add some implementation stuff

Author: michaelficarra

.gitignore

@@ -0,0 +1,3 @@
+/tsconfig.tsbuildinfo
+/lib
+/node_modules

package-lock.json

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+{
+  "private": true,
+  "name": "proposal-concurrency-control",
+  "version": "1.0.0",
+  "description": "",
+  "main": "lib/index.js",
+  "type": "module",
+  "scripts": {
+    "build": "tsc",
+    "test": "node --test"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+ssh://git@github.com/michaelficarra/proposal-concurrency-control.git"
+  },
+  "author": "Michael Ficarra",
+  "bugs": {
+    "url": "https://github.com/michaelficarra/proposal-concurrency-control/issues"
+  },
+  "homepage": "https://github.com/michaelficarra/proposal-concurrency-control#readme",
+  "devDependencies": {
+    "typescript": "5.5.3"
+  },
+  "dependencies": {
+  }
+}

package.json

@@ -0,0 +1,16 @@
+
+import { Governor, Semaphore } from "./index.js";
+
+Object.defineProperty(globalThis, "Governor", {
+  configurable: true,
+  writable: true,
+  enumerable: false,
+  value: Governor,
+});
+
+Object.defineProperty(globalThis, "Semaphore", {
+  configurable: true,
+  writable: true,
+  enumerable: false,
+  value: Semaphore,
+});

src/auto.ts

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+export abstract class Governor {
+  abstract acquire(): Promise<GovernorToken>;
+
+  with<R>(fn: (...args: []) => R): Promise<Awaited<R>> {
+    return this.wrap(fn)();
+  }
+
+  wrap<T, A extends unknown[], R>(fn: (this: T, ...args: A) => R): ((this: T, ...args: A) => Promise<Awaited<R>>) {
+    const _this = this;
+    return async function(...args): Promise<Awaited<R>> {
+      const token = await _this.acquire();
+      try {
+        return await fn.apply(this, args);
+      } finally {
+        token[Symbol.dispose]();
+      }
+    };
+  }
+
+  wrapIterator<T>(iter: Iterator<T> | AsyncIterator<T>): AsyncIterator<T> {
+    const _this = this;
+    return {
+      next: async function(n) {
+        return await _this.wrap(iter.next as Iterator<T>['next']).call(iter, n);
+      },
+      return: async () =>
+        typeof iter.return === "function"
+          ? iter.return()
+          : { done: true, value: undefined }
+    }
+  }
+
+  // wrapIterable<T>(iter: Iterable<T> | AsyncIterable<T>): AsyncIterable<T> {
+  // }
+}
+
+export interface GovernorToken {
+  release(): void;
+  [Symbol.dispose](): void;
+}

src/governor.ts

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+export { Governor } from "./governor.js";
+export { Semaphore } from "./semaphore.js";
+export type { GovernorToken } from "./governor.ts";

src/index.ts

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+import { Governor } from "./governor.js";
+
+export class Semaphore extends Governor {
+  #limit: number;
+  #acquired: number = 0;
+  #wait: PromiseWithResolvers<void> | null = null;
+  #idleListeners: (() => void)[] = [];
+
+  constructor(limit: number) {
+    if ((limit >>> 0) !== limit) {
+      throw new TypeError("Limit must be an integer");
+    }
+    if (limit < 0) {
+      throw new RangeError("Limit must be non-negative");
+    }
+    super();
+
+    this.#limit = limit;
+  }
+
+  async acquire() {
+    while (this.#acquired >= this.#limit) {
+      if (!this.#wait) {
+        this.#wait = Promise.withResolvers<void>();
+      }
+      await this.#wait.promise;
+    }
+    ++this.#acquired;
+
+    let hasReleased = false;
+
+    const dispose = () => {
+      if (hasReleased) {
+        throw new Error("Already released");
+      }
+      hasReleased = true;
+      --this.#acquired;
+      if (this.#wait) {
+        this.#wait.resolve();
+        this.#wait = null;
+      } else if (this.#acquired === 0) {
+        this.#notifyIdleListeners();
+      }
+    };
+
+    return {
+      release: dispose,
+      [Symbol.dispose]: dispose,
+    };
+  }
+
+  addIdleListener(cb: () => void) {
+    this.#idleListeners.push(cb);
+  }
+
+  removeIdleListener(cb: () => void) {
+    const idx = this.#idleListeners.indexOf(cb);
+    if (idx >= 0) {
+      this.#idleListeners.splice(idx, 1);
+    }
+  }
+
+  #notifyIdleListeners() {
+    for (const cb of this.#idleListeners) {
+      try {
+        cb();
+      } catch {}
+    }
+  }
+}

src/semaphore.ts

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+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig to read more about this file */
+
+    /* Projects */
+    "incremental": true,                                 /* Save .tsbuildinfo files to allow for incremental compilation of projects. */
+    // "composite": true,                                /* Enable constraints that allow a TypeScript project to be used with project references. */
+    // "tsBuildInfoFile": "./.tsbuildinfo",              /* Specify the path to .tsbuildinfo incremental compilation file. */
+    // "disableSourceOfProjectReferenceRedirect": true,  /* Disable preferring source files instead of declaration files when referencing composite projects. */
+    // "disableSolutionSearching": true,                 /* Opt a project out of multi-project reference checking when editing. */
+    // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
+
+    /* Language and Environment */
+    "target": "esnext",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
+    // "jsx": "preserve",                                /* Specify what JSX code is generated. */
+    // "experimentalDecorators": true,                   /* Enable experimental support for legacy experimental decorators. */
+    // "emitDecoratorMetadata": true,                    /* Emit design-type metadata for decorated declarations in source files. */
+    // "jsxFactory": "",                                 /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h'. */
+    // "jsxFragmentFactory": "",                         /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
+    // "jsxImportSource": "",                            /* Specify module specifier used to import the JSX factory functions when using 'jsx: react-jsx*'. */
+    // "reactNamespace": "",                             /* Specify the object invoked for 'createElement'. This only applies when targeting 'react' JSX emit. */
+    // "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
+    // "useDefineForClassFields": true,                  /* Emit ECMAScript-standard-compliant class fields. */
+    // "moduleDetection": "auto",                        /* Control what method is used to detect module-format JS files. */
+
+    /* Modules */
+    "module": "esnext",                                  /* Specify what module code is generated. */
+    "rootDir": "src",                                    /* Specify the root folder within your source files. */
+    // "moduleResolution": "node10",                     /* Specify how TypeScript looks up a file from a given module specifier. */
+    // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
+    // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
+    // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
+    // "typeRoots": [],                                  /* Specify multiple folders that act like './node_modules/@types'. */
+    // "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
+    // "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
+    // "moduleSuffixes": [],                             /* List of file name suffixes to search when resolving a module. */
+    // "allowImportingTsExtensions": true,               /* Allow imports to include TypeScript file extensions. Requires '--moduleResolution bundler' and either '--noEmit' or '--emitDeclarationOnly' to be set. */
+    // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
+    // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
+    // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "resolveJsonModule": true,                        /* Enable importing .json files. */
+    // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
+    // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */
+
+    /* JavaScript Support */
+    // "allowJs": true,                                  /* Allow JavaScript files to be a part of your program. Use the 'checkJS' option to get errors from these files. */
+    // "checkJs": true,                                  /* Enable error reporting in type-checked JavaScript files. */
+    // "maxNodeModuleJsDepth": 1,                        /* Specify the maximum folder depth used for checking JavaScript files from 'node_modules'. Only applicable with 'allowJs'. */
+
+    /* Emit */
+    "declaration": true,                                 /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
+    // "declarationMap": true,                           /* Create sourcemaps for d.ts files. */
+    // "emitDeclarationOnly": true,                      /* Only output d.ts files and not JavaScript files. */
+    // "sourceMap": true,                                /* Create source map files for emitted JavaScript files. */
+    "inlineSourceMap": true,                             /* Include sourcemap files inside the emitted JavaScript. */
+    // "outFile": "./",                                  /* Specify a file that bundles all outputs into one JavaScript file. If 'declaration' is true, also designates a file that bundles all .d.ts output. */
+    "outDir": "lib",                                     /* Specify an output folder for all emitted files. */
+    "removeComments": true,                              /* Disable emitting comments. */
+    // "noEmit": true,                                   /* Disable emitting files from a compilation. */
+    // "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
+    // "importsNotUsedAsValues": "remove",               /* Specify emit/checking behavior for imports that are only used for types. */
+    // "downlevelIteration": true,                       /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
+    // "sourceRoot": "",                                 /* Specify the root path for debuggers to find the reference source code. */
+    // "mapRoot": "",                                    /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSources": true,                            /* Include source code in the sourcemaps inside the emitted JavaScript. */
+    "emitBOM": false,                                    /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
+    "newLine": "lf",                                     /* Set the newline character for emitting files. */
+    // "stripInternal": true,                            /* Disable emitting declarations that have '@internal' in their JSDoc comments. */
+    // "noEmitHelpers": true,                            /* Disable generating custom helper functions like '__extends' in compiled output. */
+    // "noEmitOnError": true,                            /* Disable emitting files if any type checking errors are reported. */
+    // "preserveConstEnums": true,                       /* Disable erasing 'const enum' declarations in generated code. */
+    // "declarationDir": "./",                           /* Specify the output directory for generated declaration files. */
+    // "preserveValueImports": true,                     /* Preserve unused imported values in the JavaScript output that would otherwise be removed. */
+
+    /* Interop Constraints */
+    // "isolatedModules": true,                          /* Ensure that each file can be safely transpiled without relying on other imports. */
+    // "verbatimModuleSyntax": true,                     /* Do not transform or elide any imports or exports not marked as type-only, ensuring they are written in the output file's format based on the 'module' setting. */
+    // "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
+    "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
+    "preserveSymlinks": true,                            /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
+    "forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */
+
+    /* Type Checking */
+    "strict": true,                                      /* Enable all strict type-checking options. */
+    "noImplicitAny": true,                               /* Enable error reporting for expressions and declarations with an implied 'any' type. */
+    "strictNullChecks": true,                            /* When type checking, take into account 'null' and 'undefined'. */
+    "strictFunctionTypes": true,                         /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
+    "strictBindCallApply": true,                         /* Check that the arguments for 'bind', 'call', and 'apply' methods match the original function. */
+    "strictPropertyInitialization": true,                /* Check for class properties that are declared but not set in the constructor. */
+    "noImplicitThis": true,                              /* Enable error reporting when 'this' is given the type 'any'. */
+    "useUnknownInCatchVariables": true,                  /* Default catch clause variables as 'unknown' instead of 'any'. */
+    "alwaysStrict": true,                                /* Ensure 'use strict' is always emitted. */
+    "noUnusedLocals": true,                              /* Enable error reporting when local variables aren't read. */
+    "noUnusedParameters": true,                          /* Raise an error when a function parameter isn't read. */
+    "exactOptionalPropertyTypes": true,                  /* Interpret optional property types as written, rather than adding 'undefined'. */
+    "noImplicitReturns": true,                           /* Enable error reporting for codepaths that do not explicitly return in a function. */
+    "noFallthroughCasesInSwitch": true,                  /* Enable error reporting for fallthrough cases in switch statements. */
+    "noUncheckedIndexedAccess": true,                    /* Add 'undefined' to a type when accessed using an index. */
+    "noImplicitOverride": true,                          /* Ensure overriding members in derived classes are marked with an override modifier. */
+    "noPropertyAccessFromIndexSignature": true,          /* Enforces using indexed accessors for keys declared using an indexed type. */
+    // "allowUnusedLabels": true,                        /* Disable error reporting for unused labels. */
+    // "allowUnreachableCode": true,                     /* Disable error reporting for unreachable code. */
+
+    /* Completeness */
+    // "skipDefaultLibCheck": true,                      /* Skip type checking .d.ts files that are included with TypeScript. */
+    "skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
+  }
+}