116 lines
4.5 KiB
PHP
116 lines
4.5 KiB
PHP
<?php
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/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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namespace Microsoft\PhpParser;
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/**
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* FilePositionMap can be used to get the line number for a large number of nodes (starting from 1).
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* It works the most efficiently when the requested node is close to the previously requested node.
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*
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* Other designs that weren't chosen:
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* - Precomputing all of the start/end offsets when initializing was slower - Some offsets weren't needed, and walking the tree was slower.
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* - Caching line numbers for previously requested offsets wasn't really necessary, since offsets are usually close together and weren't requested repeatedly.
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*/
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class FilePositionMap {
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/** @var string the full file contents */
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private $fileContents;
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/** @var int - Precomputed strlen($file_contents) */
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private $fileContentsLength;
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/** @var int the 0-based byte offset of the most recent request for a line number. */
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private $currentOffset;
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/** @var int the 1-based line number for $this->currentOffset (updated whenever currentOffset is updated) */
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private $lineForCurrentOffset;
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public function __construct(string $file_contents) {
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$this->fileContents = $file_contents;
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$this->fileContentsLength = \strlen($file_contents);
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$this->currentOffset = 0;
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$this->lineForCurrentOffset = 1;
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}
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/**
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* @param Node|Token $node
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*/
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public function getStartLine($node) : int {
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return $this->getLineNumberForOffset($node->getStartPosition());
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}
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/**
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* @param Node|Token $node
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* Similar to getStartLine but includes the column
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*/
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public function getStartLineCharacterPositionForOffset($node) : LineCharacterPosition {
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return $this->getLineCharacterPositionForOffset($node->getStartPosition());
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}
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/** @param Node|Token $node */
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public function getEndLine($node) : int {
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return $this->getLineNumberForOffset($node->getEndPosition());
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}
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/**
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* @param Node|Token $node
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* Similar to getStartLine but includes the column
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*/
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public function getEndLineCharacterPosition($node) : LineCharacterPosition {
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return $this->getLineCharacterPositionForOffset($node->getEndPosition());
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}
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/**
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* @param int $offset
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* Similar to getStartLine but includes both the line and the column
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*/
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public function getLineCharacterPositionForOffset(int $offset) : LineCharacterPosition {
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$line = $this->getLineNumberForOffset($offset);
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$character = $this->getColumnForOffset($offset);
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return new LineCharacterPosition($line, $character);
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}
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/**
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* @param int $offset - A 0-based byte offset
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* @return int - gets the 1-based line number for $offset
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*/
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public function getLineNumberForOffset(int $offset) : int {
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if ($offset < 0) {
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$offset = 0;
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} elseif ($offset > $this->fileContentsLength) {
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$offset = $this->fileContentsLength;
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}
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$currentOffset = $this->currentOffset;
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if ($offset > $currentOffset) {
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$this->lineForCurrentOffset += \substr_count($this->fileContents, "\n", $currentOffset, $offset - $currentOffset);
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$this->currentOffset = $offset;
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} elseif ($offset < $currentOffset) {
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$this->lineForCurrentOffset -= \substr_count($this->fileContents, "\n", $offset, $currentOffset - $offset);
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$this->currentOffset = $offset;
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}
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return $this->lineForCurrentOffset;
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}
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/**
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* @param int $offset - A 0-based byte offset
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* @return int - gets the 1-based column number for $offset
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*/
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public function getColumnForOffset(int $offset) : int {
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$length = $this->fileContentsLength;
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if ($offset <= 1) {
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return 1;
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} elseif ($offset > $length) {
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$offset = $length;
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}
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// Postcondition: offset >= 1, ($lastNewlinePos < $offset)
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// If there was no previous newline, lastNewlinePos = 0
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// Start strrpos check from the character before the current character,
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// in case the current character is a newline.
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$lastNewlinePos = \strrpos($this->fileContents, "\n", -$length + $offset - 1);
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return 1 + $offset - ($lastNewlinePos === false ? 0 : $lastNewlinePos + 1);
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}
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}
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