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Merged
mhegazy merged 5 commits into from
Apr 4, 2016
Merged

Avoid writing files that are not changed while compiling incrementally. #6937

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c7e80e1
Avoid writing files that are not changed while compiling incrementally.
Feb 6, 2016
63c6908
Create createHash and getModifiedTime under sys, and refactor impleme…
Feb 9, 2016
acf965a
Refine implementation
Feb 10, 2016
0282c04
Revert hash object caching
Feb 10, 2016
a481305
Reorganize related functions
Feb 11, 2016
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39 changes: 38 additions & 1 deletion src/compiler/program.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -559,6 +559,12 @@ namespace ts {
sourceMap: false,
};

interface OutputFingerprint {
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@DanielRosenwasser DanielRosenwasser Apr 3, 2016

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Mark this /* @internal */

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@vilicvane vilicvane Apr 4, 2016

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@DanielRosenwasser I am confused, it's not even exported, why does it need /** @internal */?

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@DanielRosenwasser DanielRosenwasser Apr 4, 2016

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Whoops! Misread the code, forgive me. I was taking a quick glance at this PR again since it's been a bit.

hash: string;
byteOrderMark: boolean;
mtime: Date;
}

export function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost {
const existingDirectories: Map<boolean> = {};

Expand Down Expand Up @@ -609,11 +615,42 @@ namespace ts {
}
}

const outputFingerprints: Map<OutputFingerprint> =
options.watch && sys.createHash && sys.getModifiedTime ? {} : undefined;

const fileWriter: typeof sys.writeFile = outputFingerprints ?
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@mhegazy mhegazy Feb 10, 2016

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why not just a function?

function writeFile(fileName, data, writeByteOrderMark) {
    if (outputFingerprints) {
        const hash = sys.createHash(data);
        const mtimeBefore = sys.getModifiedTime(fileName);

        if (mtimeBefore && hasProperty(outputFingerprints, fileName)) {
            const fingerprint = outputFingerprints[fileName];

            // If output has not been changed, and the file has no external modification
            if (fingerprint.byteOrderMark === writeByteOrderMark &&
                fingerprint.hash === hash &&
                fingerprint.mtime.getTime() === mtimeBefore.getTime()) {
                return;
            }
        }
    }

    sys.writeFile(fileName, data, writeByteOrderMark);

    if (outputFingerprints) {
        const mtimeAfter = sys.getModifiedTime(fileName);

        outputFingerprints[fileName] = {
            hash,
            byteOrderMark: writeByteOrderMark,
            mtime: mtimeAfter
        };
    }
}

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@vilicvane vilicvane Feb 10, 2016

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@mhegazy I personally do not like parallel branches with same condition (because they can not indicate a strong relationship between those branches), so if I write them into a single function, I would like a single if...else with two sys.writeFile in each branch. And after merging them together, function fileWriter would be awkward to exist alone with writeFile. If I inline fileWriter into writeFile, it would result in a long try block. 😢 What's your suggestion?

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@mhegazy mhegazy Feb 10, 2016

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what about two functions then:

const outputFingerprints: Map<OutputFingerprint>;


function writeFile(fileName, data, writeByteOrderMark) {
    if (options.watch && sys.createHash && sys.getModifiedTime) {
        writeFileIfUpdated(fileName, data, writeByteOrderMark);
    }
    else {
        sys.writeFile(fileName, data, writeByteOrderMark);
    }
}

function writeFileIfUpdated(fileName, data, writeByteOrderMark) {
    if (!outputFingerprints) {
        outputFingerprints = {};
    }

    const hash = sys.createHash(data);
    const mtimeBefore = sys.getModifiedTime(fileName);

    if (mtimeBefore && hasProperty(outputFingerprints, fileName)) {
        const fingerprint = outputFingerprints[fileName];

        // If output has not been changed, and the file has no external modification
        if (fingerprint.byteOrderMark === writeByteOrderMark &&
            fingerprint.hash === hash &&
            fingerprint.mtime.getTime() === mtimeBefore.getTime()) {
            return;
        }

        sys.writeFile(fileName, data, writeByteOrderMark);

        const mtimeAfter = sys.getModifiedTime(fileName);

        outputFingerprints[fileName] = {
            hash,
            byteOrderMark: writeByteOrderMark,
            mtime: mtimeAfter
        };
    }
}

(fileName, data, writeByteOrderMark) => {
const hash = sys.createHash(data);
const mtimeBefore = sys.getModifiedTime(fileName);

if (mtimeBefore && outputFingerprints.hasOwnProperty(fileName)) {
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@DanielRosenwasser DanielRosenwasser Feb 9, 2016

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Use the hasProperty function

const fingerprint = outputFingerprints[fileName];

// If output has not been changed, and the file has no external modification
if (fingerprint.byteOrderMark === writeByteOrderMark &&
fingerprint.hash === hash &&
fingerprint.mtime.getTime() === mtimeBefore.getTime()) {
return;
}
}

sys.writeFile(fileName, data, writeByteOrderMark);

const mtimeAfter = sys.getModifiedTime(fileName);

outputFingerprints[fileName] = {
hash,
byteOrderMark: writeByteOrderMark,
mtime: mtimeAfter
};
} :
(fileName, data, writeByteOrderMark) => sys.writeFile(fileName, data, writeByteOrderMark);

function writeFile(fileName: string, data: string, writeByteOrderMark: boolean, onError?: (message: string) => void) {
try {
const start = new Date().getTime();
ensureDirectoriesExist(getDirectoryPath(normalizePath(fileName)));
sys.writeFile(fileName, data, writeByteOrderMark);
fileWriter(fileName, data, writeByteOrderMark);
ioWriteTime += new Date().getTime() - start;
}
catch (e) {
Expand Down
11 changes: 11 additions & 0 deletions src/compiler/sys.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,8 @@ namespace ts {
getExecutingFilePath(): string;
getCurrentDirectory(): string;
readDirectory(path: string, extension?: string, exclude?: string[]): string[];
getModifiedTime?(path: string): Date;
createHash?(data: string): string;
getMemoryUsage?(): number;
exit(exitCode?: number): void;
}
Expand Down Expand Up @@ -226,6 +228,7 @@ namespace ts {
const _fs = require("fs");
const _path = require("path");
const _os = require("os");
const _crypto = require("crypto");

// average async stat takes about 30 microseconds
// set chunk size to do 30 files in < 1 millisecond
Expand Down Expand Up @@ -556,6 +559,14 @@ namespace ts {
return process.cwd();
},
readDirectory,
getModifiedTime(path) {
return _fs.existsSync(path) && _fs.statSync(path).mtime;
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@DanielRosenwasser DanielRosenwasser Feb 9, 2016

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I this should be

let stat: any;
try {
    stat = _fs.statSync(path);
}
catch (e) {
    return undefined;
}

return stat.mtime;

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@vilicvane vilicvane Feb 10, 2016

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@DanielRosenwasser Can I put .mtime into try block and return it directly?

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@DanielRosenwasser DanielRosenwasser Feb 10, 2016

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I considered this, but I was thinking that if for some reason statSync returned undefined, we'd want to know about it. Thinking about it now, I think it might be better to return undefined unless someone else has other thoughts.

},
createHash(data) {
const hash = _crypto.createHash("md5");
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@DanielRosenwasser DanielRosenwasser Feb 9, 2016

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Do we always want to use MD5 @mhegazy?

Also, could you get away with a single call to createHash?

if (!hash) {
    hash = _crypto.createHash("md5");
}

hash.update(data);
return hash.digest("hex");

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@vilicvane vilicvane Feb 10, 2016

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@DanielRosenwasser Seems that we need to createHash every time.

hash.update(data);
return hash.digest("hex");
},
getMemoryUsage() {
if (global.gc) {
global.gc();
Expand Down