File Toolkit/Core/Indentation.php

1:	<?php declare(strict_types=1);
2:
3:	namespace Salient\Core;
4:
5:	use Salient\Utility\File;
6:	use Stringable;
7:
8:	/**
9:	* @api
10:	*/
11:	final class Indentation
12:	{
13:	/** @readonly */
14:	public bool $InsertSpaces;
15:	/** @readonly */
16:	public int $TabSize;
17:
18:	public function __construct(bool $insertSpaces, int $tabSize)
19:	{
20:	$this->InsertSpaces = $insertSpaces;
21:	$this->TabSize = $tabSize;
22:	}
23:
24:	/**
25:	* Guess the indentation used in a file or stream
26:	*
27:	* Derived from VS Code's `indentationGuesser`.
28:	*
29:	* Returns `$default` if `$resource` appears to use the default indentation.
30:	*
31:	* @param Stringable\|string\|resource $resource
32:	* @param Stringable\|string\|null $uri
33:	*
34:	* @link https://github.com/microsoft/vscode/blob/860d67064a9c1ef8ce0c8de35a78bea01033f76c/src/vs/editor/common/model/indentationGuesser.ts
35:	*/
36:	public static function from(
37:	$resource,
38:	?self $default = null,
39:	bool $alwaysGuessTabSize = false,
40:	$uri = null
41:	): self {
42:	$handle = File::maybeOpen($resource, 'r', $close, $uri);
43:
44:	$lines = 0;
45:	$linesWithTabs = 0;
46:	$linesWithSpaces = 0;
47:	$diffSpacesCount = [2 => 0, 0, 0, 0, 0, 0, 0];
48:
49:	$prevLine = '';
50:	$prevOffset = 0;
51:	while ($lines < 10000) {
52:	$line = @fgets($handle);
53:	if ($line === false) {
54:	File::checkEof($handle, $uri);
55:	break;
56:	}
57:
58:	$lines++;
59:
60:	$line = rtrim($line);
61:	if ($line === '') {
62:	continue;
63:	}
64:
65:	$length = strlen($line);
66:	$spaces = 0;
67:	$tabs = 0;
68:	for ($offset = 0; $offset < $length; $offset++) {
69:	if ($line[$offset] === "\t") {
70:	$tabs++;
71:	} elseif ($line[$offset] === ' ') {
72:	$spaces++;
73:	} else {
74:	break;
75:	}
76:	}
77:
78:	if ($tabs) {
79:	$linesWithTabs++;
80:	} elseif ($spaces > 1) {
81:	$linesWithSpaces++;
82:	}
83:
84:	$minOffset = $prevOffset < $offset ? $prevOffset : $offset;
85:	for ($i = 0; $i < $minOffset; $i++) {
86:	if ($prevLine[$i] !== $line[$i]) {
87:	break;
88:	}
89:	}
90:
91:	$prevLineSpaces = 0;
92:	$prevLineTabs = 0;
93:	for ($j = $i; $j < $prevOffset; $j++) {
94:	if ($prevLine[$j] === ' ') {
95:	$prevLineSpaces++;
96:	} else {
97:	$prevLineTabs++;
98:	}
99:	}
100:
101:	$lineSpaces = 0;
102:	$lineTabs = 0;
103:	for ($j = $i; $j < $offset; $j++) {
104:	if ($line[$j] === ' ') {
105:	$lineSpaces++;
106:	} else {
107:	$lineTabs++;
108:	}
109:	}
110:
111:	$_prevLine = $prevLine;
112:	$_prevOffset = $prevOffset;
113:	$_line = $line;
114:
115:	$prevLine = $line;
116:	$prevOffset = $offset;
117:
118:	if (
119:	($prevLineSpaces && $prevLineTabs)
120:	\|\| ($lineSpaces && $lineTabs)
121:	) {
122:	continue;
123:	}
124:
125:	$diffSpaces = abs($prevLineSpaces - $lineSpaces);
126:	$diffTabs = abs($prevLineTabs - $lineTabs);
127:	if (!$diffTabs) {
128:	// Skip if the difference could be alignment-related and doesn't
129:	// match the file's default indentation
130:	if (
131:	$diffSpaces
132:	&& $lineSpaces
133:	&& $lineSpaces - 1 < strlen($_prevLine)
134:	&& $_line[$lineSpaces] !== ' '
135:	&& $_prevLine[$lineSpaces - 1] === ' '
136:	&& $_prevLine[-1] === ','
137:	&& !(
138:	$default
139:	&& $default->InsertSpaces
140:	&& $default->TabSize === $diffSpaces
141:	)
142:	) {
143:	$prevLine = $_prevLine;
144:	$prevOffset = $_prevOffset;
145:	continue;
146:	}
147:	} elseif ($diffSpaces % $diffTabs === 0) {
148:	$diffSpaces /= $diffTabs;
149:	} else {
150:	continue;
151:	}
152:
153:	if ($diffSpaces > 1 && $diffSpaces <= 8) {
154:	$diffSpacesCount[$diffSpaces]++;
155:	}
156:	}
157:
158:	$insertSpaces = $linesWithTabs === $linesWithSpaces
159:	? $default->InsertSpaces ?? true
160:	: $linesWithTabs < $linesWithSpaces;
161:
162:	$tabSize = $default->TabSize ?? 4;
163:
164:	// Only guess tab size if inserting spaces
165:	if ($insertSpaces \|\| $alwaysGuessTabSize) {
166:	$count = 0;
167:	foreach ([2, 4, 6, 8, 3, 5, 7] as $diffSpaces) {
168:	if ($diffSpacesCount[$diffSpaces] > $count) {
169:	$tabSize = $diffSpaces;
170:	$count = $diffSpacesCount[$diffSpaces];
171:	}
172:	}
173:	}
174:
175:	if ($close) {
176:	File::close($handle, $uri);
177:	}
178:
179:	if (
180:	$default
181:	&& $default->InsertSpaces === $insertSpaces
182:	&& $default->TabSize === $tabSize
183:	) {
184:	return $default;
185:	}
186:
187:	return new self($insertSpaces, $tabSize);
188:	}
189:	}
190:

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