAVE_CONFIG_H
# include <config.h>
@@ -41,7 +41,23 @@
#include <libast_internal.h>
/* *INDENT-OFF* */
-/* The actual class structure for the "obj" type. */
+/**
+ * The actual class structure for the @c obj type.
+ *
+ * This structure is the actual class for the @c obj type. All LibAST
+ * objects contain a spif_class_t member called @c cls which points to
+ * a class structure, like this one. The first structure member is a
+ * pointer to the class name. Each class uses the same pointer, so
+ * you can compare the pointer values rather than having to compare
+ * strings. All other members are function pointers which reference
+ * the object-agnostic routines that object supports. ALL LibAST
+ * objects support at least 8 operations: new, init, done, del, show,
+ * comp, dup, and type. Other classes may define other standard
+ * functions. (This is used for doing interface classes.)
+ *
+ * @see DOXGRP_OBJ
+ * @ingroup DOXGRP_OBJ
+ */
static SPIF_CONST_TYPE(class) o_class = {
SPIF_DECL_CLASSNAME(obj),
(spif_func_t) spif_obj_new,
@@ -54,10 +70,15 @@
(spif_func_t) spif_obj_type
};
-/*
- * The class instance for the "obj" type...a pointer to the struct
- * above. This pointer value is the very first thing stored in each
- * instance of an "obj."
+/**
+ * The class instance for the @c obj type.
+ *
+ * This defines the spif_class_t for the @c obj type so that it points
+ * to the spif_const_class_t structure above. This pointer value is
+ * the very first thing stored in each * instance of an "obj."
+ *
+ * @see DOXGRP_OBJ
+ * @ingroup DOXGRP_OBJ
*/
SPIF_TYPE(class) SPIF_CLASS_VAR(obj) = &o_class;
/* *INDENT-ON* */
@@ -130,6 +151,16 @@
* This function initializes the member variables of the @c obj
* instance to their appropriate "bootstrap" values.
*
+ * @note Though the calling of the parent's initializer is customary
+ * and proper in derived classes, for subtypes of @c obj, this is not
+ * strictly necessary. All this function does is set the class to
+ * that of an @c obj, which the child must undo anyway (by calling
+ * <tt>spif_obj_set_class(self, SPIF_CLASS_VAR(XXX))</tt>, where
+ * <tt>XXX</tt> is the class name, like below). Thus, it is
+ * acceptable for direct decendents of @c obj to not call this
+ * function. However, anything whose parent type is @a not @c obj
+ * MUST call their parent's init function.
+ *
* @param self The @c obj instance to be initialized.
* @return #TRUE if successful, #FALSE otherwise.
*
@@ -162,22 +193,44 @@
return TRUE;
}
-spif_class_t
-spif_obj_get_class(spif_obj_t self)
-{
- return ((self) ? (self->cls) : SPIF_NULL_TYPE(class));
-}
-
-spif_bool_t
-spif_obj_set_class(spif_obj_t self, spif_class_t cls)
-{
- if (SPIF_OBJ_ISNULL(self)) {
- return FALSE;
- }
- SPIF_OBJ_CLASS(self) = cls;
- return TRUE;
-}
-
+/**
+ * Show an object and its contents.
+ *
+ * This function, as it is written here, doesn't do a whole hell of a
+ * lot. But this standard member function (i.e., all objects must
+ * have one) provides the mechanism for which an object can display
+ * not only itself and its particular values, but those of any parent
+ * class or member object. Besides the object to be displayed, this
+ * function is passed the variable name for that object (usually a
+ * constant string, like "foo"), a @c str object, possibly NULL, to be
+ * added to and returned, and an indent level, possibly 0, to
+ * represent how many leading spaces should pad the resulting output.
+ * The @c str object returned is either @a buff, or a new @c str if @a
+ * buff was passed as NULL. Appended to it will be the description of
+ * the object followed by a newline. This description may include
+ * descriptions of any number of child variables, parent objects, etc.
+ *
+ * Implementing this function properly is key to simplifying the
+ * examination of objects through the use of debugging code. I @b
+ * highly recommend looking at some examples of how this function
+ * should be implemented.
+ *
+ * The simplest way to display an object is to use the SPIF_SHOW()
+ * macro. This macro takes the object (@a self) and a file descriptor
+ * (like @c stderr or #LIBAST_DEBUG_FD), calls the object's @c show
+ * method, and prints the resulting string on the given file
+ * descriptor, freeing it afterward. No muss, no fuss.
+ *
+ * @param self The @c obj instance.
+ * @param name The name of the variable passed as @a self.
+ * @param buff A @c str object, possibly NULL, used as the buffer.
+ * @param indent The number of spaces with which to pad the line.
+ * @return The @c str object, or a new one if @a buff was NULL,
+ * describing @a self.
+ *
+ * @see DOXGRP_OBJ, SPIF_SHOW()
+ * @ingroup DOXGRP_OBJ
+ */
spif_str_t
spif_obj_show(spif_obj_t self, spif_charptr_t name, spif_str_t buff, size_t indent)
{
@@ -198,12 +251,51 @@
return buff;
}
+/**
+ * Compare two objects.
+ *
+ * As with most of the other member functions of the @c obj class,
+ * this one is really just a placeholder. The @c comp standard member
+ * function is used to compare two objects of a given type. The
+ * comparison can be implemented in any way, so long as it returns a
+ * consistent spif_cmp_t value. The simplest way is to compare the
+ * two object variables, as shown below, but often a more sensible
+ * method is warranted.
+ *
+ * @param self The first @c obj instance.
+ * @param other The second @c obj instance.
+ * @return A spif_cmp_t value representing the comparison of @a
+ * self and @a other.
+ *
+ * @see DOXGRP_OBJ, spif_str_comp(), spif_cmp_t, SPIF_CMP_FROM_INT()
+ * @ingroup DOXGRP_OBJ
+ */
spif_cmp_t
spif_obj_comp(spif_obj_t self, spif_obj_t other)
{
return (self == other);
}
+/**
+ * Duplicate an @c obj and its resources.
+ *
+ * The @c dup standard member function is responsible for returning a
+ * new object instance which contains the exact same value as the
+ * instance supplied to it. That means that any values are copied
+ * from the original to the duplicate, and any references (pointers
+ * and objects) are duplicated in the new instance, using MALLOC(),
+ * the member object's @c dup function, etc. The object returned MUST
+ * be independent of the original; i.e., calling @c done or @c del on
+ * the duplicate MUST NOT destroy or affect the original, or any of
+ * its data, in any way.
+ *
+ * @param self The @c obj instance.
+ * @return An exact duplicate of @a self which is identical to,
+ * but programmatically independent of, the original.
+ *
+ * @see DOXGRP_OBJ, spif_str_dup()
+ * @ingroup DOXGRP_OBJ
+ */
spif_obj_t
spif_obj_dup(spif_obj_t self)
{
@@ -214,10 +306,81 @@
return tmp;
}
+/**
+ * Obtain the class name of an @c obj.
+ *
+ * The @c type standard member function is responsible for returning
+ * the class name (as a spif_classname_t) of the supplied object. You
+ * will almost certainly want to implement it exactly as seen here.
+ * If you don't, know why.
+ *
+ * @param self The @c obj instance.
+ * @return The class name of @a self.
+ *
+ * @see DOXGRP_OBJ
+ * @ingroup DOXGRP_OBJ
+ */
spif_classname_t
spif_obj_type(spif_obj_t self)
{
return SPIF_OBJ_CLASSNAME(self);
+}
+
+/**
+ * Return the class of an object.
+ *
+ * This function returns the class (i.e., spif_class_t) of the
+ * supplied @c obj instance. Thanks to the Magic and Mystery of
+ * typecasting, any LibAST object can be passed to this function to
+ * obtain its class information, like so:
+ * <tt>spif_obj_get_class(SPIF_OBJ(foo))</tt> Or, simply use the
+ * SPIF_OBJ_CLASS() macro.
+ *
+ * Keep in mind that this will return the @a entire class. If you
+ * simply want the class name string, use SPIF_OBJ_CLASSNAME()
+ * instead.
+ *
+ * @param self The @c obj instance.
+ * @return The object's class, or NULL if @a self is NULL.
+ *
+ * @see DOXGRP_OBJ
+ * @ingroup DOXGRP_OBJ
+ */
+spif_class_t
+spif_obj_get_class(spif_obj_t self)
+{
+ return ((self) ? SPIF_OBJ_CLASS(self) : SPIF_NULL_TYPE(class));
+}
+
+/**
+ * Set an object's class.
+ *
+ * This function sets the class (i.e., spif_class_t) of the supplied
+ * @c obj instance. Thanks to the Magic and Mystery of typecasting,
+ * any LibAST object can be passed to this function to set its class
+ * information, like so: <tt>spif_obj_set_class(SPIF_OBJ(foo),
+ * SPIF_CLASS_VAR(XXX))</tt>, where <tt>XXX</tt> is the actual type of
+ * the object (like @c str or @c regexp). Any call to the @c init
+ * member of a parent class MUST be immediately followed by a call to
+ * this function like the one above. Failure to do so results in
+ * inaccurate class typing information, which kinda defeats the whole
+ * point, ya know?
+ *
+ * @param self The @c obj instance.
+ * @param cls The @c class for the given instance.
+ * @return #TRUE if successful, #FALSE otherwise.
+ *
+ * @see DOXGRP_OBJ
+ * @ingroup DOXGRP_OBJ
+ */
+spif_bool_t
+spif_obj_set_class(spif_obj_t self, spif_class_t cls)
+{
+ if (SPIF_OBJ_ISNULL(self)) {
+ return FALSE;
+ }
+ SPIF_OBJ_CLASS(self) = cls;
+ return TRUE;
}
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