马宇豪
2024-07-16 f591c27b57e2418c9495bc02ae8cfff84d35bc18
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/*
    MIT License http://www.opensource.org/licenses/mit-license.php
    Author Tobias Koppers @sokra
*/
 
"use strict";
 
const ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".split(
    ""
);
 
const CONTINUATION_BIT = 0x20;
 
const createMappingsSerializer = options => {
    const linesOnly = options && options.columns === false;
    return linesOnly
        ? createLinesOnlyMappingsSerializer()
        : createFullMappingsSerializer();
};
 
const createFullMappingsSerializer = () => {
    let currentLine = 1;
    let currentColumn = 0;
    let currentSourceIndex = 0;
    let currentOriginalLine = 1;
    let currentOriginalColumn = 0;
    let currentNameIndex = 0;
    let activeMapping = false;
    let activeName = false;
    let initial = true;
    return (
        generatedLine,
        generatedColumn,
        sourceIndex,
        originalLine,
        originalColumn,
        nameIndex
    ) => {
        if (activeMapping && currentLine === generatedLine) {
            // A mapping is still active
            if (
                sourceIndex === currentSourceIndex &&
                originalLine === currentOriginalLine &&
                originalColumn === currentOriginalColumn &&
                !activeName &&
                nameIndex < 0
            ) {
                // avoid repeating the same original mapping
                return "";
            }
        } else {
            // No mapping is active
            if (sourceIndex < 0) {
                // avoid writing unneccessary generated mappings
                return "";
            }
        }
 
        let str;
        if (currentLine < generatedLine) {
            str = ";".repeat(generatedLine - currentLine);
            currentLine = generatedLine;
            currentColumn = 0;
            initial = false;
        } else if (initial) {
            str = "";
            initial = false;
        } else {
            str = ",";
        }
 
        const writeValue = value => {
            const sign = (value >>> 31) & 1;
            const mask = value >> 31;
            const absValue = (value + mask) ^ mask;
            let data = (absValue << 1) | sign;
            for (;;) {
                const sextet = data & 0x1f;
                data >>= 5;
                if (data === 0) {
                    str += ALPHABET[sextet];
                    break;
                } else {
                    str += ALPHABET[sextet | CONTINUATION_BIT];
                }
            }
        };
        writeValue(generatedColumn - currentColumn);
        currentColumn = generatedColumn;
        if (sourceIndex >= 0) {
            activeMapping = true;
            if (sourceIndex === currentSourceIndex) {
                str += "A";
            } else {
                writeValue(sourceIndex - currentSourceIndex);
                currentSourceIndex = sourceIndex;
            }
            writeValue(originalLine - currentOriginalLine);
            currentOriginalLine = originalLine;
            if (originalColumn === currentOriginalColumn) {
                str += "A";
            } else {
                writeValue(originalColumn - currentOriginalColumn);
                currentOriginalColumn = originalColumn;
            }
            if (nameIndex >= 0) {
                writeValue(nameIndex - currentNameIndex);
                currentNameIndex = nameIndex;
                activeName = true;
            } else {
                activeName = false;
            }
        } else {
            activeMapping = false;
        }
        return str;
    };
};
 
const createLinesOnlyMappingsSerializer = () => {
    let lastWrittenLine = 0;
    let currentLine = 1;
    let currentSourceIndex = 0;
    let currentOriginalLine = 1;
    return (
        generatedLine,
        _generatedColumn,
        sourceIndex,
        originalLine,
        _originalColumn,
        _nameIndex
    ) => {
        if (sourceIndex < 0) {
            // avoid writing generated mappings at all
            return "";
        }
        if (lastWrittenLine === generatedLine) {
            // avoid writing multiple original mappings per line
            return "";
        }
        let str;
        const writeValue = value => {
            const sign = (value >>> 31) & 1;
            const mask = value >> 31;
            const absValue = (value + mask) ^ mask;
            let data = (absValue << 1) | sign;
            for (;;) {
                const sextet = data & 0x1f;
                data >>= 5;
                if (data === 0) {
                    str += ALPHABET[sextet];
                    break;
                } else {
                    str += ALPHABET[sextet | CONTINUATION_BIT];
                }
            }
        };
        lastWrittenLine = generatedLine;
        if (generatedLine === currentLine + 1) {
            currentLine = generatedLine;
            if (sourceIndex === currentSourceIndex) {
                currentSourceIndex = sourceIndex;
                if (originalLine === currentOriginalLine + 1) {
                    currentOriginalLine = originalLine;
                    return ";AACA";
                } else {
                    str = ";AA";
                    writeValue(originalLine - currentOriginalLine);
                    currentOriginalLine = originalLine;
                    return str + "A";
                }
            } else {
                str = ";A";
                writeValue(sourceIndex - currentSourceIndex);
                currentSourceIndex = sourceIndex;
                writeValue(originalLine - currentOriginalLine);
                currentOriginalLine = originalLine;
                return str + "A";
            }
        } else {
            str = ";".repeat(generatedLine - currentLine);
            currentLine = generatedLine;
            if (sourceIndex === currentSourceIndex) {
                currentSourceIndex = sourceIndex;
                if (originalLine === currentOriginalLine + 1) {
                    currentOriginalLine = originalLine;
                    return str + "AACA";
                } else {
                    str += "AA";
                    writeValue(originalLine - currentOriginalLine);
                    currentOriginalLine = originalLine;
                    return str + "A";
                }
            } else {
                str += "A";
                writeValue(sourceIndex - currentSourceIndex);
                currentSourceIndex = sourceIndex;
                writeValue(originalLine - currentOriginalLine);
                currentOriginalLine = originalLine;
                return str + "A";
            }
        }
    };
};
 
module.exports = createMappingsSerializer;