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Merge pull request #23 from brentwilton/single-pass-replacesource-node
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Single pass ReplaceSource .node performance improvement
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@sokra
sokra authored Aug 29, 2018
2 parents b643bfb + cf11460 commit b141232
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Showing 2 changed files with 261 additions and 60 deletions.
240 changes: 180 additions & 60 deletions lib/ReplaceSource.js
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Original file line number Diff line number Diff line change
Expand Up @@ -71,30 +71,60 @@ class ReplaceSource extends Source {
}

node(options) {
this._sortReplacements();
var result = [this._source.node(options)];
this.replacements.forEach(function(repl) {
var remSource = result.pop();
var splitted1 = this._splitSourceNode(remSource, Math.floor(repl[1] + 1));
var splitted2;
if(Array.isArray(splitted1)) {
splitted2 = this._splitSourceNode(splitted1[0], Math.floor(repl[0]));
if(Array.isArray(splitted2)) {
result.push(splitted1[1], this._replacementToSourceNode(splitted2[1], repl[2]), splitted2[0]);
} else {
result.push(splitted1[1], this._replacementToSourceNode(splitted1[1], repl[2]), splitted1[0]);
}
} else {
splitted2 = this._splitSourceNode(remSource, Math.floor(repl[0]));
if(Array.isArray(splitted2)) {
result.push(this._replacementToSourceNode(splitted2[1], repl[2]), splitted2[0]);
} else {
result.push(repl[2], remSource);
}
var node = this._source.node(options);
if(this.replacements.length === 0) {
return node;
}
this.replacements.sort(sortReplacementsAscending);
var replace = new ReplacementEnumerator(this.replacements);
var output = [];
var position = 0;
var sources = Object.create(null);
var sourcesInLines = Object.create(null);

// We build a new list of SourceNodes in "output"
// from the original mapping data

var result = new SourceNode();

// We need to add source contents manually
// because "walk" will not handle it
node.walkSourceContents(function(sourceFile, sourceContent) {
result.setSourceContent(sourceFile, sourceContent);
sources["$" + sourceFile] = sourceContent;
});

var replaceInStringNode = this._replaceInStringNode.bind(this, output, replace, function getOriginalSource(mapping) {
var key = "$" + mapping.source;
var lines = sourcesInLines[key];
if(!lines) {
var source = sources[key];
if(!source) return null;
lines = source.split("\n").map(function(line) {
return line + "\n";
});
sourcesInLines[key] = lines;
}
}, this);
result = result.reverse();
return new SourceNode(null, null, null, result);
// line is 1-based
if(mapping.line > lines.length) return null;
var line = lines[mapping.line - 1];
return line.substr(mapping.column);
});

node.walk(function(chunk, mapping) {
position = replaceInStringNode(chunk, position, mapping);
});

// If any replacements occur after the end of the original file, then we append them
// directly to the end of the output
var remaining = replace.footer();
if(remaining) {
output.push(remaining);
}

result.add(output);

return result;
}

listMap(options) {
Expand Down Expand Up @@ -149,52 +179,142 @@ class ReplaceSource extends Source {
return map;
}

_replacementToSourceNode(oldNode, newString) {
var map = oldNode.toStringWithSourceMap({
file: "?"
}).map;
var original = new SourceMapConsumer(map.toJSON()).originalPositionFor({
line: 1,
column: 0
});
if(original) {
return new SourceNode(original.line, original.column, original.source, newString);
} else {
return newString;
}
_splitString(str, position) {
return position <= 0 ? ["", str] : [str.substr(0, position), str.substr(position)];
}

_splitSourceNode(node, position) {
if(typeof node === "string") {
if(node.length <= position) return position - node.length;
return position <= 0 ? ["", node] : [node.substr(0, position), node.substr(position)];
} else {
for(var i = 0; i < node.children.length; i++) {
position = this._splitSourceNode(node.children[i], position);
if(Array.isArray(position)) {
var leftNode = new SourceNode(
node.line,
node.column,
node.source,
node.children.slice(0, i).concat([position[0]]),
node.name
_replaceInStringNode(output, replace, getOriginalSource, node, position, mapping) {
var original = undefined;

do {
var splitPosition = replace.position - position;
// If multiple replaces occur in the same location then the splitPosition may be
// before the current position for the subsequent splits. Ensure it is >= 0
if(splitPosition < 0) {
splitPosition = 0;
}
if(splitPosition >= node.length || replace.done) {
if(replace.emit) {
var nodeEnd = new SourceNode(
mapping.line,
mapping.column,
mapping.source,
node,
mapping.name
);
var rightNode = new SourceNode(
node.line,
node.column,
node.source, [position[1]].concat(node.children.slice(i + 1)),
node.name
output.push(nodeEnd);
}
return position + node.length;
}

var originalColumn = mapping.column;

// Try to figure out if generated code matches original code of this segement
// If this is the case we assume that it's allowed to move mapping.column
// Because getOriginalSource can be expensive we only do it when neccessary

var nodePart;
if(splitPosition > 0) {
nodePart = node.slice(0, splitPosition);
if(original === undefined) {
original = getOriginalSource(mapping);
}
if(original && original.length >= splitPosition && original.startsWith(nodePart)) {
mapping.column += splitPosition;
original = original.substr(splitPosition);
}
}

var emit = replace.next();
if(!emit) {
// Stop emitting when we have found the beginning of the string to replace.
// Emit the part of the string before splitPosition
if(splitPosition > 0) {
var nodeStart = new SourceNode(
mapping.line,
originalColumn,
mapping.source,
nodePart,
mapping.name
);
leftNode.sourceContents = node.sourceContents;
return [leftNode, rightNode];
output.push(nodeStart);
}

// Emit the replacement value
if(replace.value) {
output.push(new SourceNode(
mapping.line,
mapping.column,
mapping.source,
replace.value
));
}
}

// Recurse with remainder of the string as there may be multiple replaces within a single node
node = node.substr(splitPosition);
position += splitPosition;
} while (true);
}
}

function sortReplacementsAscending(a, b) {
var diff = a[1] - b[1]; // end
if(diff !== 0)
return diff;
diff = a[0] - b[0]; // start
if(diff !== 0)
return diff;
return a[3] - b[3]; // insert order
}

class ReplacementEnumerator {
constructor(replacements) {
this.emit = true;
this.done = !replacements || replacements.length === 0;
this.index = 0;
this.replacements = replacements;
if(!this.done) {
// Set initial start position in case .header is not called
var repl = replacements[0];
this.position = Math.floor(repl[0]);
if(this.position < 0)
this.position = 0;
}
}

next() {
if(this.done)
return true;
if(this.emit) {
// Start point found. stop emitting. set position to find end
var repl = this.replacements[this.index];
var end = Math.floor(repl[1] + 1);
this.position = end;
this.value = repl[2];
} else {
// End point found. start emitting. set position to find next start
this.index++;
if(this.index >= this.replacements.length) {
this.done = true;
} else {
var nextRepl = this.replacements[this.index];
var start = Math.floor(nextRepl[0]);
this.position = start;
}
return position;
}
if(this.position < 0)
this.position = 0;
this.emit = !this.emit;
return this.emit;
}

_splitString(str, position) {
return position <= 0 ? ["", str] : [str.substr(0, position), str.substr(position)];
footer() {
if(!this.done && !this.emit)
this.next(); // If we finished _replaceInNode mid emit we advance to next entry
return this.done ? [] : this.replacements.slice(this.index).map(function(repl) {
return repl[2];
}).join("");
}
}

Expand Down
81 changes: 81 additions & 0 deletions test/ReplaceSource.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ describe("ReplaceSource", function() {
resultListMap.map.version.should.be.eql(resultMap.map.version);
resultListMap.map.sources.should.be.eql(resultMap.map.sources);
resultListMap.map.sourcesContent.should.be.eql(resultMap.map.sourcesContent);
resultMap.map.mappings.should.be.eql("AAAA,CAAC,EAAI,KAAE,IAAC;AACR,CAAC;AAAA;AAAA;AAID,IAAI,CACJ");
resultListMap.map.mappings.should.be.eql("AAAA;AACA;AAAA;AAAA;AAIA,KACA");
});

Expand All @@ -64,13 +65,93 @@ describe("ReplaceSource", function() {
var resultListMap = source.sourceAndMap({
columns: false
});

resultText.should.be.eql("Message: Hey Ad!");
resultMap.source.should.be.eql(resultText);
resultListMap.source.should.be.eql(resultText);
resultListMap.map.file.should.be.eql(resultMap.map.file);
resultListMap.map.version.should.be.eql(resultMap.map.version);
resultListMap.map.sources.should.be.eql(resultMap.map.sources);
resultListMap.map.sourcesContent.should.be.eql(resultMap.map.sourcesContent);
resultMap.map.mappings.should.be.eql("AAAA,WAAE,GACE");
resultListMap.map.mappings.should.be.eql("AAAA,cACA");
});

it("should prepend items correctly", function() {
var source = new ReplaceSource(
new OriginalSource("Line 1", "file.txt")
);
source.insert(-1, "Line -1\n");
source.insert(-1, "Line 0\n");
var resultText = source.source();
var resultMap = source.sourceAndMap({
columns: true
});
var resultListMap = source.sourceAndMap({
columns: false
});

resultText.should.be.eql("Line -1\nLine 0\nLine 1");
resultMap.source.should.be.eql(resultText);
resultListMap.source.should.be.eql(resultText);
resultListMap.map.file.should.be.eql(resultMap.map.file);
resultListMap.map.version.should.be.eql(resultMap.map.version);
resultListMap.map.sources.should.be.eql(resultMap.map.sources);
resultListMap.map.sourcesContent.should.be.eql(resultMap.map.sourcesContent);
resultMap.map.mappings.should.be.eql("AAAA;AAAA;AAAA");
resultListMap.map.mappings.should.be.eql("AAAA;AAAA;AAAA");
});

it("should prepend items with replace at start correctly", function() {
var source = new ReplaceSource(
new OriginalSource([
"Line 1",
"Line 2"
].join("\n"), "file.txt")
);
source.insert(-1, "Line 0\n");
source.replace(0, 5, "Hello");
var resultText = source.source();
var resultMap = source.sourceAndMap({
columns: true
});
var resultListMap = source.sourceAndMap({
columns: false
});

resultText.should.be.eql("Line 0\nHello\nLine 2");
resultMap.source.should.be.eql(resultText);
resultListMap.source.should.be.eql(resultText);
resultListMap.map.file.should.be.eql(resultMap.map.file);
resultListMap.map.version.should.be.eql(resultMap.map.version);
resultListMap.map.sources.should.be.eql(resultMap.map.sources);
resultListMap.map.sourcesContent.should.be.eql(resultMap.map.sourcesContent);
resultMap.map.mappings.should.be.eql("AAAA;AAAA,KAAM;AACN");
resultListMap.map.mappings.should.be.eql("AAAA;AAAA;AACA");
});

it("should append items correctly", function() {
var line1;
var source = new ReplaceSource(
new OriginalSource(line1 = "Line 1\n", "file.txt")
);
source.insert(line1.length + 1, "Line 2\n");
var resultText = source.source();
var resultMap = source.sourceAndMap({
columns: true
});
var resultListMap = source.sourceAndMap({
columns: false
});

resultText.should.be.eql("Line 1\nLine 2\n");
resultMap.source.should.be.eql(resultText);
resultListMap.source.should.be.eql(resultText);
resultListMap.map.file.should.be.eql(resultMap.map.file);
resultListMap.map.version.should.be.eql(resultMap.map.version);
resultListMap.map.sources.should.be.eql(resultMap.map.sources);
resultListMap.map.sourcesContent.should.be.eql(resultMap.map.sourcesContent);
resultMap.map.mappings.should.be.eql("AAAA");
resultListMap.map.mappings.should.be.eql("AAAA;;");
});
});

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