dsfml.system.err source code

1 /*
2  * DSFML - The Simple and Fast Multimedia Library for D
3  *
4  * Copyright (c) 2013 - 2018 Jeremy DeHaan (dehaan.jeremiah@gmail.com)
5  *
6  * This software is provided 'as-is', without any express or implied warranty.
7  * In no event will the authors be held liable for any damages arising from the
8  * use of this software.
9  *
10  * Permission is granted to anyone to use this software for any purpose,
11  * including commercial applications, and to alter it and redistribute it
12  * freely, subject to the following restrictions:
13  *
14  * 1. The origin of this software must not be misrepresented; you must not claim
15  * that you wrote the original software. If you use this software in a product,
16  * an acknowledgment in the product documentation would be appreciated but is
17  * not required.
18  *
19  * 2. Altered source versions must be plainly marked as such, and must not be
20  * misrepresented as being the original software.
21  *
22  * 3. This notice may not be removed or altered from any source distribution
23  *
24  *
25  * DSFML is based on SFML (Copyright Laurent Gomila)
26  */
27 
28 /**
29  * By default, $(U err) outputs to the same location as `stderr`, which is the
30  * console if there's one available.
31  *
32  * It is a standard std.stdio.File instance, so it supports all the functions as
33  * defined by this structure (write, writeln, open, lock, etc.)
34  *
35  * $(U err) can be redirected to write to another output, independantly of
36  * `stderr`, by using the `open` function. Note that unlike SFML's `err()`,
37  * DSFML's `err` cannot be redirected to 'nothing' at this time.
38  *
39  * Example:
40  * ---
41  * // Redirect to a file
42  * auto file = File("dsfml-log.txt", "w");
43  * auto previous = err;
44  * err = file;
45  *
46  * // Restore the original output
47  * err = previous;
48  * ---
49  */
50 module dsfml.system.err;
51 
52 import std.stdio;
53 
54 /**
55 * Standard std.stdio.File instance used by DSFML to output warnings and errors.
56 */
57 File err;
58 
59 static this()
60 {
61 	//Let's our err output go to the console by default
62 	err = stderr;
63 
64 	//redirect sf:err()
65 	sfErr_redirect(&writeToErr);
66 }
67 
68 //Redirect sf::err() to write to our err File instance
69 private extern(C) void sfErr_redirect(void function(const(char*) str, int size) writeFunc);
70 
71 //export a function to be used in C++ so that SFML can write to err
72 private extern(C) void writeToErr(const(char*) str, int size)
73 {
74 	err.write(str[0..size]);
75 }
76 
77 unittest
78 {
79 	version(DSFML_Unittest_System)
80 	{
81 		import std.stdio;
82 		import std.file;
83 		import dsfml.graphics.texture;
84 
85 		writeln("Unit test for err");
86 
87 		writeln("Writing a line to err");
88 		err.writeln("This line was written with err.");
89 
90 		writeln("Routing err to a file, and then writing to it.");
91 		err.open("log.txt", "w");
92 
93 		err.writeln("This line was written with err after being routed to log.txt");
94 
95 		auto noTexture = new Texture();
96 
97 		//This should generate a message from SFML that get's written to out output file
98 		noTexture.loadFromFile("nonexistantTexture1.png");
99 		noTexture.loadFromFile("nonexistantTexture2.png");
100 
101 
102 		err.detach();//need to detach before being able to read the contents of the file(it's in use while open)
103 
104 		writeln("Reading log.txt to confirm its contents.");
105 
106 		auto contents = cast(string)read("log.txt");
107 
108 		writeln("The contents of the text file are as follows: ", contents);
109 
110 		writeln("Routing err back to the console.");
111 		err = stderr;//in this case, stderr is still writing to the console, but I could have used stdout as well.
112 
113 		writeln("And writing to err one final time.");
114 		err.writeln("This is the last line in the unit test to be written to err!");
115 
116 		writeln();
117 	}
118 
119 }