source: trip-planner-front/node_modules/webpack-sources/lib/applySourceMap.js@ bdd6491

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
        Author Tobias Koppers @sokra
*/

"use strict";

var SourceNode = require("source-map").SourceNode;
var SourceMapConsumer = require("source-map").SourceMapConsumer;

var applySourceMap = function(
        sourceNode,
        sourceMapConsumer,
        sourceFile,
        removeGeneratedCodeForSourceFile
) {
        // The following notations are used to name stuff:
        // Left <------------> Middle <-------------------> Right
        // Input arguments:
        //        sourceNode                                       - Code mapping from Left to Middle
        //                   sourceFile                            - Name of a Middle file
        //                              sourceMapConsumer          - Code mapping from Middle to Right
        // Variables:
        //           l2m                      m2r
        // Left <-----------------------------------------> Right
        // Variables:
        //                       l2r

        var l2rResult = new SourceNode();
        var l2rOutput = [];

        var middleSourceContents = {};

        var m2rMappingsByLine = {};

        var rightSourceContentsSet = {};
        var rightSourceContentsLines = {};

        // Store all mappings by generated line
        sourceMapConsumer.eachMapping(
                function(mapping) {
                        (m2rMappingsByLine[mapping.generatedLine] =
                                m2rMappingsByLine[mapping.generatedLine] || []).push(mapping);
                },
                null,
                SourceMapConsumer.GENERATED_ORDER
        );

        // Store all source contents
        sourceNode.walkSourceContents(function(source, content) {
                middleSourceContents["$" + source] = content;
        });

        var middleSource = middleSourceContents["$" + sourceFile];
        var middleSourceLines = middleSource ? middleSource.split("\n") : undefined;

        // Walk all left to middle mappings
        sourceNode.walk(function(chunk, middleMapping) {
                var source;

                // Find a mapping from middle to right
                if(
                        middleMapping.source === sourceFile &&
                        middleMapping.line &&
                        m2rMappingsByLine[middleMapping.line]
                ) {
                        var m2rBestFit;
                        var m2rMappings = m2rMappingsByLine[middleMapping.line];
                        // Note: if this becomes a performance problem, use binary search
                        for(var i = 0; i < m2rMappings.length; i++) {
                                if(m2rMappings[i].generatedColumn <= middleMapping.column) {
                                        m2rBestFit = m2rMappings[i];
                                }
                        }
                        if(m2rBestFit) {
                                var allowMiddleName = false;
                                var middleLine;
                                var rightSourceContent;
                                var rightSourceContentLines;
                                var rightSource = m2rBestFit.source;
                                // Check if we have middle and right source for this mapping
                                // Then we could have an "identify" mapping
                                if(
                                        middleSourceLines &&
                                        rightSource &&
                                        (middleLine = middleSourceLines[m2rBestFit.generatedLine - 1]) &&
                                        ((rightSourceContentLines = rightSourceContentsLines[rightSource]) ||
                                                (rightSourceContent = sourceMapConsumer.sourceContentFor(
                                                        rightSource,
                                                        true
                                                )))
                                ) {
                                        if(!rightSourceContentLines) {
                                                rightSourceContentLines = rightSourceContentsLines[
                                                        rightSource
                                                ] = rightSourceContent.split("\n");
                                        }
                                        var rightLine = rightSourceContentLines[m2rBestFit.originalLine - 1];
                                        if(rightLine) {
                                                var offset = middleMapping.column - m2rBestFit.generatedColumn;
                                                if(offset > 0) {
                                                        var middlePart = middleLine.slice(
                                                                m2rBestFit.generatedColumn,
                                                                middleMapping.column
                                                        );
                                                        var rightPart = rightLine.slice(
                                                                m2rBestFit.originalColumn,
                                                                m2rBestFit.originalColumn + offset
                                                        );
                                                        if(middlePart === rightPart) {
                                                                // When original and generated code is equal we assume we have an "identity" mapping
                                                                // In this case we can offset the original position
                                                                m2rBestFit = Object.assign({}, m2rBestFit, {
                                                                        originalColumn: m2rBestFit.originalColumn + offset,
                                                                        generatedColumn: middleMapping.column
                                                                });
                                                        }
                                                }
                                                if(!m2rBestFit.name && middleMapping.name) {
                                                        allowMiddleName =
                                                                rightLine.slice(
                                                                        m2rBestFit.originalColumn,
                                                                        m2rBestFit.originalColumn + middleMapping.name.length
                                                                ) === middleMapping.name;
                                                }
                                        }
                                }

                                // Construct a left to right node from the found middle to right mapping
                                source = m2rBestFit.source;
                                l2rOutput.push(
                                        new SourceNode(
                                                m2rBestFit.originalLine,
                                                m2rBestFit.originalColumn,
                                                source,
                                                chunk,
                                                allowMiddleName ? middleMapping.name : m2rBestFit.name
                                        )
                                );

                                // Set the source contents once
                                if(!("$" + source in rightSourceContentsSet)) {
                                        rightSourceContentsSet["$" + source] = true;
                                        var sourceContent = sourceMapConsumer.sourceContentFor(source, true);
                                        if(sourceContent) {
                                                l2rResult.setSourceContent(source, sourceContent);
                                        }
                                }
                                return;
                        }
                }

                if((removeGeneratedCodeForSourceFile && middleMapping.source === sourceFile) || !middleMapping.source) {
                        // Construct a left to middle node with only generated code
                        // Because user do not want mappings to middle sources
                        // Or this chunk has no mapping
                        l2rOutput.push(chunk);
                        return;
                }

                // Construct a left to middle node
                source = middleMapping.source;
                l2rOutput.push(
                        new SourceNode(
                                middleMapping.line,
                                middleMapping.column,
                                source,
                                chunk,
                                middleMapping.name
                        )
                );
                if("$" + source in middleSourceContents) {
                        if(!("$" + source in rightSourceContentsSet)) {
                                l2rResult.setSourceContent(source, middleSourceContents["$" + source]);
                                delete middleSourceContents["$" + source];
                        }
                }
        });

        // Put output into the resulting SourceNode
        l2rResult.add(l2rOutput);
        return l2rResult;
};

module.exports = applySourceMap;