[Go] Documentation cleanup of obsolete 'callback' and 'extend' examples.
After commit 17b1c1c (pull request 447; issue 418) the 'callback' and 'extend'
examples have been removed in favor of the 'director' example.
This commit is contained in:
Michael Schaller
parent
17b1c1c2d3
commit
736613e26c
14 changed files with 3 additions and 376 deletions
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@ -1,16 +0,0 @@
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TOP = ../..
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SWIG = $(TOP)/../preinst-swig
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CXXSRCS = callback.cxx
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TARGET = example
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INTERFACE = example.i
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SWIGOPT =
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check: build
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$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' CXXSRCS='$(CXXSRCS)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go_run
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build:
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$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' CXXSRCS='$(CXXSRCS)' SWIG='$(SWIG)' \
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SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go_cpp
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clean:
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$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' INTERFACE='$(INTERFACE)' go_clean
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@ -1,4 +0,0 @@
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/* File : example.cxx */
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#include "example.h"
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@ -1,23 +0,0 @@
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/* File : example.h */
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#include <cstdio>
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#include <iostream>
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class Callback {
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public:
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virtual ~Callback() { std::cout << "Callback::~Callback()" << std:: endl; }
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virtual void run() { std::cout << "Callback::run()" << std::endl; }
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};
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class Caller {
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private:
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Callback *_callback;
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public:
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Caller(): _callback(0) {}
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~Caller() { delCallback(); }
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void delCallback() { delete _callback; _callback = 0; }
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void setCallback(Callback *cb) { delCallback(); _callback = cb; }
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void call() { if (_callback) _callback->run(); }
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};
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@ -1,11 +0,0 @@
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/* File : example.i */
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%module(directors="1") example
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%{
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#include "example.h"
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%}
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/* turn on director wrapping Callback */
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%feature("director") Callback;
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%include "example.h"
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@ -1,81 +0,0 @@
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<html>
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<head>
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<title>SWIG:Examples:go:callback</title>
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</head>
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<body bgcolor="#ffffff">
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<tt>SWIG/Examples/go/callback/</tt>
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<hr>
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<H2>Implementing C++ callbacks in Go</H2>
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<p>
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This example illustrates how to use directors to implement C++
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callbacks in Go.
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</p>
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<p>
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Because Go and C++ use inheritance differently, you must call a
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different function to create a class which uses callbacks. Instead of
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calling the usual constructor function whose name is <tt>New</tt>
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followed by the capitalized name of the class, you call a function
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named <tt>NewDirector</tt> followed by the capitalized name of the
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class.
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</p>
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<p>
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The first argument to the <tt>NewDirector</tt> function is an instance
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of a type. The <tt>NewDirector</tt> function will return an interface
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value as usual. However, when calling any method on the returned
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value, the program will first check whether the value passed
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to <tt>NewDirector</tt> implements that method. If it does, the
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method will be called in Go. This is true whether the method is
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called from Go code or C++ code.
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</p>
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<p>
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Note that the Go code will be called with just the Go value, not the
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C++ value. If the Go code needs to call a C++ method on itself, you
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need to get a copy of the C++ object. This is typically done as
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follows:
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<blockquote>
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<pre>
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type Child struct { abi Parent }
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func (p *Child) ChildMethod() {
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p.abi.ParentMethod()
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}
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func f() {
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p := &Child{nil}
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d := NewDirectorParent(p)
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p.abi = d
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...
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}
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</pre>
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</blockquote>
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In other words, we first create the Go value. We pass that to
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the <tt>NewDirector</tt> function to create the C++ value; this C++
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value will be created with an association to the Go value. We then
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store the C++ value in the Go value, giving us the reverse
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association. That permits us to call parent methods from the child.
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</p>
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<p>
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To delete a director object, use the function <tt>DeleteDirector</tt>
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followed by the capitalized name of the class.
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</p>
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<p>
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<ul>
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<li><a href="example.h">example.h</a>. Header file containing some enums.
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<li><a href="example.i">example.i</a>. Interface file.
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<li><a href="runme.go">runme.go</a>. Sample Go program.
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</ul>
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<hr>
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</body>
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</html>
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@ -1,41 +0,0 @@
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package main
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import (
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. "./example"
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"fmt"
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)
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func main() {
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fmt.Println("Adding and calling a normal C++ callback")
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fmt.Println("----------------------------------------")
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caller := NewCaller()
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callback := NewCallback()
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caller.SetCallback(callback)
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caller.Call()
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caller.DelCallback()
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callback = NewDirectorCallback(new(GoCallback))
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fmt.Println()
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fmt.Println("Adding and calling a Go callback")
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fmt.Println("------------------------------------")
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caller.SetCallback(callback)
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caller.Call()
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caller.DelCallback()
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// Test that a double delete does not occur as the object has
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// already been deleted from the C++ layer.
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DeleteDirectorCallback(callback)
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fmt.Println()
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fmt.Println("Go exit")
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}
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type GoCallback struct{}
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func (p *GoCallback) Run() {
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fmt.Println("GoCallback.Run")
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}
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