Improve robustness of injecting styles to prevent inadvertant display

syntax-highlighting-code-block.php

@@ -332,7 +332,7 @@ function get_styles( $attributes ) {
  // a stylesheet is printed the first time, subsequent calls to wp_print_styles() will no-op.
  ob_start();
  wp_print_styles( FRONTEND_STYLE_HANDLE );
- $styles = ob_get_clean();
+ $styles = trim( ob_get_clean() );
 
  // Include line-number styles if requesting to show lines.
  if ( ! $added_inline_style ) {
@@ -374,7 +374,7 @@ function get_styles( $attributes ) {
  * @return string Highlighted content.
  */
 function render_block( $attributes, $content ) {
- $pattern = '(?P<before><pre.*?><code.*?>)';
+ $pattern = '(?P<pre_start_tag><pre[^>]*?>)(?P<code_start_tag><code[^>]*?>)';
  $pattern .= '(?P<content>.*)';
  $pattern .= '</code></pre>';
 
@@ -394,7 +394,15 @@ function render_block( $attributes, $content ) {
 
  $end_tags = '</code></div></pre>';
 
- $inject_classes = function( $start_tags, $attributes ) {
+ /**
+ * Inject class names and styles into the
+ *
+ * @param string $pre_start_tag The `<pre>` start tag.
+ * @param string $code_start_tag The `<code>` start tag.
+ * @param array $attributes Attributes.
+ * @return string Injected markup.
+ */
+ $inject_markup = function( $pre_start_tag, $code_start_tag, $attributes ) {
  $added_classes = 'hljs';
 
  if ( $attributes['language'] ) {
@@ -413,23 +421,23 @@ function render_block( $attributes, $content ) {
  $added_classes .= ' shcb-wrap-lines';
  }
 
- $start_tags = preg_replace(
- '/(<code[^>]*class=")/',
+ $code_start_tag = preg_replace(
+ '/(<code[^>]*class=["\'])/',
  '$1 ' . esc_attr( $added_classes ),
- $start_tags,
+ $code_start_tag,
  1,
  $count
  );
  if ( 0 === $count ) {
- $start_tags = preg_replace(
- '/(?<=<code)(?=>)/',
+ $code_start_tag = preg_replace(
+ '/(?<=<code\b)/',
  sprintf( ' class="%s"', esc_attr( $added_classes ) ),
- $start_tags,
+ $code_start_tag,
  1
  );
  }
 
- return preg_replace( '/(<pre[^>]*>)(<code)/', '$1<div>$2', $start_tags, 1 );
+ return $pre_start_tag . get_styles( $attributes ) . '<div>' . $code_start_tag;
  };
 
  /**
@@ -443,7 +451,7 @@ function render_block( $attributes, $content ) {
  $highlighted = get_transient( $transient_key );
 
  if ( ! DEVELOPMENT_MODE && $highlighted && isset( $highlighted['content'] ) ) {
- return get_styles( $attributes ) . $inject_classes( $matches['before'], $highlighted['attributes'] ) . $highlighted['content'] . $end_tags;
+ return $inject_markup( $matches['pre_start_tag'], $matches['code_start_tag'], $highlighted['attributes'] ) . $highlighted['content'] . $end_tags;
  }
 
  try {
@@ -496,14 +504,11 @@ function render_block( $attributes, $content ) {
  }
  }
 
- set_transient( $transient_key, compact( 'content', 'attributes' ), MONTH_IN_SECONDS );
-
- $matches['before'] = $inject_classes(
- $matches['before'],
- $attributes
- );
+ if ( ! DEVELOPMENT_MODE ) {
+ set_transient( $transient_key, compact( 'content', 'attributes' ), MONTH_IN_SECONDS );
+ }
 
- return get_styles( $attributes ) . $matches['before'] . $content . $end_tags;
+ return $inject_markup( $matches['pre_start_tag'], $matches['code_start_tag'], $attributes ) . $content . $end_tags;
  } catch ( Exception $e ) {
  return sprintf(
  '<!-- %s(%s): %s -->%s',