upy-fs-hex: Add methods to get used and remaining FS space (#10)

Author: microbit-rosslowe

src/__tests__/micropython-fs-hex.spec.ts

@@ -95,6 +95,35 @@ describe('Test create method.', () => {
   });
 });
 
+describe('Test size operations.', () => {
+  it('Creates new files.', () => {
+    const microbitFs = new MicropythonFsHex(uPyHexFile);
+
+    expect(microbitFs.getStorageUsed()).toEqual(0);
+    expect(microbitFs.getStorageRemaining()).toEqual(27648);
+
+    microbitFs.create('chunk1.py', 'first 128 byte chunk');
+
+    expect(microbitFs.getStorageUsed()).toEqual(128);
+    expect(microbitFs.getStorageRemaining()).toEqual(27648 - 128);
+
+    microbitFs.create('chunk2.py', 'second 128 byte chunk');
+
+    expect(microbitFs.getStorageUsed()).toEqual(256);
+    expect(microbitFs.getStorageRemaining()).toEqual(27648 - 256);
+
+    microbitFs.create('chunk3.py', new Uint8Array(26800).fill(0x60));
+
+    expect(microbitFs.getStorageUsed()).toEqual(27648 - 128);
+    expect(microbitFs.getStorageRemaining()).toEqual(128);
+
+    microbitFs.create('chunk4.py', 'fourth chunk');
+
+    expect(microbitFs.getStorageUsed()).toEqual(27648);
+    expect(microbitFs.getStorageRemaining()).toEqual(0);
+  });
+});
+
 describe('Test write method.', () => {
   it('Throw error with invalid file name.', () => {
     const micropythonFs = new MicropythonFsHex(uPyHexFile);
@@ -504,7 +533,7 @@ describe('Test MicroPython hex filesystem size.', () => {
   it('Get how much available fs space there is in a MicroPython hex file.', () => {
     const micropythonFs = new MicropythonFsHex(uPyHexFile);
 
-    const totalSize = micropythonFs.getFsSize();
+    const totalSize = micropythonFs.getStorageSize();
 
     // Calculated by hand from the uPyHexFile v1.0.1 release.
     expect(totalSize).toEqual(27 * 1024);

src/micropython-fs-hex.ts

@@ -169,6 +169,38 @@ export class MicropythonFsHex implements FsInterface {
     return files;
   }
 
+  /**
+   * Calculate the MicroPython filesystem total size.
+   *
+   * @returns Size of the filesystem in bytes.
+   */
+  getStorageSize(): number {
+    return getIntelHexFsSize(this._intelHex);
+  }
+
+  /**
+   * @returns The total number of bytes currently used by files in the file system.
+   */
+  getStorageUsed(): number {
+    let total: number = 0;
+    Object.values(this._files).forEach(
+      (value) => (total += this.size(value.filename))
+    );
+    return total;
+  }
+
+  /**
+   * @returns The remaining storage of the file system in bytes.
+   */
+  getStorageRemaining(): number {
+    let total: number = 0;
+    const capacity: number = this.getStorageSize();
+    Object.values(this._files).forEach(
+      (value) => (total += this.size(value.filename))
+    );
+    return capacity - total;
+  }
+
   /**
    * Read the files included in a MicroPython hex string and add them to this
    * instance.
@@ -228,13 +260,4 @@ export class MicropythonFsHex implements FsInterface {
     });
     return addIntelHexFiles(finalHex, files);
   }
-
-  /**
-   * Calculate the MicroPython filesystem total size.
-   *
-   * @returns Size of the filesystem in bytes.
-   */
-  getFsSize(): number {
-    return getIntelHexFsSize(this._intelHex);
-  }
 }