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module: cache nearest parent package.json per directory #65326

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module: cache nearest parent package.json per directory #65326

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68 changes: 49 additions & 19 deletions lib/internal/modules/package_json_reader.js
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,8 @@ const {
ERR_MODULE_NOT_FOUND,
},
} = require('internal/errors');
const { kEmptyObject } = require('internal/util');
const { kEmptyObject, isWindows } = require('internal/util');
const permission = require('internal/process/permission');
const modulesBinding = internalBinding('modules');
const path = require('path');
const { validateString } = require('internal/validators');
Expand Down Expand Up @@ -140,10 +141,18 @@ function read(jsonPath, { base, specifier, isESM } = kEmptyObject) {
}

/**
* A cache mapping a module's path to its parent `package.json` file's path.
* This is used in concert with `deserializedPackageJSONCache` to improve
* the performance of `getNearestParentPackageJSON` when called repeatedly
* on the same module paths.
* A cache mapping a directory to the path of the nearest `package.json` at or
* above it (`null` when there is none). The native traversal for a module
* starts at the module's directory, so every module in a directory shares one
* entry and one native call. Used in concert with
* `deserializedPackageJSONCache`.
*/
const directoryToParentPackageJSONPathCache = new SafeMap();

/**
* When the permission model is enabled the native traversal also depends on
* the read permissions in effect at the time of the call, so results are only
* remembered per exact module path, as before.
*/
const moduleToParentPackageJSONCache = new SafeMap();

Expand All @@ -158,30 +167,51 @@ const moduleToParentPackageJSONCache = new SafeMap();
*/
const deserializedPackageJSONCache = new SafeMap();

/**
* The directory the native nearest-parent traversal starts from for `checkPath`
* (see BindingData::NormalizePath/TraverseParent): the path itself when it has
* a trailing separator, its dirname otherwise.
* @param {string} checkPath
* @returns {string}
*/
function getTraversalStartDirectory(checkPath) {
const last = checkPath[checkPath.length - 1];
if (last === '/' || (isWindows && last === '\\')) {
return StringPrototypeSlice(checkPath, 0, -1);
}
return path.dirname(checkPath);
}

/**
* Get the nearest parent package.json file from a given path.
* Return the package.json data and the path to the package.json file, or undefined.
* @param {string} checkPath The path to start searching from.
* @returns {undefined | DeserializedPackageConfig}
*/
function getNearestParentPackageJSON(checkPath) {
const parentPackageJSONPath = moduleToParentPackageJSONCache.get(checkPath);
if (parentPackageJSONPath !== undefined) {
return deserializedPackageJSONCache.get(parentPackageJSONPath);
const permissionEnabled = permission.isEnabled();
const cache = permissionEnabled ? moduleToParentPackageJSONCache : directoryToParentPackageJSONPathCache;
const key = permissionEnabled ? checkPath : getTraversalStartDirectory(checkPath);
let parentPackageJSONPath = cache.get(key);
if (parentPackageJSONPath === undefined) {
const result = modulesBinding.getNearestParentPackageJSON(checkPath);
if (result === undefined) {
parentPackageJSONPath = null;
} else {
const packageConfig = deserializePackageJSON(checkPath, result);
parentPackageJSONPath = packageConfig.path;
if (!deserializedPackageJSONCache.has(parentPackageJSONPath)) {
deserializedPackageJSONCache.set(parentPackageJSONPath, packageConfig);
}
}
cache.set(key, parentPackageJSONPath);
}

const result = modulesBinding.getNearestParentPackageJSON(checkPath);
const packageConfig = deserializePackageJSON(checkPath, result);

moduleToParentPackageJSONCache.set(checkPath, packageConfig.path);

const maybeCachedPackageConfig = deserializedPackageJSONCache.get(packageConfig.path);
if (maybeCachedPackageConfig !== undefined) {
return maybeCachedPackageConfig;
if (parentPackageJSONPath === null) {
// No package.json above this path: same shape as before, carrying the queried path.
return deserializePackageJSON(checkPath, undefined);
}

deserializedPackageJSONCache.set(packageConfig.path, packageConfig);
return packageConfig;
return deserializedPackageJSONCache.get(parentPackageJSONPath);
}

/**
Expand Down
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