64 lines
2.4 KiB
JavaScript
Executable File
64 lines
2.4 KiB
JavaScript
Executable File
import path from '../shared/lib/isomorphic/path';
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/**
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* MultiFileWriter is a utility for writing multiple files in parallel that
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* guarantees that all files will be written after their containing directory
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* is created, and that the directory will only be created once.
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*/ export class MultiFileWriter {
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constructor(/**
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* The file system methods to use.
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*/ fs){
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this.fs = fs;
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this.tasks = [];
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}
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/**
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* Finds or creates a task for a directory.
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*
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* @param directory - The directory to find or create a task for.
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* @returns The task for the directory.
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*/ findOrCreateTask(directory) {
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// See if this directory already has a task to create it.
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for (const task of this.tasks){
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if (task[0] === directory) {
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return task;
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}
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}
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const promise = this.fs.mkdir(directory);
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// Attach a catch handler so that it doesn't throw an unhandled promise
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// rejection warning.
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promise.catch(()=>{});
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// Otherwise, create a new task for this directory.
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const task = [
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directory,
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promise,
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[]
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];
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this.tasks.push(task);
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return task;
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}
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/**
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* Appends a file to the writer to be written after its containing directory
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* is created. The file writer should be awaited after all the files have been
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* appended. Any async operation that occurs between appending and awaiting
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* may cause an unhandled promise rejection warning and potentially crash the
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* process.
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*
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* @param filePath - The path to the file to write.
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* @param data - The data to write to the file.
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*/ append(filePath, data) {
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// Find or create a task for the directory that contains the file.
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const task = this.findOrCreateTask(path.dirname(filePath));
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const promise = task[1].then(()=>this.fs.writeFile(filePath, data));
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// Attach a catch handler so that it doesn't throw an unhandled promise
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// rejection warning.
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promise.catch(()=>{});
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// Add the file write to the task AFTER the directory promise has resolved.
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task[2].push(promise);
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}
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/**
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* Returns a promise that resolves when all the files have been written.
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*/ wait() {
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return Promise.all(this.tasks.flatMap((task)=>task[2]));
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}
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}
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//# sourceMappingURL=multi-file-writer.js.map
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