diff --git a/src/cget/Cache.ts b/src/cget/Cache.ts
index d437c7f..85e9f5f 100644
--- a/src/cget/Cache.ts
+++ b/src/cget/Cache.ts
@@ -103,7 +103,7 @@ export class Cache {
 
 	createCachePath(urlRemote: string) {
 		return(this.getCachePath(urlRemote).then((cachePath: string) => {
-			return(mkdirp(path.dirname(cachePath)).then(() => cachePath));
+			return(mkdirp(path.dirname(cachePath), this.indexName).then(() => cachePath));
 		}));
 	}
 
diff --git a/src/cget/Task.ts b/src/cget/Task.ts
index d143e7a..be2a9ca 100644
--- a/src/cget/Task.ts
+++ b/src/cget/Task.ts
@@ -3,16 +3,22 @@
 
 import * as Promise from 'bluebird';
 
+/** Task wraps a promise, delaying it until some resource gets less busy. */
+
 export class Task<ResultType> {
 	constructor(func?: () => Promise<ResultType>) {
 		this.func = func;
 	}
 
+	/** Start the task immediately and call onFinish callback when done. */
+
 	start(onFinish: (err?: NodeJS.ErrnoException) => void) {
 		// These fix atom-typescript syntax highlight: ))
 		return(this.func().finally(onFinish));
 	}
 
+	/** Wrap task result in a new promise so it can be resolved later. */
+
 	delay() {
 		return(new Promise((resolve: (result: ResultType) => void, reject: (err: any) => void) => {
 			this.resolve = resolve;
@@ -20,6 +26,8 @@ export class Task<ResultType> {
 		}));
 	}
 
+	/** Resolve the result of a delayed task and call onFinish when done. */
+
 	resume(onFinish: (err?: NodeJS.ErrnoException) => void) {
 		// These fix atom-typescript syntax highlight: ))
 		return(this.start(onFinish).then(this.resolve).catch(this.reject));
diff --git a/src/cget/TaskQueue.ts b/src/cget/TaskQueue.ts
index 66365ab..88caa0b 100644
--- a/src/cget/TaskQueue.ts
+++ b/src/cget/TaskQueue.ts
@@ -4,6 +4,9 @@
 import {Task} from './Task'
 
 export class TaskQueue {
+	/** Add a new task to the queue.
+	  * It will start when the number of other concurrent tasks is low enough. */
+
 	add(task: Task<any>) {
 		if(this.busyCount < TaskQueue.concurrency) {
 			// Start the task immediately.
@@ -11,15 +14,17 @@ export class TaskQueue {
 			++this.busyCount;
 			return(task.start(() => this.next()));
 		} else {
-			// Schedule the task and return a promise that will behave exactly
-			// like what task.start() returns.
+			// Schedule the task and return a promise resolving
+			// to the result of task.start().
 
 			this.backlog.push(task);
 			return(task.delay());
 		}
 	}
 
-	next() {
+	/** Start the next task from the backlog. */
+
+	private next() {
 		var task = this.backlog.shift();
 
 		if(task) task.resume(() => this.next());
diff --git a/src/cget/util.ts b/src/cget/util.ts
index 7592828..970d1db 100644
--- a/src/cget/util.ts
+++ b/src/cget/util.ts
@@ -8,6 +8,8 @@ import * as url from 'url';
 import * as path from 'path';
 import * as Promise from 'bluebird';
 
+/** Asynchronous versions of fs methods, wrapped by Bluebird. */
+
 export var fsa = {
 	stat: Promise.promisify(fs.stat),
 	open: Promise.promisify(fs.open),
@@ -22,6 +24,8 @@ export var fsa = {
 var againSymbol = {};
 var again = () => againSymbol;
 
+/** Promise while loop. */
+
 export function repeat<T>(fn: (again: () => {}) => Promise<T>): Promise<T> {
 	return(Promise.try(() =>
 		fn(again)
@@ -30,6 +34,8 @@ export function repeat<T>(fn: (again: () => {}) => Promise<T>): Promise<T> {
 	));
 }
 
+/** Copy all members of src object to dst object. */
+
 export function extend(dst: {[key: string]: any}, src: {[key: string]: any}) {
 	for(var key of Object.keys(src)) {
 		dst[key] = src[key];
@@ -38,11 +44,17 @@ export function extend(dst: {[key: string]: any}, src: {[key: string]: any}) {
 	return(dst);
 }
 
+/** Make shallow clone of object. */
+
 export function clone(src: Object) {
 	return(extend({}, src));
 }
 
-export function mkdirp(pathName: string) {
+/** Create a new directory and its parent directories.
+  * If a path component to create conflicts with an existing file,
+  * rename to file to <component>/<indexName>. */
+
+export function mkdirp(pathName: string, indexName: string) {
 	var partList = path.resolve(pathName).split(path.sep);
 	var prefixList = partList.slice(0);
 	var pathPrefix: string;
@@ -59,14 +71,14 @@ export function mkdirp(pathName: string) {
 				// Trying to convert a file into a directory.
 				// Rename the file to indexName and move it into the new directory.
 
-				var tempPath = pathPrefix + '.' + this.makeTempSuffix(6);
+				var tempPath = pathPrefix + '.' + makeTempSuffix(6);
 
 				return(Promise.try(() =>
 					fsa.rename(pathPrefix, tempPath)
 				).then(() =>
 					fsa.mkdir(pathPrefix)
 				).then(() =>
-					fsa.rename(tempPath, path.join(pathPrefix, this.indexName))
+					fsa.rename(tempPath, path.join(pathPrefix, indexName))
 				));
 			} else if(!stats.isDirectory()) {
 				throw(new Error('Tried to create a directory inside something weird: ' + pathPrefix));
@@ -99,7 +111,7 @@ export function mkdirp(pathName: string) {
 	));
 }
 
-// Create a string of random letters and numbers.
+/** Create a string of random letters and numbers. */
 
 export function makeTempSuffix(length: number) {
 	return(