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[Go] Revert commit 5e88857 to undelete the 'callback' and 'extend' examples.

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The 'callback' and 'extend' examples were presumed to be obsoleted by the new
'director' example.  The examples are helpful though to have similar examples
across target languages and hence the commit @5e88857 which removed these
examples got reverted.
This commit is contained in:
Michael Schaller 2015-08-08 19:44:41 +02:00
commit a941e5b605
14 changed files with 374 additions and 1 deletions
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16
Examples/go/callback/Makefile Normal file
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TOP = ../..
SWIG = $(TOP)/../preinst-swig
CXXSRCS = callback.cxx
TARGET = example
INTERFACE = example.i
SWIGOPT =
check: build
$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' CXXSRCS='$(CXXSRCS)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go_run
build:
$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' CXXSRCS='$(CXXSRCS)' SWIG='$(SWIG)' \
SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go_cpp
clean:
$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' INTERFACE='$(INTERFACE)' go_clean

4
Examples/go/callback/callback.cxx Normal file
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/* File : example.cxx */
#include "example.h"

23
Examples/go/callback/example.h Normal file
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/* File : example.h */
#include <cstdio>
#include <iostream>
class Callback {
public:
virtual ~Callback() { std::cout << "Callback::~Callback()" << std:: endl; }
virtual void run() { std::cout << "Callback::run()" << std::endl; }
};
class Caller {
private:
Callback *_callback;
public:
Caller(): _callback(0) {}
~Caller() { delCallback(); }
void delCallback() { delete _callback; _callback = 0; }
void setCallback(Callback *cb) { delCallback(); _callback = cb; }
void call() { if (_callback) _callback->run(); }
};

11
Examples/go/callback/example.i Normal file
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/* File : example.i */
%module(directors="1") example
%{
#include "example.h"
%}
/* turn on director wrapping Callback */
%feature("director") Callback;
%include "example.h"

81
Examples/go/callback/index.html Normal file
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<html>
<head>
<title>SWIG:Examples:go:callback</title>
</head>
<body bgcolor="#ffffff">
<tt>SWIG/Examples/go/callback/</tt>
<hr>
<H2>Implementing C++ callbacks in Go</H2>
<p>
This example illustrates how to use directors to implement C++
callbacks in Go.
</p>
<p>
Because Go and C++ use inheritance differently, you must call a
different function to create a class which uses callbacks. Instead of
calling the usual constructor function whose name is <tt>New</tt>
followed by the capitalized name of the class, you call a function
named <tt>NewDirector</tt> followed by the capitalized name of the
class.
</p>
<p>
The first argument to the <tt>NewDirector</tt> function is an instance
of a type. The <tt>NewDirector</tt> function will return an interface
value as usual. However, when calling any method on the returned
value, the program will first check whether the value passed
to <tt>NewDirector</tt> implements that method. If it does, the
method will be called in Go. This is true whether the method is
called from Go code or C++ code.
</p>
<p>
Note that the Go code will be called with just the Go value, not the
C++ value. If the Go code needs to call a C++ method on itself, you
need to get a copy of the C++ object. This is typically done as
follows:
<blockquote>
<pre>
type Child struct { abi Parent }
func (p *Child) ChildMethod() {
p.abi.ParentMethod()
}
func f() {
p := &Child{nil}
d := NewDirectorParent(p)
p.abi = d
...
}
</pre>
</blockquote>
In other words, we first create the Go value. We pass that to
the <tt>NewDirector</tt> function to create the C++ value; this C++
value will be created with an association to the Go value. We then
store the C++ value in the Go value, giving us the reverse
association. That permits us to call parent methods from the child.
</p>
<p>
To delete a director object, use the function <tt>DeleteDirector</tt>
followed by the capitalized name of the class.
</p>
<p>
<ul>
<li><a href="example.h">example.h</a>. Header file containing some enums.
<li><a href="example.i">example.i</a>. Interface file.
<li><a href="runme.go">runme.go</a>. Sample Go program.
</ul>
<hr>
</body>
</html>

41
Examples/go/callback/runme.go Normal file
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package main
import (
. "./example"
"fmt"
)
func main() {
fmt.Println("Adding and calling a normal C++ callback")
fmt.Println("----------------------------------------")
caller := NewCaller()
callback := NewCallback()
caller.SetCallback(callback)
caller.Call()
caller.DelCallback()
callback = NewDirectorCallback(new(GoCallback))
fmt.Println()
fmt.Println("Adding and calling a Go callback")
fmt.Println("------------------------------------")
caller.SetCallback(callback)
caller.Call()
caller.DelCallback()
// Test that a double delete does not occur as the object has
// already been deleted from the C++ layer.
DeleteDirectorCallback(callback)
fmt.Println()
fmt.Println("Go exit")
}
type GoCallback struct{}
func (p *GoCallback) Run() {
fmt.Println("GoCallback.Run")
}

2
Examples/go/check.list
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@ -1,8 +1,10 @@
# see top-level Makefile.in
callback
class
constants
director
enum
extend
funcptr
multimap
pointer

16
Examples/go/extend/Makefile Normal file
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@ -0,0 +1,16 @@
TOP = ../..
SWIG = $(TOP)/../preinst-swig
CXXSRCS = extend.cxx
TARGET = example
INTERFACE = example.i
SWIGOPT =
check: build
$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' CXXSRCS='$(CXXSRCS)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go_run
build:
$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' CXXSRCS='$(CXXSRCS)' SWIG='$(SWIG)' \
SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go_cpp
clean:
$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' INTERFACE='$(INTERFACE)' go_clean

56
Examples/go/extend/example.h Normal file
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/* File : example.h */
#include <cstdio>
#include <iostream>
#include <vector>
#include <string>
#include <cmath>
class Employee {
private:
std::string name;
public:
Employee(const char* n): name(n) {}
virtual std::string getTitle() { return getPosition() + " " + getName(); }
virtual std::string getName() { return name; }
virtual std::string getPosition() const { return "Employee"; }
virtual ~Employee() { printf("~Employee() @ %p\n", (void *)this); }
};
class Manager: public Employee {
public:
Manager(const char* n): Employee(n) {}
virtual std::string getPosition() const { return "Manager"; }
};
class EmployeeList {
std::vector<Employee*> list;
public:
EmployeeList() {
list.push_back(new Employee("Bob"));
list.push_back(new Employee("Jane"));
list.push_back(new Manager("Ted"));
}
void addEmployee(Employee *p) {
list.push_back(p);
std::cout << "New employee added. Current employees are:" << std::endl;
std::vector<Employee*>::iterator i;
for (i=list.begin(); i!=list.end(); i++) {
std::cout << " " << (*i)->getTitle() << std::endl;
}
}
const Employee *get_item(int i) {
return list[i];
}
~EmployeeList() {
std::vector<Employee*>::iterator i;
std::cout << "~EmployeeList, deleting " << list.size() << " employees." << std::endl;
for (i=list.begin(); i!=list.end(); i++) {
delete *i;
}
std::cout << "~EmployeeList empty." << std::endl;
}
};

15
Examples/go/extend/example.i Normal file
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/* File : example.i */
%module(directors="1") example
%{
#include "example.h"
%}
%include "std_vector.i"
%include "std_string.i"
/* turn on director wrapping for Manager */
%feature("director") Employee;
%feature("director") Manager;
%include "example.h"

4
Examples/go/extend/extend.cxx Normal file
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/* File : example.cxx */
#include "example.h"

27
Examples/go/extend/index.html Normal file
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<html>
<head>
<title>SWIG:Examples:go:extend</title>
</head>
<body bgcolor="#ffffff">
<tt>SWIG/Examples/go/extend/</tt>
<hr>
<H2>Extending a simple C++ class in Go</H2>
<p>
This example illustrates the extending of a C++ class with cross
language polymorphism.
<p>
<ul>
<li><a href="example.h">example.h</a>. Header file containing some enums.
<li><a href="example.i">example.i</a>. Interface file.
<li><a href="runme.go">runme.go</a>. Sample Go program.
</ul>
<hr>
</body>
</html>

76
Examples/go/extend/runme.go Normal file
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// This file illustrates the cross language polymorphism using directors.
package main
import (
. "./example"
"fmt"
)
type CEO struct{}
func (p *CEO) GetPosition() string {
return "CEO"
}
func main() {
// Create an instance of CEO, a class derived from the Go
// proxy of the underlying C++ class. The calls to getName()
// and getPosition() are standard, the call to getTitle() uses
// the director wrappers to call CEO.getPosition().
e := NewDirectorManager(new(CEO), "Alice")
fmt.Println(e.GetName(), " is a ", e.GetPosition())
fmt.Println("Just call her \"", e.GetTitle(), "\"")
fmt.Println("----------------------")
// Create a new EmployeeList instance. This class does not
// have a C++ director wrapper, but can be used freely with
// other classes that do.
list := NewEmployeeList()
// EmployeeList owns its items, so we must surrender ownership
// of objects we add.
// e.DisownMemory()
list.AddEmployee(e)
fmt.Println("----------------------")
// Now we access the first four items in list (three are C++
// objects that EmployeeList's constructor adds, the last is
// our CEO). The virtual methods of all these instances are
// treated the same. For items 0, 1, and 2, all methods
// resolve in C++. For item 3, our CEO, GetTitle calls
// GetPosition which resolves in Go. The call to GetPosition
// is slightly different, however, because of the overridden
// GetPosition() call, since now the object reference has been
// "laundered" by passing through EmployeeList as an
// Employee*. Previously, Go resolved the call immediately in
// CEO, but now Go thinks the object is an instance of class
// Employee. So the call passes through the Employee proxy
// class and on to the C wrappers and C++ director, eventually
// ending up back at the Java CEO implementation of
// getPosition(). The call to GetTitle() for item 3 runs the
// C++ Employee::getTitle() method, which in turn calls
// GetPosition(). This virtual method call passes down
// through the C++ director class to the Java implementation
// in CEO. All this routing takes place transparently.
fmt.Println("(position, title) for items 0-3:")
fmt.Println(" ", list.Get_item(0).GetPosition(), ", \"", list.Get_item(0).GetTitle(), "\"")
fmt.Println(" ", list.Get_item(1).GetPosition(), ", \"", list.Get_item(1).GetTitle(), "\"")
fmt.Println(" ", list.Get_item(2).GetPosition(), ", \"", list.Get_item(2).GetTitle(), "\"")
fmt.Println(" ", list.Get_item(3).GetPosition(), ", \"", list.Get_item(3).GetTitle(), "\"")
fmt.Println("----------------------")
// Time to delete the EmployeeList, which will delete all the
// Employee* items it contains. The last item is our CEO,
// which gets destroyed as well.
DeleteEmployeeList(list)
fmt.Println("----------------------")
// All done.
fmt.Println("Go exit")
}

3
Examples/go/index.html
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@ -21,7 +21,8 @@ certain C declarations are turned into constants.
<li><a href="pointer/index.html">pointer</a>. Simple pointer handling.
<li><a href="funcptr/index.html">funcptr</a>. Pointers to functions.
<li><a href="template/index.html">template</a>. C++ templates.
<li><a href="director/index.html">director</a>. Example how to utilize the director feature.
<li><a href="callback/index.html">callback</a>. C++ callbacks using directors.
<li><a href="extend/index.html">extend</a>. Polymorphism using directors.
</ul>
<h2>Compilation Issues</h2>