WP_Text_Diff_Renderer_Table::interleave_changed_lines( array $orig, array $final ): array

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$origarray

Lines of the original version of the text.

$finalarray

Lines of the final version of the text.

Return value

array

Array containing results of comparing the original text to the final text.

• $orig_matchesarray

  Associative array of original matches. Index == row number of $orig, value == corresponding row number of that same line in $final or 'x' if there is no corresponding row (indicating it is a deleted line).

• $final_matchesarray

  Associative array of final matches. Index == row number of $final, value == corresponding row number of that same line in $orig or 'x' if there is no corresponding row (indicating it is a new line).

• $orig_rowsarray

  Associative array of interleaved rows of $orig with blanks to keep matches aligned with side-by-side diff of $final. A value >= 0 corresponds to index of $orig. Value < 0 indicates a blank row.

• $final_rowsarray

  Associative array of interleaved rows of $final with blanks to keep matches aligned with side-by-side diff of $orig. A value >= 0 corresponds to index of $final. Value < 0 indicates a blank row.

Performance profile

How much work a call to WP_Text_Diff_Renderer_Table::interleave_changed_lines() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

44–51

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 175.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

1

1 place in core call this, so the cost is paid more often than your own code shows.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Text_Diff_Renderer_Table::interleave_changed_lines() can have, taken from its control-flow graph on PHP 8.5.

Uses · 1

• WP_Text_Diff_Renderer_Table::compute_string_distance()Computes a number that is intended to reflect the "distance" between two strings.

Used by · 1

• WP_Text_Diff_Renderer_Table::_changed()Process changed lines to do word-by-word diffs for extra highlighting.

Source code

View on Trac ↗View on GitHub ↗

400	public function interleave_changed_lines( $orig, $final ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.finalFound401 402		// Contains all pairwise string comparisons. Keys are such that this need only be a one dimensional array.403		$matches = array();404		foreach ( array_keys( $orig ) as $o ) {405			foreach ( array_keys( $final ) as $f ) {406				$matches[ "$o,$f" ] = $this->compute_string_distance( $orig[ $o ], $final[ $f ] );407			}408		}409		asort( $matches ); // Order by string distance.410 411		$orig_matches  = array();412		$final_matches = array();413 414		foreach ( $matches as $keys => $difference ) {415			list($o, $f) = explode( ',', $keys );416			$o           = (int) $o;417			$f           = (int) $f;418 419			// Already have better matches for these guys.420			if ( isset( $orig_matches[ $o ] ) && isset( $final_matches[ $f ] ) ) {421				continue;422			}423 424			// First match for these guys. Must be best match.425			if ( ! isset( $orig_matches[ $o ] ) && ! isset( $final_matches[ $f ] ) ) {426				$orig_matches[ $o ]  = $f;427				$final_matches[ $f ] = $o;428				continue;429			}430 431			// Best match of this final is already taken? Must mean this final is a new row.432			if ( isset( $orig_matches[ $o ] ) ) {433				$final_matches[ $f ] = 'x';434			} elseif ( isset( $final_matches[ $f ] ) ) {435				// Best match of this orig is already taken? Must mean this orig is a deleted row.436				$orig_matches[ $o ] = 'x';437			}438		}439 440		// We read the text in this order.441		ksort( $orig_matches );442		ksort( $final_matches );443 444		// Stores rows and blanks for each column.445		$orig_rows      = array_keys( $orig_matches );446		$orig_rows_copy = $orig_rows;447		$final_rows     = array_keys( $final_matches );448 449		/*450		 * Interleaves rows with blanks to keep matches aligned.451		 * We may end up with some extraneous blank rows, but we'll just ignore them later.452		 */453		foreach ( $orig_rows_copy as $orig_row ) {454			$final_pos = array_search( $orig_matches[ $orig_row ], $final_rows, true );455			$orig_pos  = (int) array_search( $orig_row, $orig_rows, true );456 457			if ( false === $final_pos ) { // This orig is paired with a blank final.458				array_splice( $final_rows, $orig_pos, 0, -1 );459			} elseif ( $final_pos < $orig_pos ) { // This orig's match is up a ways. Pad final with blank rows.460				$diff_array = range( -1, $final_pos - $orig_pos );461				array_splice( $final_rows, $orig_pos, 0, $diff_array );462			} elseif ( $final_pos > $orig_pos ) { // This orig's match is down a ways. Pad orig with blank rows.463				$diff_array = range( -1, $orig_pos - $final_pos );464				array_splice( $orig_rows, $orig_pos, 0, $diff_array );465			}466		}467 468		// Pad the ends with blank rows if the columns aren't the same length.469		$diff_count = count( $orig_rows ) - count( $final_rows );470		if ( $diff_count < 0 ) {471			while ( $diff_count < 0 ) {472				array_push( $orig_rows, $diff_count++ );473			}474		} elseif ( $diff_count > 0 ) {475			$diff_count = -1 * $diff_count;476			while ( $diff_count < 0 ) {477				array_push( $final_rows, $diff_count++ );478			}479		}

Changelog

Introduced in 2.6.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

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Generated from the wordpress-develop 7.0.4 tag, from src/wp-includes/class-wp-text-diff-renderer-table.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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