ControlStructuresOptimizer::removeBracesInCurrentContext() - Code Metrics - Inspection of "MediaEmbed: updated Amazon" - s9e/TextFormatter - Measure and Improve Code Quality continuously with Scrutinizer

Completed

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by Josh

created 2018-06-23 23:40 UTC

removeBracesInCurrentContext() B

↳ Parent: ControlStructuresOptimizer

Complexity

Conditions	10
Paths	24

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	56
rs	7.0933
c	0
b	0
f	0
cc	10
nc	24
nop	0

How to fix Long Method Complexity

<?php

/**
* @package   s9e\TextFormatter
* @copyright Copyright (c) 2010-2018 The s9e Authors
* @license   http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\TextFormatter\Configurator\RendererGenerators\PHP;

/**
* Optimize the control structures of a script
*
* Removes brackets in control structures wherever possible. Prevents the generation of EXT_STMT
* opcodes where they're not strictly required.
*/
class ControlStructuresOptimizer extends AbstractOptimizer
{
	/**
	* @var integer Number of braces encountered in current source
	*/
	protected $braces;

	/**
	* @var array Current context
	*/
	protected $context;

	/**
	* Test whether current block ends with an if or elseif control structure
	*
	* @return bool
	*/
	protected function blockEndsWithIf()
	{
		return in_array($this->context['lastBlock'], [T_IF, T_ELSEIF], true);
	}

	/**
	* Test whether the token at current index is a control structure
	*
	* @return bool
	*/
	protected function isControlStructure()
	{
		return in_array(
			$this->tokens[$this->i][0],
			[T_ELSE, T_ELSEIF, T_FOR, T_FOREACH, T_IF, T_WHILE],
			true
		);
	}

	/**
	* Test whether current block is followed by an elseif/else structure
	*
	* @return bool
	*/
	protected function isFollowedByElse()
	{
		if ($this->i > $this->cnt - 4)
		{
			// It doesn't have room for another block
			return false;
		}

		// Compute the index of the next non-whitespace token
		$k = $this->i + 1;

		if ($this->tokens[$k][0] === T_WHITESPACE)
		{
			++$k;
		}

		return in_array($this->tokens[$k][0], [T_ELSEIF, T_ELSE], true);
	}

	/**
	* Test whether braces must be preserved in current context
	*
	* @return bool
	*/
	protected function mustPreserveBraces()
	{
		// If current block ends with if/elseif and is followed by elseif/else, we must preserve
		// its braces to prevent it from merging with the outer elseif/else. IOW, we must preserve
		// the braces if "if{if{}}else" would become "if{if else}"
		return ($this->blockEndsWithIf() && $this->isFollowedByElse());
	}

	/**
	* Optimize control structures in stored tokens
	*
	* @return void
	*/
	protected function optimizeTokens()
	{
		while (++$this->i < $this->cnt)
		{
			if ($this->tokens[$this->i] === ';')
			{
				++$this->context['statements'];
			}
			elseif ($this->tokens[$this->i] === '{')
			{
				++$this->braces;
			}
			elseif ($this->tokens[$this->i] === '}')
			{
				if ($this->context['braces'] === $this->braces)
				{
					$this->processEndOfBlock();
				}

				--$this->braces;
			}
			elseif ($this->isControlStructure())
			{
				$this->processControlStructure();
			}
		}
	}

	/**
	* Process the control structure starting at current index
	*
	* @return void
	*/
	protected function processControlStructure()
	{
		// Save the index so we can rewind back to it in case of failure
		$savedIndex = $this->i;

		// Count this control structure in this context's statements unless it's an elseif/else
		// in which case it's already been counted as part of the if
		if (!in_array($this->tokens[$this->i][0], [T_ELSE, T_ELSEIF], true))
		{
			++$this->context['statements'];
		}

		// If the control structure is anything but an "else", skip its condition to reach the first
		// brace or statement
		if ($this->tokens[$this->i][0] !== T_ELSE)
		{
			$this->skipCondition();
		}

		$this->skipWhitespace();

		// Abort if this control structure does not use braces
		if ($this->tokens[$this->i] !== '{')
		{
			// Rewind all the way to the original token
			$this->i = $savedIndex;

			return;
		}

		++$this->braces;

		// Replacement for the first brace
		$replacement = [T_WHITESPACE, ''];

		// Add a space after "else" if the brace is removed and it's not followed by whitespace or a
		// variable
		if ($this->tokens[$savedIndex][0]  === T_ELSE
		 && $this->tokens[$this->i + 1][0] !== T_VARIABLE
		 && $this->tokens[$this->i + 1][0] !== T_WHITESPACE)
		{
			$replacement = [T_WHITESPACE, ' '];
		}

		// Record the token of the control structure (T_IF, T_WHILE, etc...) in the current context
		$this->context['lastBlock'] = $this->tokens[$savedIndex][0];

		// Create a new context
		$this->context = [
			'braces'      => $this->braces,
			'index'       => $this->i,
			'lastBlock'   => null,
			'parent'      => $this->context,
			'replacement' => $replacement,
			'savedIndex'  => $savedIndex,
			'statements'  => 0
		];
	}

	/**
	* Process the block ending at current index
	*
	* @return void
	*/
	protected function processEndOfBlock()
	{
		if ($this->context['statements'] < 2 && !$this->mustPreserveBraces())
		{
			$this->removeBracesInCurrentContext();
		}

		$this->context = $this->context['parent'];

		// Propagate the "lastBlock" property upwards to handle multiple nested if statements
		$this->context['parent']['lastBlock'] = $this->context['lastBlock'];
	}

	/**
	* Remove the braces surrounding current context
	*
	* @return void
	*/
	protected function removeBracesInCurrentContext()
	{
		// Replace the first brace with the saved replacement
		$this->tokens[$this->context['index']] = $this->context['replacement'];

		// Remove the second brace or replace it with a semicolon if there are no statements in this
		// block
		$this->tokens[$this->i] = ($this->context['statements']) ? [T_WHITESPACE, ''] : ';';

		// Remove the whitespace before braces. This is mainly cosmetic
		foreach ([$this->context['index'] - 1, $this->i - 1] as $tokenIndex)
		{
			if ($this->tokens[$tokenIndex][0] === T_WHITESPACE)
			{
				$this->tokens[$tokenIndex][1] = '';
			}
		}

		// Test whether the current block followed an else statement then test whether this
		// else was followed by an if
		if ($this->tokens[$this->context['savedIndex']][0] === T_ELSE)
		{
			$j = 1 + $this->context['savedIndex'];

			while ($this->tokens[$j][0] === T_WHITESPACE
			    || $this->tokens[$j][0] === T_COMMENT
			    || $this->tokens[$j][0] === T_DOC_COMMENT)
			{
				++$j;
			}

			if ($this->tokens[$j][0] === T_IF)
			{
				// Replace if with elseif
				$this->tokens[$j] = [T_ELSEIF, 'elseif'];

				// Remove the original else
				$j = $this->context['savedIndex'];
				$this->tokens[$j] = [T_WHITESPACE, ''];

				// Remove any whitespace before the original else
				if ($this->tokens[$j - 1][0] === T_WHITESPACE)
				{
					$this->tokens[$j - 1][1] = '';
				}

				// Unindent what was the else's content
				$this->unindentBlock($j, $this->i - 1);

				// Ensure that the brace after the now-removed "else" was not replaced with a space
				$this->tokens[$this->context['index']] = [T_WHITESPACE, ''];
			}
		}

		$this->changed = true;
	}

	/**
	* {@inheritdoc}
	*/
	protected function reset($php)
	{
		parent::reset($php);

		$this->braces  = 0;
		$this->context = [
			'braces'      => 0,
			'index'       => -1,
			'parent'      => [],
			'preventElse' => false,
			'savedIndex'  => 0,
			'statements'  => 0
		];
	}

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

		// Iterate through tokens until we have a match for every left parenthesis
		$parens = 0;
		while (++$this->i < $this->cnt)
		{
			if ($this->tokens[$this->i] === ')')
			{
				if ($parens)
				{
					--$parens;
				}
				else
				{
					break;
				}
			}
			elseif ($this->tokens[$this->i] === '(')
			{
				++$parens;
			}
		}
	}
}

1			<?php
2
3			/**
4			* @package s9e\TextFormatter
5			* @copyright Copyright (c) 2010-2018 The s9e Authors
6			* @license http://www.opensource.org/licenses/mit-license.php The MIT License
7			*/
8			namespace s9e\TextFormatter\Configurator\RendererGenerators\PHP;
9
10			/**
11			* Optimize the control structures of a script
12			*
13			* Removes brackets in control structures wherever possible. Prevents the generation of EXT_STMT
14			* opcodes where they're not strictly required.
15			*/
16			class ControlStructuresOptimizer extends AbstractOptimizer
17			{
18			/**
19			* @var integer Number of braces encountered in current source
20			*/
21			protected $braces;
22
23			/**
24			* @var array Current context
25			*/
26			protected $context;
27
28			/**
29			* Test whether current block ends with an if or elseif control structure
30			*
31			* @return bool
32			*/
33			protected function blockEndsWithIf()
34			{
35			return in_array($this->context['lastBlock'], [T_IF, T_ELSEIF], true);
36			}
37
38			/**
39			* Test whether the token at current index is a control structure
40			*
41			* @return bool
42			*/
43			protected function isControlStructure()
44			{
45			return in_array(
46			$this->tokens[$this->i][0],
47			[T_ELSE, T_ELSEIF, T_FOR, T_FOREACH, T_IF, T_WHILE],
48			true
49			);
50			}
51
52			/**
53			* Test whether current block is followed by an elseif/else structure
54			*
55			* @return bool
56			*/
57			protected function isFollowedByElse()
58			{
59			if ($this->i > $this->cnt - 4)
60			{
61			// It doesn't have room for another block
62			return false;
63			}
64
65			// Compute the index of the next non-whitespace token
66			$k = $this->i + 1;
67
68			if ($this->tokens[$k][0] === T_WHITESPACE)
69			{
70			++$k;
71			}
72
73			return in_array($this->tokens[$k][0], [T_ELSEIF, T_ELSE], true);
74			}
75
76			/**
77			* Test whether braces must be preserved in current context
78			*
79			* @return bool
80			*/
81			protected function mustPreserveBraces()
82			{
83			// If current block ends with if/elseif and is followed by elseif/else, we must preserve
84			// its braces to prevent it from merging with the outer elseif/else. IOW, we must preserve
85			// the braces if "if{if{}}else" would become "if{if else}"
86			return ($this->blockEndsWithIf() && $this->isFollowedByElse());
87			}
88
89			/**
90			* Optimize control structures in stored tokens
91			*
92			* @return void
93			*/
94			protected function optimizeTokens()
95			{
96			while (++$this->i < $this->cnt)
97			{
98			if ($this->tokens[$this->i] === ';')
99			{
100			++$this->context['statements'];
101			}
102			elseif ($this->tokens[$this->i] === '{')
103			{
104			++$this->braces;
105			}
106			elseif ($this->tokens[$this->i] === '}')
107			{
108			if ($this->context['braces'] === $this->braces)
109			{
110			$this->processEndOfBlock();
111			}
112
113			--$this->braces;
114			}
115			elseif ($this->isControlStructure())
116			{
117			$this->processControlStructure();
118			}
119			}
120			}
121
122			/**
123			* Process the control structure starting at current index
124			*
125			* @return void
126			*/
127			protected function processControlStructure()
128			{
129			// Save the index so we can rewind back to it in case of failure
130			$savedIndex = $this->i;
131
132			// Count this control structure in this context's statements unless it's an elseif/else
133			// in which case it's already been counted as part of the if
134			if (!in_array($this->tokens[$this->i][0], [T_ELSE, T_ELSEIF], true))
135			{
136			++$this->context['statements'];
137			}
138
139			// If the control structure is anything but an "else", skip its condition to reach the first
140			// brace or statement
141			if ($this->tokens[$this->i][0] !== T_ELSE)
142			{
143			$this->skipCondition();
144			}
145
146			$this->skipWhitespace();
147
148			// Abort if this control structure does not use braces
149			if ($this->tokens[$this->i] !== '{')
150			{
151			// Rewind all the way to the original token
152			$this->i = $savedIndex;
153
154			return;
155			}
156
157			++$this->braces;
158
159			// Replacement for the first brace
160			$replacement = [T_WHITESPACE, ''];
161
162			// Add a space after "else" if the brace is removed and it's not followed by whitespace or a
163			// variable
164			if ($this->tokens[$savedIndex][0] === T_ELSE
165			&& $this->tokens[$this->i + 1][0] !== T_VARIABLE
166			&& $this->tokens[$this->i + 1][0] !== T_WHITESPACE)
167			{
168			$replacement = [T_WHITESPACE, ' '];
169			}
170
171			// Record the token of the control structure (T_IF, T_WHILE, etc...) in the current context
172			$this->context['lastBlock'] = $this->tokens[$savedIndex][0];
173
174			// Create a new context
175			$this->context = [
176			'braces' => $this->braces,
177			'index' => $this->i,
178			'lastBlock' => null,
179			'parent' => $this->context,
180			'replacement' => $replacement,
181			'savedIndex' => $savedIndex,
182			'statements' => 0
183			];
184			}
185
186			/**
187			* Process the block ending at current index
188			*
189			* @return void
190			*/
191			protected function processEndOfBlock()
192			{
193			if ($this->context['statements'] < 2 && !$this->mustPreserveBraces())
194			{
195			$this->removeBracesInCurrentContext();
196			}
197
198			$this->context = $this->context['parent'];
199
200			// Propagate the "lastBlock" property upwards to handle multiple nested if statements
201			$this->context['parent']['lastBlock'] = $this->context['lastBlock'];
202			}
203
204			/**
205			* Remove the braces surrounding current context
206			*
207			* @return void
208			*/
209			protected function removeBracesInCurrentContext()
210			{
211			// Replace the first brace with the saved replacement
212			$this->tokens[$this->context['index']] = $this->context['replacement'];
213
214			// Remove the second brace or replace it with a semicolon if there are no statements in this
215			// block
216			$this->tokens[$this->i] = ($this->context['statements']) ? [T_WHITESPACE, ''] : ';';
217
218			// Remove the whitespace before braces. This is mainly cosmetic
219			foreach ([$this->context['index'] - 1, $this->i - 1] as $tokenIndex)
220			{
221			if ($this->tokens[$tokenIndex][0] === T_WHITESPACE)
222			{
223			$this->tokens[$tokenIndex][1] = '';
224			}
225			}
226
227			// Test whether the current block followed an else statement then test whether this
228			// else was followed by an if
229			if ($this->tokens[$this->context['savedIndex']][0] === T_ELSE)
230			{
231			$j = 1 + $this->context['savedIndex'];
232
233			while ($this->tokens[$j][0] === T_WHITESPACE
234			\|\| $this->tokens[$j][0] === T_COMMENT
235			\|\| $this->tokens[$j][0] === T_DOC_COMMENT)
236			{
237			++$j;
238			}
239
240			if ($this->tokens[$j][0] === T_IF)
241			{
242			// Replace if with elseif
243			$this->tokens[$j] = [T_ELSEIF, 'elseif'];
244
245			// Remove the original else
246			$j = $this->context['savedIndex'];
247			$this->tokens[$j] = [T_WHITESPACE, ''];
248
249			// Remove any whitespace before the original else
250			if ($this->tokens[$j - 1][0] === T_WHITESPACE)
251			{
252			$this->tokens[$j - 1][1] = '';
253			}
254
255			// Unindent what was the else's content
256			$this->unindentBlock($j, $this->i - 1);
257
258			// Ensure that the brace after the now-removed "else" was not replaced with a space
259			$this->tokens[$this->context['index']] = [T_WHITESPACE, ''];
260			}
261			}
262
263			$this->changed = true;
264			}
265
266			/**
267			* {@inheritdoc}
268			*/
269			protected function reset($php)
270			{
271			parent::reset($php);
272
273			$this->braces = 0;
274			$this->context = [
275			'braces' => 0,
276			'index' => -1,
277			'parent' => [],
278			'preventElse' => false,
279			'savedIndex' => 0,
280			'statements' => 0
281			];
282			}
283
284			/**
285			* Skip the condition of a control structure
286			*
287			* @return void
288			*/
289			protected function skipCondition()
290			{
291			// Reach the opening parenthesis
292			$this->skipToString('(');
293
294			// Iterate through tokens until we have a match for every left parenthesis
295			$parens = 0;
296			while (++$this->i < $this->cnt)
297			{
298			if ($this->tokens[$this->i] === ')')
299			{
300			if ($parens)
301			{
302			--$parens;
303			}
304			else
305			{
306			break;
307			}
308			}
309			elseif ($this->tokens[$this->i] === '(')
310			{
311			++$parens;
312			}
313			}
314			}
315			}

s9e / TextFormatter

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removeBracesInCurrentContext() B

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