Added DataDevice reference (#212)

Author: AtibQur

sites/cheerpx/src/content/docs/11-guides/File-System-support.md

@@ -161,11 +161,11 @@ For more details on reading files using [`IDBDevice`](/docs/reference/CheerpX.ID
 
 ## DataDevice
 
-`DataDevice` is an in-memory filesystem useful for temporary data storage or passing data from JavaScript to the CheerpX environment.
+[`DataDevice`](/docs/reference/CheerpX.DataDevice) is an in-memory filesystem useful for temporary data storage or passing data from JavaScript to the CheerpX environment.
 
 ### Usage
 
-Create a DataDevice using the `CheerpX.DataDevice.create()` method:
+[`Create`](/docs/reference/CheerpX.DataDevice/create) a [`DataDevice`](/docs/reference/CheerpX.DataDevice) using the `CheerpX.DataDevice.create()` method:
 
 ```javascript
 const dataDevice = await CheerpX.DataDevice.create();
@@ -177,41 +177,12 @@ const cx = await CheerpX.Linux.create({
 
 ### Adding files
 
-You can add files to a DataDevice from JavaScript using the `writeFile` method:
+You can add files to a [`DataDevice`](/docs/reference/CheerpX.DataDevice) from JavaScript using the [`writeFile`](/docs/reference/CheerpX.DataDevice/writeFIle) method:
 
 ```javascript
 await dataDevice.writeFile("/filename", "File content here");
 ```
 
-### `dataDevice.writeFile`
-
-`CheerpX.DataDevice` provides a method to write data to new files within the mounted device. This utility is limited to creating files at the root level of the device.
-
-```js
-await dataDevice.writeFile(filename: string, contents: string | Uint8Array): Promise<void>
-```
-
-**Parameters**:
-
-- **filename**: A string representing the path to the file within the device, starting with a `/` (e.g., "/filename"). Do not include the mount point.
-- **contents**: The data to write to the file. Can be either a string or a Uint8Array.
-
-**Returns**:
-
-The method returns a Promise that resolves when the file has been created and written to. It doesn't return any value.
-
-Example:
-
-```js
-const dataDevice = await CheerpX.DataDevice.create();
-await dataDevice.writeFile("/filename", "contents");
-```
-
-> [!note] Note
->
-> - This is the only way to create files in this device.
-> - Modifying existing files or creating files in subdirectories is not possible.
-
 ## Block devices with ext2
 
 CheerpX supports ext2 filesystems, which can be configured as an overlay device. This allows for a flexible setup that can combine different storage types.

sites/cheerpx/src/content/docs/11-guides/input-output.md

@@ -88,9 +88,7 @@ console.log(await outputBlob.text());
 
 ## Accessing JS Data in the Filesystem via DataDevice
 
-The `DataDevice` API exposes JavaScript data via the filesystem. This device provides read-only access to a `Uint8Array` and a JavaScript `String`. It is particularly useful for transferring data from JavaScript to programs running in CheerpX.
-
-For more information, see the [CheerpX DataDevice].
+The [`DataDevice`](/docs/reference/CheerpX.DataDevice) API exposes JavaScript data via the filesystem. This device provides read-only access to a `Uint8Array` and a JavaScript `String`. It is particularly useful for transferring data from JavaScript to programs running in CheerpX.
 
 [CheerpX documentations]: https://cheerpx.io/docs/overview
 [CheerpX DataDevice]: https://cheerpx.io/docs/guides/File-System-support#datadevice

sites/cheerpx/src/content/docs/12-reference/CheerpX.DataDevice/create.md

@@ -0,0 +1,57 @@
+---
+title: create
+description: Create a CheerpX DataDevice instance to store temporary data in memory.
+---
+
+```ts
+namespace CheerpX {
+	class DataDevice {
+		static async create(): Promise<DataDevice>;
+	}
+}
+```
+
+## Parameters
+
+- None
+
+## Returns
+
+`CheerpX.DataDevice.create` returns a [Promise] that resolves to a `DataDevice` instance. You can use this instance to create a temporary in-memory filesystem in your CheerpX environment.
+
+## Example
+
+Create a `DataDevice` instance for in-memory storage.
+
+```ts {7, 13}
+// Create a read-only block device for a disk image stored on the HTTP server
+const blockDevice = await CheerpX.HttpBytesDevice.create("/cheerpXImage.ext2");
+// Make the block device read-write using a persistent IndexedDB overlay
+const idbDevice = await CheerpX.IDBDevice.create("block_idbDevice");
+const overlayDevice = await CheerpX.OverlayDevice.create(
+	blockDevice,
+	idbDevice
+);
+// Add a device to expose JavaScript data in the VM
+const dataDevice = await CheerpX.DataDevice.create();
+// Initialize the CheerpX environment
+const mountPoints = [
+	// Use the disk image as the filesystem root
+	{ type: "ext2", path: "/", dev: overlayDevice },
+	// Add the DataDevice to a known location
+	{ type: "dir", path: "/data", dev: dataDevice },
+];
+const cx = await CheerpX.Linux.create({
+	mounts: mountPoints,
+});
+```
+
+In this example, the `DataDevice` is created using `CheerpX.DataDevice.create()` and mounted at `/data` in the Linux environment inside the CheerpX system.
+
+If you’d like to learn more about related topics, check out these guides:
+
+- [Files and filesystems](/docs/guides/File-System-support) – Managing files and storage in CheerpX.
+- [Custom disk images](/docs/guides/custom-images) – Creating and using custom disk images.
+- [Input and output](/docs/guides/input-output) – Handling data flow in your environment.
+
+[Promise]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

sites/cheerpx/src/content/docs/12-reference/CheerpX.DataDevice/writeFIle.md

@@ -0,0 +1,97 @@
+---
+title: writeFile
+description: Write data to a new file in the CheerpX DataDevice.
+---
+
+```ts
+namespace CheerpX {
+	class DataDevice {
+		async writeFile(
+			filename: string,
+			contents: string | Uint8Array
+		): Promise<void>;
+	}
+}
+```
+
+## Parameters
+
+- **filename (`string`)** - The path to the file within the device, starting with a `/` (e.g., `/filename`). The path should not include the mount point.
+- **contents (`string | Uint8Array`)** - The data to write to the file. Can be either a string or a `Uint8Array`.
+
+## Returns
+
+`CheerpX.DataDevice.writeFile` returns a [Promise] that resolves when the file has been created and written to, but it does not return any value.
+
+## Example
+
+Write a file to the `DataDevice`.
+
+```ts {29}
+// Create a read-only block device for a disk image stored on the HTTP server
+const blockDevice = await CheerpX.HttpBytesDevice.create("/cheerpXImage.ext2");
+// Make the block device read-write using a persistent IndexedDB overlay
+const idbDevice = await CheerpX.IDBDevice.create("block_cpp");
+const overlayDevice = await CheerpX.OverlayDevice.create(
+	blockDevice,
+	idbDevice
+);
+// Add a device to expose JavaScript data in the VM
+const dataDevice = await CheerpX.DataDevice.create();
+// Initialize the CheerpX environment
+const mountPoints = [
+	// Use the disk image as the filesystem root
+	{ type: "ext2", path: "/", dev: overlayDevice },
+	// Add the DataDevice to a known location
+	{ type: "dir", path: "/data", dev: dataDevice },
+	// Add the required Linux pseudo-filesystem
+	{ type: "devs", path: "/dev" },
+	{ type: "devpts", path: "/dev/pts" },
+	{ type: "proc", path: "/proc" },
+];
+const cx = await CheerpX.Linux.create({
+	mounts: mountPoints,
+});
+
+// Setup the text console
+cx.setConsole(document.getElementById("console"));
+
+async function compileAndRun(cx, dataDevice, srcCode, inputName, outputName) {
+	// Make the source code available as a file
+	await dataDevice.writeFile("/" + inputName, srcCode);
+	// Compile the source code by calling g++
+	await cx.run(
+		"/usr/bin/g++",
+		["-v", "/data/" + inputName, "-o", "/" + outputName],
+		{
+			env: ["PATH=/usr/bin"],
+		}
+	);
+	await cx.run("/" + outputName, []);
+}
+
+const srcCode = `
+#include <iostream>
+
+int main()
+{
+    std::cout << "Hello World" << std::endl;
+    return 0;
+}
+`;
+await compileAndRun(cx, dataDevice, srcCode, "hello.cpp", "hello");
+```
+
+In this example:
+
+The `writeFile` method is used to write source code (`srcCode`) into a file (`hello.cpp`) on the `DataDevice`.
+
+After that, the CheerpX environment runs a `g++` command to compile the source code, and then executes the compiled file to output **Hello World**.
+
+If you’d like to learn more about related topics, check out these guides:
+
+- [Files and filesystems](/docs/guides/File-System-support) – Managing files and storage in CheerpX.
+- [Custom disk images](/docs/guides/custom-images) – Creating and using custom disk images.
+- [Input and output](/docs/guides/input-output) – Handling data flow in your environment.
+
+[Promise]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

sites/cheerpx/src/content/docs/20-faq.md

@@ -22,7 +22,7 @@ Yes, `WebDevice` can handle third-party origins as paths, but it's important to
 
 ## Why can't I execute files directly from a `DataDevice`?
 
-`DataDevice` in CheerpX does not have full support for Linux mode bits, and in particular it lacks the _**executable**_ bit. This means you can read data from it, but you cannot execute files directly from it. To execute files that are in a `DataDevice`, you need to first copy the files to a filesystem with complete support for mode bits, such as [`IDBDevice`](/docs/reference/CheerpX.IDBDevice) (IndexedDB) or Ext2.
+[`DataDevice`](/docs/reference/CheerpX.DataDevice) in CheerpX does not have full support for Linux mode bits, and in particular it lacks the _**executable**_ bit. This means you can read data from it, but you cannot execute files directly from it. To execute files that are in a [`DataDevice`](/docs/reference/CheerpX.DataDevice), you need to first copy the files to a filesystem with complete support for mode bits, such as [`IDBDevice`](/docs/reference/CheerpX.IDBDevice) (IndexedDB) or Ext2.
 
 ## Why can't CheerpX do what v86 does in terms of disk access and networking?