Fix scanimage -A parsing with [advanced]

Issue #564

There are cases where `scanimage -A` outputs an additional square bracketed item on a parameter line such as:

```
    --contrast -127..127 [0] [advanced]
```

The old regex only assumed this happened once - which was good enough for 6 years or so. It seems that it can happen twice.

The regex has been updated to have a non-greedy match for the first one (`default`) and there is a subsequent optional non-capturing group for the second, which for want of a better name is referred here as `meta`.

It turns out that this pattern has been seen before with `[read-only]` but that was benign since it was treated as a default to ignore. For that reason, the `enabled` flag has to be altered too.

Associated unit test added.

packages/server/src/classes/feature.js

@@ -28,10 +28,6 @@ module.exports = class Feature {
     this.load();
   }
 
-  get enabled() {
-    return !['inactive', 'read-only'].includes(this.default);
-  }
-
   asRange() {
     this.default = round(Number(this.default));
     const range = /(.*?)(?:\s|$)/g.exec(this.parameters);
@@ -68,10 +64,12 @@ module.exports = class Feature {
   }
 
   load() {
-    const match = /^\s*([-]{1,2}[-a-zA-Z0-9]+) ?(.*) \[(.*)\]$/g.exec(this.text);
+    const match = /^\s*([-]{1,2}[-a-zA-Z0-9]+) ?(.*?) \[(.*?)\](?: \[(.*?)\])?$/g.exec(this.text);
     this.name = match[1];
     this.default = match[3];
     this.parameters = match[2];
+    this.meta = match[4];
+    this.enabled = this.default !== 'inactive' && this.meta !== 'read-only';
 
     this.parameters = this.parameters.replace(/^auto\|/, '');
     if (this.enabled) {

packages/server/test/device.test.js

@@ -258,4 +258,39 @@ describe('Device', () => {
     assert.strictEqual(device.features['-y'].default, 431.8);
   });
 
+  it('scanimage-a13.txt', () => {
+    const file = FileInfo.create('test/resource/scanimage-a13.txt');
+    const device = Device.from(file.toText());
+
+    assert.strictEqual(device.id, 'hpaio:/usb/PSC_1600_series?serial=MY4C3C30Z5L0');
+    assert.deepStrictEqual(device.features['--mode'].options, ['Lineart', 'Gray', 'Color']);
+    assert.strictEqual(device.features['--mode'].default, 'Color');
+    assert.deepStrictEqual(device.features['--resolution'].options, [75, 100, 150, 200, 300, 600, 1200]);
+    assert.strictEqual(device.features['--resolution'].default, 75);
+    assert.strictEqual(device.features['--contrast'].limits[0], -127);
+    assert.strictEqual(device.features['--contrast'].limits[1], 127);
+    assert.strictEqual(device.features['--contrast'].interval, 1);
+    assert.strictEqual(device.features['--contrast'].default, 0);
+    assert.strictEqual(device.features['--contrast'].meta, 'advanced');
+    assert.strictEqual(device.features['--brightness'].limits[0], -127);
+    assert.strictEqual(device.features['--brightness'].limits[1], 127);
+    assert.strictEqual(device.features['--brightness'].interval, 1);
+    assert.strictEqual(device.features['--brightness'].default, 0);
+    assert.strictEqual(device.features['--brightness'].meta, 'advanced');
+    assert.deepStrictEqual(device.features['--source'].options, ['Flatbed']);
+    assert.strictEqual(device.features['--source'].default, 'Flatbed');
+    assert.strictEqual(device.features['--source'].meta, 'advanced');
+    assert.strictEqual(device.features['-l'].limits[0], 0);
+    assert.strictEqual(device.features['-l'].limits[1], 215.9);
+    assert.strictEqual(device.features['-l'].default, 0);
+    assert.strictEqual(device.features['-t'].limits[0], 0);
+    assert.strictEqual(device.features['-t'].limits[1], 296.9);
+    assert.strictEqual(device.features['-t'].default, 0);
+    assert.strictEqual(device.features['-x'].limits[0], 0);
+    assert.strictEqual(device.features['-x'].limits[1], 215.9);
+    assert.strictEqual(device.features['-x'].default, 215.9);
+    assert.strictEqual(device.features['-y'].limits[0], 0);
+    assert.strictEqual(device.features['-y'].limits[1], 296.9);
+    assert.strictEqual(device.features['-y'].default, 296.9);
+  });
 });

packages/server/test/resource/scanimage-a13.txt

@@ -0,0 +1,36 @@
+
+All options specific to device `hpaio:/usb/PSC_1600_series?serial=MY4C3C30Z5L0':
+  Scan mode:
+    --mode Lineart|Gray|Color [Color]
+        Selects the scan mode (e.g., lineart, monochrome, or color).
+    --resolution 75|100|150|200|300|600|1200dpi [75]
+        Sets the resolution of the scanned image.
+  Advanced:
+    --contrast -127..127 [0] [advanced]
+        Controls the contrast of the acquired image.
+    --brightness -127..127 [0] [advanced]
+        Controls the brightness of the acquired image.
+    --compression None|JPEG [JPEG] [advanced]
+        Selects the scanner compression method for faster scans, possibly at
+        the expense of image quality.
+    --jpeg-quality 0..100 [10] [advanced]
+        Sets the scanner JPEG compression factor. Larger numbers mean better
+        compression, and smaller numbers mean better image quality.
+    --batch-scan[=(yes|no)] [no] [advanced]
+        Enables continuous scanning with automatic document feeder (ADF).
+    --source Flatbed [Flatbed] [advanced]
+        Selects the scan source (such as a document-feeder).
+    --duplex[=(yes|no)] [inactive]
+        Enables scanning on both sides of the page.
+  Geometry:
+    --length-measurement Unknown|Approximate|Padded [Padded] [advanced]
+        Selects how the scanned image length is measured and reported, which
+        is impossible to know in advance for scrollfed scans.
+    -l 0..215.9mm [0]
+        Top-left x position of scan area.
+    -t 0..296.926mm [0]
+        Top-left y position of scan area.
+    -x 0..215.9mm [215.9]
+        Width of scan-area.
+    -y 0..296.926mm [296.926]
+        Height of scan-area.