RemoveBraces::optimizeStructure() - Code Metrics - Inspection of "Reorganized code" - s9e/SourceOptimizer - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( e86a78...1a9ef7 )

by Josh

created 2018-06-11 00:57 UTC

RemoveBraces::optimizeStructure() B

↳ Parent: RemoveBraces

Complexity

Conditions	5
Paths	6

Size

Total Lines	18
Code Lines	8

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	9
CRAP Score	5

Importance

Changes

Metric	Value
dl	0
loc	18
ccs	9
cts	9
cp	1
rs	8.8571
c	0
b	0
f	0
cc	5
eloc	8
nc	6
nop	1
crap	5

<?php

/**
* @package   s9e\SourceOptimizer
* @copyright Copyright (c) 2014-2018 The s9e Authors
* @license   http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\SourceOptimizer\Passes;

/**
* Optimizes the control structures of a script.
*
* Removes braces in control structures wherever possible. Prevents the generation of EXT_STMT
* opcodes where they're not strictly required.
*/
class RemoveBraces extends AbstractPass
{
	/**
	* @var array Offsets of braces that need to be preserved (offsets used as keys)
	*/
	protected $preservedBraces;

	/**
	* {@inheritdoc}
	*/
	public function optimizeStream()
	{
		$this->preservedBraces = [];
		$structures = [];
		while ($this->stream->valid())
		{
			if ($this->isControlStructure())
			{
				$structure = $this->parseControlStructure();
				if ($structure)
				{
					$structures[] = $structure;
				}
			}
			$this->stream->next();
		}

		$this->optimizeStructures($structures);
	}

	/**
	* Test whether the given structure's braces can be removed
	*
	* @param  array $structure
	* @return bool
	*/
	protected function canRemoveBracesFrom(array $structure)
	{
		return ($structure['statements'] <= 1 && !isset($this->preservedBraces[$structure['offsetRightBrace']]));
	}

	/**
	* Test whether the token at current offset is a control structure
	*
	* NOTE: we ignore T_DO since the braces are not optional
	*
	* @return bool
	*/
	protected function isControlStructure()
	{
		return $this->stream->isAny([T_ELSE, T_ELSEIF, T_FOR, T_FOREACH, T_IF, T_WHILE]);
	}

	/**
	* Test whether the token at current offset is an open curly brace
	*
	* @return bool
	*/
	protected function isCurlyOpen()
	{
		return ($this->stream->current() === '{' || $this->stream->isAny([T_CURLY_OPEN, T_DOLLAR_OPEN_CURLY_BRACES]));
	}

	/**
	* Test whether current token is followed by a function or class-related declaration
	*
	* @return bool
	*/
	protected function isFollowedByDeclaraction()
	{
		$keywords = [T_ABSTRACT, T_CLASS, T_FINAL, T_FUNCTION, T_INTERFACE, T_TRAIT];

		$offset = $this->stream->key();
		$this->stream->next();
		$this->stream->skipNoise();
		$isFollowedByFunction = ($this->stream->valid() && $this->stream->isAny($keywords));
		$this->stream->seek($offset);

		return $isFollowedByFunction;
	}

	/**
	* Optimize given T_ELSE structure
	*
	* @param  array $structure
	* @return void
	*/
	protected function optimizeElse(array $structure)
	{
		$this->stream->seek($structure['offsetLeftBrace']);
		$this->stream->next();
		$this->stream->skipNoise();
		if (!$this->stream->is(T_IF))
		{
			return;
		}
		$this->stream->replace([T_ELSEIF, 'elseif']);
		$this->unindentBlock($structure['offsetLeftBrace'] + 1, $structure['offsetRightBrace'] - 1);
		$this->stream->seek($structure['offsetConstruct']);
		$this->stream->remove();
		$this->removeWhitespaceBefore($this->stream->key());
	}

	/**
	* Optimize given structure and the other structures it contains
	*
	* @param  array $structure
	* @return void
	*/
	protected function optimizeStructure(array $structure)
	{
		$this->optimizeStructures($structure['structures']);

		if ($structure['isIf'] || $structure['isElseif'])
		{
			$this->markPreservedBraces($structure['offsetRightBrace']);
		}

		if ($this->canRemoveBracesFrom($structure))
		{
			if ($structure['isElse'])
			{
				$this->optimizeElse($structure);
			}
			$this->removeBraces($structure);
		}
	}

	/**
	* Optimize a list of parsed structures
	*
	* @param  array[] $structures
	* @return void
	*/
	protected function optimizeStructures(array $structures)
	{
		foreach ($structures as $structure)
		{
			$this->optimizeStructure($structure);
		}
	}

	/**
	* Parse the control structure starting at current offset
	*
	* @return array|false
	*/
	protected function parseControlStructure()
	{
		$structure = [
			'isElse'           => $this->stream->is(T_ELSE),
			'isElseif'         => $this->stream->is(T_ELSEIF),
			'isIf'             => $this->stream->is(T_IF),
			'offsetConstruct'  => $this->stream->key(),
			'offsetLeftBrace'  => null,
			'offsetRightBrace' => null,
			'statements'       => 0,
			'structures'       => []
		];

		if ($structure['isElse'])
		{
			$this->stream->next();
		}
		else
		{
			$this->skipParenthesizedExpression();
		}
		$this->stream->skipNoise();

		if ($this->stream->current() !== '{' || $this->isFollowedByDeclaraction())
		{
			return false;
		}

		$braces = 0;
		$structure['offsetLeftBrace'] = $this->stream->key();
		while ($this->stream->valid())
		{
			$token = $this->stream->current();
			if ($token === ';')
			{
				++$structure['statements'];
			}
			elseif ($token === '}')
			{
				--$braces;
				if (!$braces)
				{
					break;
				}
			}
			elseif ($this->isCurlyOpen())
			{
				++$braces;
			}
			elseif ($this->isControlStructure())
			{
				if (!$this->stream->isAny([T_ELSE, T_ELSEIF]))
				{
					++$structure['statements'];
				}

				$innerStructure = $this->parseControlStructure();
				if ($innerStructure)
				{
					$structure['structures'][] = $innerStructure;
				}
			}

			$this->stream->next();
		}
		$structure['offsetRightBrace'] = $this->stream->key();

		return $structure;
	}

	/**
	* Mark the offset of right braces that must be preserved
	*
	* Works by counting the number of consecutive braces between the starting point and the next
	* non-brace token. If the next token is a T_ELSE or T_ELSEIF and it does not immediately follow
	* current brace then its branch belongs to another conditional, which means the brace must be
	* preserved
	*
	* @param  integer $offset Offset of the first closing brace
	* @return void
	*/
	protected function markPreservedBraces($offset)
	{
		$braces = 0;
		$braceOffset = $offset;
		$isFollowedByElse = false;

		$this->stream->seek($offset);
		while ($this->stream->valid() && $this->stream->current() === '}')
		{
			++$braces;
			$braceOffset = $this->stream->key();

			$this->stream->next();
			$this->stream->skipNoise();
			if ($this->stream->valid())
			{
				$isFollowedByElse = $this->stream->isAny([T_ELSE, T_ELSEIF]);
			}
		}

		if ($isFollowedByElse && $braces > 1)
		{
			$this->preservedBraces[$braceOffset] = 1;
		}
	}

	/**
	* Remove braces from given structure
	*
	* @param  array $structure
	* @return void
	*/
	protected function removeBraces(array $structure)
	{
		// Replace the opening brace with a semicolon if the control structure is empty, remove the
		// brace if possible or replace it with whitespace otherwise (e.g. in "else foreach")
		$this->stream->seek($structure['offsetLeftBrace']);
		if (!$structure['statements'])
		{
			$this->stream->replace(';');
		}
		elseif ($this->stream->canRemoveCurrentToken())
		{
			$this->stream->remove();
		}
		else
		{
			$this->stream->replace([T_WHITESPACE, ' ']);
		}

		// Remove the closing brace
		$this->stream->seek($structure['offsetRightBrace']);
		$this->stream->remove();

		// Remove the whitespace before the braces if possible. This is purely cosmetic
		$this->removeWhitespaceBefore($structure['offsetLeftBrace']);
		$this->removeWhitespaceBefore($structure['offsetRightBrace']);
	}

	/**
	* Remove the whitespace before given offset, if possible
	*
	* @return void
	*/
	protected function removeWhitespaceBefore($offset)
	{
		if (!isset($this->stream[$offset - 1]))
		{
			return;
		}

		$this->stream->seek($offset - 1);
		if ($this->stream->is(T_WHITESPACE) && $this->stream->canRemoveCurrentToken())
		{
			$this->stream->remove();
		}
	}

	/**
	* Skip the condition of a control structure
	*
	* @return void
	*/
	protected function skipParenthesizedExpression()
	{
		// Reach the opening parenthesis
		$this->stream->skipToToken('(');

		// Iterate through tokens until we have a match for every left parenthesis
		$parens = 0;
		$this->stream->next();
		while ($this->stream->valid())
		{
			$token = $this->stream->current();
			if ($token === ')')
			{
				if ($parens)
				{
					--$parens;
				}
				else
				{
					// Skip the last parenthesis
					$this->stream->next();
					break;
				}
			}
			elseif ($token === '(')
			{
				++$parens;
			}
			$this->stream->next();
		}
	}

	/**
	* Remove one tab's worth of indentation off a range of PHP tokens
	*
	* @param  integer $start  Offset of the first token to unindent
	* @param  integer $end    Offset of the last token to unindent
	* @return void
	*/
	protected function unindentBlock($start, $end)
	{
		$this->stream->seek($start);
		$anchor = "\n";
		while ($this->stream->key() <= $end)
		{
			$token = $this->stream->current();
			if ($this->stream->isNoise())
			{
				$token[1] = preg_replace('((' . $anchor . ")(?:    |\t))", '$1', $token[1]);
				$this->stream->replace($token);
			}
			$anchor = ($token[0] === T_COMMENT) ? "^|\n" : "\n";
			$this->stream->next();
		}
	}
}

1			<?php
2
3			/**
4			* @package s9e\SourceOptimizer
5			* @copyright Copyright (c) 2014-2018 The s9e Authors
6			* @license http://www.opensource.org/licenses/mit-license.php The MIT License
7			*/
8			namespace s9e\SourceOptimizer\Passes;
9
10			/**
11			* Optimizes the control structures of a script.
12			*
13			* Removes braces in control structures wherever possible. Prevents the generation of EXT_STMT
14			* opcodes where they're not strictly required.
15			*/
16			class RemoveBraces extends AbstractPass
17			{
18			/**
19			* @var array Offsets of braces that need to be preserved (offsets used as keys)
20			*/
21			protected $preservedBraces;
22
23			/**
24			* {@inheritdoc}
25			*/
26	39		public function optimizeStream()
27			{
28	39		$this->preservedBraces = [];
29	39		$structures = [];
30	39		while ($this->stream->valid())
31			{
32	39		if ($this->isControlStructure())
33			{
34	39		$structure = $this->parseControlStructure();
35	39		if ($structure)
36			{
37	35		$structures[] = $structure;
38			}
39			}
40	39		$this->stream->next();
41			}
42
43	39		$this->optimizeStructures($structures);
44	39		}
45
46			/**
47			* Test whether the given structure's braces can be removed
48			*
49			* @param array $structure
50			* @return bool
51			*/
52	35		protected function canRemoveBracesFrom(array $structure)
53			{
54	35		return ($structure['statements'] <= 1 && !isset($this->preservedBraces[$structure['offsetRightBrace']]));
55			}
56
57			/**
58			* Test whether the token at current offset is a control structure
59			*
60			* NOTE: we ignore T_DO since the braces are not optional
61			*
62			* @return bool
63			*/
64	39		protected function isControlStructure()
65			{
66	39		return $this->stream->isAny([T_ELSE, T_ELSEIF, T_FOR, T_FOREACH, T_IF, T_WHILE]);
67			}
68
69			/**
70			* Test whether the token at current offset is an open curly brace
71			*
72			* @return bool
73			*/
74	35		protected function isCurlyOpen()
75			{
76	35		return ($this->stream->current() === '{' \|\| $this->stream->isAny([T_CURLY_OPEN, T_DOLLAR_OPEN_CURLY_BRACES]));
77			}
78
79			/**
80			* Test whether current token is followed by a function or class-related declaration
81			*
82			* @return bool
83			*/
84	37		protected function isFollowedByDeclaraction()
85			{
86	37		$keywords = [T_ABSTRACT, T_CLASS, T_FINAL, T_FUNCTION, T_INTERFACE, T_TRAIT];
87
88	37		$offset = $this->stream->key();
89	37		$this->stream->next();
90	37		$this->stream->skipNoise();
91	37		$isFollowedByFunction = ($this->stream->valid() && $this->stream->isAny($keywords));
92	37		$this->stream->seek($offset);
93
94	37		return $isFollowedByFunction;
95			}
96
97			/**
98			* Optimize given T_ELSE structure
99			*
100			* @param array $structure
101			* @return void
102			*/
103	21		protected function optimizeElse(array $structure)
104			{
105	21		$this->stream->seek($structure['offsetLeftBrace']);
106	21		$this->stream->next();
107	21		$this->stream->skipNoise();
108	21		if (!$this->stream->is(T_IF))
109			{
110	17		return;
111			}
112	7		$this->stream->replace([T_ELSEIF, 'elseif']);
113	7		$this->unindentBlock($structure['offsetLeftBrace'] + 1, $structure['offsetRightBrace'] - 1);
114	7		$this->stream->seek($structure['offsetConstruct']);
115	7		$this->stream->remove();
116	7		$this->removeWhitespaceBefore($this->stream->key());
117	7		}
118
119			/**
120			* Optimize given structure and the other structures it contains
121			*
122			* @param array $structure
123			* @return void
124			*/
125	35		protected function optimizeStructure(array $structure)
126			{
127	35		$this->optimizeStructures($structure['structures']);
128
129	35		if ($structure['isIf'] \|\| $structure['isElseif'])
130			{
131	31		$this->markPreservedBraces($structure['offsetRightBrace']);
132			}
133
134	35		if ($this->canRemoveBracesFrom($structure))
135			{
136	31		if ($structure['isElse'])
137			{
138	21		$this->optimizeElse($structure);
139			}
140	31		$this->removeBraces($structure);
141			}
142	35		}
143
144			/**
145			* Optimize a list of parsed structures
146			*
147			* @param array[] $structures
148			* @return void
149			*/
150	39		protected function optimizeStructures(array $structures)
151			{
152	39		foreach ($structures as $structure)
153			{
154	35		$this->optimizeStructure($structure);
155			}
156	39		}
157
158			/**
159			* Parse the control structure starting at current offset
160			*
161			* @return array\|false
162			*/
163	39		protected function parseControlStructure()
164			{
165			$structure = [
166	39		'isElse' => $this->stream->is(T_ELSE),
167	39		'isElseif' => $this->stream->is(T_ELSEIF),
168	39		'isIf' => $this->stream->is(T_IF),
169	39		'offsetConstruct' => $this->stream->key(),
170			'offsetLeftBrace' => null,
171			'offsetRightBrace' => null,
172	39		'statements' => 0,
173			'structures' => []
174			];
175
176	39		if ($structure['isElse'])
177			{
178	24		$this->stream->next();
179			}
180			else
181			{
182	39		$this->skipParenthesizedExpression();
183			}
184	39		$this->stream->skipNoise();
185
186	39		if ($this->stream->current() !== '{' \|\| $this->isFollowedByDeclaraction())
187			{
188	4		return false;
189			}
190
191	35		$braces = 0;
192	35		$structure['offsetLeftBrace'] = $this->stream->key();
193	35		while ($this->stream->valid())
194			{
195	35		$token = $this->stream->current();
196	35		if ($token === ';')
197			{
198	29		++$structure['statements'];
199			}
200	35		elseif ($token === '}')
201			{
202	35		--$braces;
203	35		if (!$braces)
204			{
205	35		break;
206			}
207			}
208	35		elseif ($this->isCurlyOpen())
209			{
210	35		++$braces;
211			}
212	33		elseif ($this->isControlStructure())
213			{
214	18	View Code Duplication	if (!$this->stream->isAny([T_ELSE, T_ELSEIF]))
215			{
216	18		++$structure['statements'];
217			}
218
219	18		$innerStructure = $this->parseControlStructure();
220	18		if ($innerStructure)
221			{
222	18		$structure['structures'][] = $innerStructure;
223			}
224			}
225
226	35		$this->stream->next();
227			}
228	35		$structure['offsetRightBrace'] = $this->stream->key();
229
230	35		return $structure;
231			}
232
233			/**
234			* Mark the offset of right braces that must be preserved
235			*
236			* Works by counting the number of consecutive braces between the starting point and the next
237			* non-brace token. If the next token is a T_ELSE or T_ELSEIF and it does not immediately follow
238			* current brace then its branch belongs to another conditional, which means the brace must be
239			* preserved
240			*
241			* @param integer $offset Offset of the first closing brace
242			* @return void
243			*/
244	31		protected function markPreservedBraces($offset)
245			{
246	31		$braces = 0;
247	31		$braceOffset = $offset;
248	31		$isFollowedByElse = false;
249
250	31		$this->stream->seek($offset);
251	31		while ($this->stream->valid() && $this->stream->current() === '}')
252			{
253	31		++$braces;
254	31		$braceOffset = $this->stream->key();
255
256	31		$this->stream->next();
257	31		$this->stream->skipNoise();
258	31	View Code Duplication	if ($this->stream->valid())
259			{
260	23		$isFollowedByElse = $this->stream->isAny([T_ELSE, T_ELSEIF]);
261			}
262			}
263
264	31		if ($isFollowedByElse && $braces > 1)
265			{
266	5		$this->preservedBraces[$braceOffset] = 1;
267			}
268	31		}
269
270			/**
271			* Remove braces from given structure
272			*
273			* @param array $structure
274			* @return void
275			*/
276	31		protected function removeBraces(array $structure)
277			{
278			// Replace the opening brace with a semicolon if the control structure is empty, remove the
279			// brace if possible or replace it with whitespace otherwise (e.g. in "else foreach")
280	31		$this->stream->seek($structure['offsetLeftBrace']);
281	31		if (!$structure['statements'])
282			{
283	15		$this->stream->replace(';');
284			}
285	25		elseif ($this->stream->canRemoveCurrentToken())
286			{
287	23		$this->stream->remove();
288			}
289			else
290			{
291	7		$this->stream->replace([T_WHITESPACE, ' ']);
292			}
293
294			// Remove the closing brace
295	31		$this->stream->seek($structure['offsetRightBrace']);
296	31		$this->stream->remove();
297
298			// Remove the whitespace before the braces if possible. This is purely cosmetic
299	31		$this->removeWhitespaceBefore($structure['offsetLeftBrace']);
300	31		$this->removeWhitespaceBefore($structure['offsetRightBrace']);
301	31		}
302
303			/**
304			* Remove the whitespace before given offset, if possible
305			*
306			* @return void
307			*/
308	31		protected function removeWhitespaceBefore($offset)
309			{
310	31		if (!isset($this->stream[$offset - 1]))
311			{
312	5		return;
313			}
314
315	31		$this->stream->seek($offset - 1);
316	31		if ($this->stream->is(T_WHITESPACE) && $this->stream->canRemoveCurrentToken())
317			{
318	17		$this->stream->remove();
319			}
320	31		}
321
322			/**
323			* Skip the condition of a control structure
324			*
325			* @return void
326			*/
327	39		protected function skipParenthesizedExpression()
328			{
329			// Reach the opening parenthesis
330	39		$this->stream->skipToToken('(');
331
332			// Iterate through tokens until we have a match for every left parenthesis
333	39		$parens = 0;
334	39		$this->stream->next();
335	39		while ($this->stream->valid())
336			{
337	39		$token = $this->stream->current();
338	39		if ($token === ')')
339			{
340	39		if ($parens)
341			{
342	1		--$parens;
343			}
344			else
345			{
346			// Skip the last parenthesis
347	39		$this->stream->next();
348	39		break;
349			}
350			}
351	39		elseif ($token === '(')
352			{
353	1		++$parens;
354			}
355	39		$this->stream->next();
356			}
357	39		}
358
359			/**
360			* Remove one tab's worth of indentation off a range of PHP tokens
361			*
362			* @param integer $start Offset of the first token to unindent
363			* @param integer $end Offset of the last token to unindent
364			* @return void
365			*/
366	7		protected function unindentBlock($start, $end)
367			{
368	7		$this->stream->seek($start);
369	7		$anchor = "\n";
370	7		while ($this->stream->key() <= $end)
371			{
372	7		$token = $this->stream->current();
373	7		if ($this->stream->isNoise())
374			{
375	6		$token[1] = preg_replace('((' . $anchor . ")(?: \|\t))", '$1', $token[1]);
376	6		$this->stream->replace($token);
377			}
378	7		$anchor = ($token[0] === T_COMMENT) ? "^\|\n" : "\n";
379	7		$this->stream->next();
380			}
381			}
382			}

s9e / SourceOptimizer

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RemoveBraces::optimizeStructure() B

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