File: README.CodingStyle.md

package info (click to toggle)
subtitlecomposer 0.6.4-2
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 5,920 kB
  • ctags: 3,521
  • sloc: cpp: 29,965; xml: 83; sh: 58; python: 53; ruby: 42; makefile: 24
file content (428 lines) | stat: -rw-r--r-- 8,151 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
## SubtitleComposer Coding Style ##

### Indentation

1 tab is used for indentation

Tab, not spaces!


### Declaring variables

Declare each variable on a separate line

Avoid short or meaningless names (e.g. "a", "rbarr", "nughdeget")

Single character variable names are only okay for counters and temporaries, where the purpose of the variable is obvious

Wait when declaring a variable until it is needed

```C++
	// Wrong
	int a, b;
	char *c, *d;

	// Correct
	int height;
	int width;
	char *nameOfThis;
	char *nameOfThat;
```

Variables and functions start with a lower-case letter. Each consecutive word in a variable’s name starts with an upper-case letter

Avoid abbreviations

```C++
	// Wrong
	short Cntr;
	char ITEM_DELIM = '\t';

	// Correct
	short counter;
	char itemDelimiter = '\t';
```

Classes always start with an upper-case letter. Public classes start with a ‘Q’ (QRgb) followed by an upper case letter. Public functions most often start with a ‘q’ (qRgb).
Acronyms are camel-cased (e.g. QXmlStreamReader, not QXMLStreamReader).


### Whitespace

Use blank lines to group statements together where suited
Always use only one blank line
Do not use space after a keyword
Always use one single space before a curly brace:

```C++
	// Wrong
	if (foo){
	}

	// Correct
	if(foo) {
	}
```

For pointers or references, always use a single space between the type and ‘*’ or ‘&’, but no space between the ‘*’ or ‘&’ and the variable name:

```C++
	// Correct
	char *x;
	const QString &myString;
	const char * const y = "hello";
```

Surround binary operators with spaces
No space after a cast
Avoid C-style casts when possible

```C++
	// Wrong
	char* blockOfMemory = (char*)malloc(data.size());

	// Correct
	char *blockOfMemory = reinterpret_cast<char *>(malloc(data.size()));
```

Do not put multiple statements on one line
By extension, use a new line for the body of a control flow statement:

```C++
	// Wrong
	if(foo) bar();

	// Correct
	if(foo)
		bar();
```


### Braces

Use attached braces: The opening brace goes on the same line as the start of the statement. If the closing brace is followed by another keyword, it goes into the same line as well:

```C++
	// Wrong
	if(codec)
	{
	}
	else
	{
	}

	// Correct
	if(codec) {
	} else {
	}
```

Exception: Function implementations and class declarations always have the left brace on the start of a line:

```C++
	// Correct
	static void
	foo(int g)
	{
		qDebug("foo: %i", g);
	}

	class Moo
	{
	};
```

Use curly braces only when the body of a conditional statement contains more than one line:

```C++
	// Wrong
	if(address.isEmpty()) {
		return false;
	}

	for(int i = 0; i < 10; ++i) {
		qDebug("%i", i);
	}

	// Correct
	if(address.isEmpty())
		return false;

	for(int i = 0; i < 10; ++i)
		qDebug("%i", i);
```

Exception 1: Use braces also if the parent statement covers several lines / wraps:

```C++
	// Correct
	if(address.isEmpty() || !isValid()
		|| !codec) {
		return false;
	}
```

Exception 2: Brace symmetry: Use braces also in if-then-else blocks where either the if-code or the else-code covers several lines:

```C++
	// Wrong
	if(address.isEmpty())
		return false;
	else {
		qDebug("%s", qPrintable(address));
		++it;
	}

	// Correct
	if(address.isEmpty()) {
		return false;
	} else {
		qDebug("%s", qPrintable(address));
		++it;
	}

	// Wrong
	if(a)
		if(b)
			...
		else
			...
	// Correct
	if(a) {
		if(b)
			...
		else
			...
	}
```

Use curly braces when the body of a conditional statement is empty

```C++
	// Wrong
	while(a);

	// Correct
	while(a) {}
```


### Parentheses

Use parentheses to group expressions:

```C++
	// Wrong
	if(a && b || c)

	// Correct
	if((a && b) || c)

	// Wrong
	a + b & c

	// Correct
	(a + b) & c
```


### Switch statements

The case labels are in the same column as the switch
Every case must have a break (or return) statement at the end or a comment to indicate that there’s intentionally no break, unless another case follows immediately.

```C++
	// Correct
	switch(myEnum) {
	case Value1:
		doSomething();
		break;
	case Value2:
	case Value3:
		doSomethingElse();
		// fall through
	default:
		defaultHandling();
		break;
	}
```

Jump statements (break, continue, return, and goto)

Do not put ‘else’ after jump statements:

```C++
	// Wrong
	if(thisOrThat)
		return;
	else
		somethingElse();

	// Correct
	if(thisOrThat)
		return;
	somethingElse();
```

Exception: If the code is inherently symmetrical, use of ‘else’ is allowed to visualize that symmetry


### Line breaks

Keep lines shorter than 100 characters; wrap if necessary
Commas go at the end of wrapped lines; operators start at the beginning of the new lines. An operator at the end of the line is easy to miss if the editor is too narrow.

```C++
	// Wrong
	if(longExpression +
		otherLongExpression +
		otherOtherLongExpression) {
	}

	// Correct
	if(longExpression
		+ otherLongExpression
		+ otherOtherLongExpression) {
	}
```


### Inheritance and the `virtual` keyword

When reimplementing a virtual method, do not put the `virtual` keyword in the header file.
On Qt5, annotate them with the [Q_DECL_OVERRIDE](http://qt-project.org/doc/qt-5.0/qtcore/qtglobal.html#Q_DECL_OVERRIDE) macro after the function declaration, just before the ‘;’ (or the ‘{’ ).


### Qt Includes

Do not use both the module and class name for Qt includes.

```C++
	// Correct
	#include <QString>

	// Wrong
	#include <QtCore/QString>
```


### C++11 Lambdas

You can use lambdas with the following restrictions:

* You have to explicitly specify the return type (unless it's void), if the lambda contains more than a single expression.

```C++
	// Correct
	[]() -> QString {
		Foo *foo = activeFoo();
		return foo ? foo->displayName() : QString();
	});

	// Wrong
	[]() {
		Foo *foo = activeFoo();
		return foo ? foo->displayName() : QString();
	});
```

* If you use static functions from the class that the lambda is located in, you have to explicitly capture this. Otherwise it does not compile with g++ 4.7 and earlier.
```C++
	// Correct
	void
	Foo::something()
	{
		...
		[this]() { Foo::someStaticFunction(); }
		...
	}

	// Wrong
	void
	Foo::something()
	{
		...
		[]() { Foo::someStaticFunction(); }
		...
	}
```

Format the lambda according to the following rules:

* Always write parentheses for the parameter list, even if the function does not take parameters.

```C++
	// Correct
	[]() { doSomething(); }

	// Wrong
	[] { doSomething(); }
```

* Place the capture-list, parameter list, return type, and opening brace on the first line, the body indented on the following lines, and the closing brace on a new line.
```C++
	// Correct
	[]() -> bool {
		something();
		return isSomethingElse();
	}

	// Wrong
	[]() -> bool { something();
		somethingElse(); }
```

* Place a closing parenthesis and semicolon of an enclosing function call on the same line as the closing brace of the lambda.
```C++
	// Correct
	foo([]() {
		something();
	});
```

* If you are using a lambda in an 'if' statement, start the lambda on a new line, to avoid confusion between the opening brace for the lambda and the opening brace for the 'if' statement.
```C++
	// Correct
	if(anyOf(fooList,
		[](Foo foo) {
			return foo.isGreat();
		}) {
		return;
	}

	// Correct - place the lambda completely on one line if it fits
	if(foo([]() { return true; })) {
		...
	}

	// Wrong
	if(anyOf(fooList, [](Foo foo) {
			return foo.isGreat();
		}) {
		return;
	}
```


### C++11 auto keyword

You can use the auto keyword in the following cases. If in doubt (e.g. using auto could make the code less readable) do not use auto. Keep in mind that code is read much more often than written.

* When it avoids repetition of a type in the same statement.
```C++
	// Correct
	auto something = new MyCustomType;
	auto keyEvent = static_cast<QKeyEvent *>(event);
	auto myList = QStringList() << QLatin1String("FooThing") << QLatin1String("BarThing");
```

* When assigning iterator types.
```C++
	// Correct
	auto it = myList.const_iterator();
```


### General exception

When strictly following a rule makes your code look bad, feel free to break it