CssConcatenator.php
162 lines
| 1 | <?php |
| 2 | |
| 3 | declare (strict_types=1); |
| 4 | namespace ProfilePressVendor\Pelago\Emogrifier\Utilities; |
| 5 | |
| 6 | /** |
| 7 | * Facilitates building a CSS string by appending rule blocks one at a time, checking whether the media query, |
| 8 | * selectors, or declarations block are the same as those from the preceding block and combining blocks in such cases. |
| 9 | * |
| 10 | * Example: |
| 11 | * |
| 12 | * ```php |
| 13 | * $concatenator = new CssConcatenator(); |
| 14 | * $concatenator->append(['body'], 'color: blue;'); |
| 15 | * $concatenator->append(['body'], 'font-size: 16px;'); |
| 16 | * $concatenator->append(['p'], 'margin: 1em 0;'); |
| 17 | * $concatenator->append(['ul', 'ol'], 'margin: 1em 0;'); |
| 18 | * $concatenator->append(['body'], 'font-size: 14px;', '@media screen and (max-width: 400px)'); |
| 19 | * $concatenator->append(['ul', 'ol'], 'margin: 0.75em 0;', '@media screen and (max-width: 400px)'); |
| 20 | * $css = $concatenator->getCss(); |
| 21 | * ``` |
| 22 | * |
| 23 | * `$css` (if unminified) would contain the following CSS: |
| 24 | * |
| 25 | * ```css |
| 26 | * body { |
| 27 | * color: blue; |
| 28 | * font-size: 16px; |
| 29 | * } |
| 30 | * p, ul, ol { |
| 31 | * margin: 1em 0; |
| 32 | * } |
| 33 | * |
| 34 | * @media screen and (max-width: 400px) { |
| 35 | * body { |
| 36 | * font-size: 14px; |
| 37 | * } |
| 38 | * ul, ol { |
| 39 | * margin: 0.75em 0; |
| 40 | * } |
| 41 | * } |
| 42 | * ``` |
| 43 | * |
| 44 | * @internal |
| 45 | */ |
| 46 | final class CssConcatenator |
| 47 | { |
| 48 | /** |
| 49 | * Array of media rules in order. Each element is an object with the following properties: |
| 50 | * - `media` - The media query string, e.g. `@media screen and (max-width:639px)`, or an empty string for |
| 51 | * rules not within a media query block; |
| 52 | * - `ruleBlocks` - Array of rule blocks in order, where each element is an object with the following properties: |
| 53 | * - `selectorsAsKeys` - Array whose keys are selectors for the rule block (values are of no significance); |
| 54 | * - `declarationsBlock` - The property declarations, e.g. `margin-top: 0.5em; padding: 0`. |
| 55 | * |
| 56 | * @var list<object{ |
| 57 | * media: string, |
| 58 | * ruleBlocks: list<object{ |
| 59 | * selectorsAsKeys: array<non-empty-string, array-key>, |
| 60 | * declarationsBlock: string |
| 61 | * }> |
| 62 | * }> |
| 63 | */ |
| 64 | private $mediaRules = []; |
| 65 | /** |
| 66 | * Appends a declaration block to the CSS. |
| 67 | * |
| 68 | * @param array<array-key, string> $selectors |
| 69 | * array of selectors for the rule, e.g. `["ul", "ol", "p:first-child"]` |
| 70 | * @param string $declarationsBlock |
| 71 | * the property declarations, e.g. `margin-top: 0.5em; padding: 0` |
| 72 | * @param string $media |
| 73 | * the media query for the rule, e.g. `@media screen and (max-width:639px)`, or an empty string if none |
| 74 | */ |
| 75 | public function append(array $selectors, string $declarationsBlock, string $media = ''): void |
| 76 | { |
| 77 | $selectorsAsKeys = \array_flip($selectors); |
| 78 | $mediaRule = $this->getOrCreateMediaRuleToAppendTo($media); |
| 79 | $ruleBlocks = $mediaRule->ruleBlocks; |
| 80 | $lastRuleBlock = \end($ruleBlocks); |
| 81 | $hasSameDeclarationsAsLastRule = \is_object($lastRuleBlock) && $declarationsBlock === $lastRuleBlock->declarationsBlock; |
| 82 | if ($hasSameDeclarationsAsLastRule) { |
| 83 | $lastRuleBlock->selectorsAsKeys += $selectorsAsKeys; |
| 84 | } else { |
| 85 | $lastRuleBlockSelectors = \is_object($lastRuleBlock) ? $lastRuleBlock->selectorsAsKeys : []; |
| 86 | $hasSameSelectorsAsLastRule = \is_object($lastRuleBlock) && self::hasEquivalentSelectors($selectorsAsKeys, $lastRuleBlockSelectors); |
| 87 | if ($hasSameSelectorsAsLastRule) { |
| 88 | $lastDeclarationsBlockWithoutSemicolon = \rtrim(\rtrim($lastRuleBlock->declarationsBlock), ';'); |
| 89 | $lastRuleBlock->declarationsBlock = $lastDeclarationsBlockWithoutSemicolon . ';' . $declarationsBlock; |
| 90 | } else { |
| 91 | $mediaRule->ruleBlocks[] = (object) \compact('selectorsAsKeys', 'declarationsBlock'); |
| 92 | } |
| 93 | } |
| 94 | } |
| 95 | public function getCss(): string |
| 96 | { |
| 97 | return \implode('', \array_map([self::class, 'getMediaRuleCss'], $this->mediaRules)); |
| 98 | } |
| 99 | /** |
| 100 | * @param string $media The media query for rules to be appended, e.g. `@media screen and (max-width:639px)`, |
| 101 | * or an empty string if none. |
| 102 | * |
| 103 | * @return object{ |
| 104 | * media: string, |
| 105 | * ruleBlocks: list<object{ |
| 106 | * selectorsAsKeys: array<non-empty-string, array-key>, |
| 107 | * declarationsBlock: string |
| 108 | * }> |
| 109 | * } |
| 110 | */ |
| 111 | private function getOrCreateMediaRuleToAppendTo(string $media): object |
| 112 | { |
| 113 | $lastMediaRule = \end($this->mediaRules); |
| 114 | if (\is_object($lastMediaRule) && $media === $lastMediaRule->media) { |
| 115 | return $lastMediaRule; |
| 116 | } |
| 117 | $newMediaRule = (object) ['media' => $media, 'ruleBlocks' => []]; |
| 118 | $this->mediaRules[] = $newMediaRule; |
| 119 | return $newMediaRule; |
| 120 | } |
| 121 | /** |
| 122 | * Tests if two sets of selectors are equivalent (i.e. the same selectors, possibly in a different order). |
| 123 | * |
| 124 | * @param array<string, array-key> $selectorsAsKeys1 |
| 125 | * array in which the selectors are the keys, and the values are of no significance |
| 126 | * @param array<string, array-key> $selectorsAsKeys2 another such array |
| 127 | */ |
| 128 | private static function hasEquivalentSelectors(array $selectorsAsKeys1, array $selectorsAsKeys2): bool |
| 129 | { |
| 130 | return \count($selectorsAsKeys1) === \count($selectorsAsKeys2) && \count($selectorsAsKeys1) === \count($selectorsAsKeys1 + $selectorsAsKeys2); |
| 131 | } |
| 132 | /** |
| 133 | * @param object{ |
| 134 | * media: string, |
| 135 | * ruleBlocks: array<int, object{ |
| 136 | * selectorsAsKeys: array<string, array-key>, |
| 137 | * declarationsBlock: string |
| 138 | * }> |
| 139 | * } $mediaRule |
| 140 | */ |
| 141 | private static function getMediaRuleCss(object $mediaRule): string |
| 142 | { |
| 143 | $ruleBlocks = $mediaRule->ruleBlocks; |
| 144 | $css = \implode('', \array_map([self::class, 'getRuleBlockCss'], $ruleBlocks)); |
| 145 | $media = $mediaRule->media; |
| 146 | if ($media !== '') { |
| 147 | $css = $media . '{' . $css . '}'; |
| 148 | } |
| 149 | return $css; |
| 150 | } |
| 151 | /** |
| 152 | * @param object{selectorsAsKeys: array<string, array-key>, declarationsBlock: string} $ruleBlock |
| 153 | */ |
| 154 | private static function getRuleBlockCss(object $ruleBlock): string |
| 155 | { |
| 156 | $selectorsAsKeys = $ruleBlock->selectorsAsKeys; |
| 157 | $selectors = \array_keys($selectorsAsKeys); |
| 158 | $declarationsBlock = $ruleBlock->declarationsBlock; |
| 159 | return \implode(',', $selectors) . '{' . $declarationsBlock . '}'; |
| 160 | } |
| 161 | } |
| 162 |