feat(custom): ability to embed scripts in labels for dynamic content

Fully resolves #34.

docs/modules/Custom.md

@@ -1,5 +1,5 @@
 Allows you to compose custom modules consisting of multiple widgets, including popups. 
-Buttons can interact with the bar or execute commands on click.
+Labels can display dynamic content from scripts, and buttons can interact with the bar or execute commands on click.
 
 ![Custom module with a button on the bar, and the popup open. The popup contains a header, shutdown button and restart button.](https://user-images.githubusercontent.com/5057870/196058785-042ef171-7e77-4d5c-921a-eca03c6424bd.png)
 
@@ -24,10 +24,23 @@ It is well worth looking at the examples.
 | `name`        | `string`                     | `null`       | Widget name.                                                              |
 | `class`       | `string`                     | `null`       | Widget class name.                                                        |
 | `label`       | `string`                     | `null`       | [`label` and `button`] Widget text label. Pango markup supported.         |
-| `exec`        | `string`                     | `null`       | [`button`] Command to execute. More on this [below](#commands).           |
+| `on_click`    | `string`                     | `null`       | [`button`] Command to execute. More on this [below](#commands).           |
 | `orientation` | `horizontal` or `vertical`   | `horizontal` | [`box`] Whether child widgets should be horizontally or vertically added. |
 | `widgets`     | `Widget[]`                   | `[]`         | [`box`] List of widgets to add to this box.                               |
 
+### Labels
+
+Labels can interpolate text from scripts to dynamically show content. 
+This can be done by including scripts in `{{double braces}}` using the shorthand script syntax.
+
+For example, the following label would output your system uptime, updated every 30 seconds.
+
+```
+Uptime: {{30000:uptime -p | cut -d ' ' -f2-}}
+```
+
+Both polling and watching mode are supported. For more information on script syntax, see [here](script).
+
 ### Commands
 
 Buttons can execute commands that interact with the bar, 
@@ -35,7 +48,7 @@ as well as any arbitrary shell command.
 
 To execute shell commands, prefix them with an `!`. 
 For example, if you want to run `~/.local/bin/my-script.sh` on click, 
-you'd set `exec` to `!~/.local/bin/my-script.sh`.
+you'd set `on_click` to `!~/.local/bin/my-script.sh`.
 
 The following bar commands are supported:
 
@@ -44,7 +57,7 @@ The following bar commands are supported:
 - `popup:close`
 
 XML is arguably better-suited and easier to read for this sort of markup, 
-but currently not supported.
+but currently is not supported.
 Nonetheless, it may be worth comparing the examples to the below equivalent
 to help get your head around what's going on:
 
@@ -53,15 +66,16 @@ to help get your head around what's going on:
 <?xml version="1.0" encoding="utf-8" ?>
 <custom class="power-menu">
     <bar>
-        <button name="power-btn" label="" exec="popup:toggle"/>
+        <button name="power-btn" label="" on_click="popup:toggle"/>
     </bar>
     <popup>
         <box orientation="vertical">
             <label name="header" label="Power menu" />
             <box>
-                <button class="power-btn" label="" exec="!shutdown now" />
+                <button class="power-btn" label="" on_click="!shutdown now" />
-                <button class="power-btn" label="" exec="!reboot" />
+                <button class="power-btn" label="" on_click="!reboot" />
             </box>
+            <label name="uptime" label="Uptime: {{30000:uptime -p | cut -d ' ' -f2-}}" />
         </box>
     </popup>
 </custom>
@@ -74,10 +88,12 @@ to help get your head around what's going on:
 {
   "end": [
     {
-      "type": "custom",
+      "type": "clock"
+    },
+    {
       "bar": [
         {
-          "exec": "popup:toggle",
+          "on_click": "popup:toggle",
           "label": "",
           "name": "power-btn",
           "type": "button"
@@ -99,21 +115,27 @@ to help get your head around what's going on:
               "widgets": [
                 {
                   "class": "power-btn",
-                  "exec": "!shutdown now",
+                  "on_click": "!shutdown now",
                   "label": "<span font-size='40pt'></span>",
                   "type": "button"
                 },
                 {
                   "class": "power-btn",
-                  "exec": "!reboot",
+                  "on_click": "!reboot",
                   "label": "<span font-size='40pt'></span>",
                   "type": "button"
                 }
               ]
+            },
+            {
+              "label": "Uptime: {{30000:uptime -p | cut -d ' ' -f2-}}",
+              "name": "uptime",
+              "type": "label"
             }
           ]
         }
-      ]
+      ],
+      "type": "custom"
     }
   ]
 }
@@ -125,12 +147,15 @@ to help get your head around what's going on:
 <summary>TOML</summary>
 
 ```toml
+[[end]]
+type = 'clock'
+
 [[end]]
 class = 'power-menu'
 type = 'custom'
 
 [[end.bar]]
-exec = 'popup:toggle'
+on_click = 'popup:toggle'
 label = ''
 name = 'power-btn'
 type = 'button'
@@ -149,15 +174,20 @@ type = 'box'
 
 [[end.popup.widgets.widgets]]
 class = 'power-btn'
-exec = '!shutdown now'
+on_click = '!shutdown now'
 label = '''<span font-size='40pt'></span>'''
 type = 'button'
 
 [[end.popup.widgets.widgets]]
 class = 'power-btn'
-exec = '!reboot'
+on_click = '!reboot'
 label = '''<span font-size='40pt'></span>'''
 type = 'button'
+
+[[end.popup.widgets]]
+label = '''Uptime: {{30000:uptime -p | cut -d ' ' -f2-}}'''
+name = 'uptime'
+type = 'label'
 ```
 
 </details>
@@ -167,9 +197,9 @@ type = 'button'
 
 ```yaml
 end:
-- type: custom
+- type: clock
-  bar:
+- bar:
-  - exec: popup:toggle
+  - on_click: popup:toggle
     label: 
     name: power-btn
     type: button
@@ -184,13 +214,17 @@ end:
     - type: box
       widgets:
       - class: power-btn
-        exec: '!shutdown now'
+        on_click: '!shutdown now'
         label: <span font-size='40pt'></span>
         type: button
       - class: power-btn
-        exec: '!reboot'
+        on_click: '!reboot'
         label: <span font-size='40pt'></span>
         type: button
+    - label: 'Uptime: {{30000:uptime -p | cut -d '' '' -f2-}}'
+      name: uptime
+      type: label
+  type: custom
 ```
 
 </details>
@@ -204,7 +238,7 @@ let {
         type = "custom"
         class = "power-menu"
 
-        bar = [ { type = "button" name="power-btn" label = "" exec = "popup:toggle" } ]
+        bar = [ { type = "button" name="power-btn" label = "" on_click = "popup:toggle" } ]
 
         popup = [ {
             type = "box"
@@ -214,10 +248,11 @@ let {
                 {
                     type = "box"
                     widgets = [
-                        { type = "button" class="power-btn" label = "<span font-size='40pt'></span>" exec = "!shutdown now" }
+                        { type = "button" class="power-btn" label = "<span font-size='40pt'></span>" on_click = "!shutdown now" }
-                        { type = "button" class="power-btn" label = "<span font-size='40pt'></span>" exec = "!reboot" }
+                        { type = "button" class="power-btn" label = "<span font-size='40pt'></span>" on_click = "!reboot" }
                     ]
                 }
+                { type = "label" name = "uptime" label = "Uptime: {{30000:uptime -p | cut -d ' ' -f2-}}" }
             ]
         } ]
     }

src/config.rs

@@ -27,7 +27,7 @@ pub struct CommonConfig {
 }
 
 #[derive(Debug, Deserialize, Clone)]
-#[serde(tag = "type", rename_all = "kebab-case")]
+#[serde(tag = "type", rename_all = "snake_case")]
 pub enum ModuleConfig {
     Clock(ClockModule),
     Mpd(MpdModule),
@@ -48,7 +48,7 @@ pub enum MonitorConfig {
 }
 
 #[derive(Debug, Deserialize, Copy, Clone, PartialEq, Eq)]
-#[serde(rename_all = "kebab-case")]
+#[serde(rename_all = "snake_case")]
 pub enum BarPosition {
     Top,
     Bottom,

src/main.rs

@@ -8,6 +8,7 @@ mod modules;
 mod popup;
 mod script;
 mod style;
+mod widgets;
 
 use crate::bar::create_bar;
 use crate::config::{Config, MonitorConfig};

src/modules/custom.rs

@@ -4,6 +4,7 @@ use crate::config::CommonConfig;
 use color_eyre::{Report, Result};
 use crate::script::Script;
 use gtk::prelude::*;
+use crate::widgets::DynamicLabel;
 use gtk::{Button, Label, Orientation};
 use serde::Deserialize;
 use tokio::spawn;
@@ -48,7 +49,7 @@ pub struct Widget {
 
 /// Supported GTK widget types
 #[derive(Debug, Deserialize, Clone)]
-#[serde(rename_all = "kebab-case")]
+#[serde(rename_all = "snake_case")]
 pub enum WidgetType {
     Box,
     Label,
@@ -60,7 +61,7 @@ impl Widget {
     fn add_to(self, parent: &gtk::Box, tx: Sender<ExecEvent>, bar_orientation: Orientation) {
         match self.widget_type {
             WidgetType::Box => parent.add(&self.into_box(&tx, bar_orientation)),
-            WidgetType::Label => parent.add(&self.into_label()),
+            WidgetType::Label => parent.add(&self.into_label().label),
             WidgetType::Button => parent.add(&self.into_button(tx, bar_orientation)),
         }
     }
@@ -94,7 +95,7 @@ impl Widget {
     }
 
     /// Creates a `gtk::Label` from this widget
-    fn into_label(self) -> Label {
+    fn into_label(self) -> DynamicLabel {
         let mut builder = Label::builder().use_markup(true);
 
         if let Some(name) = self.name {
@@ -103,15 +104,13 @@ impl Widget {
 
         let label = builder.build();
 
-        if let Some(text) = self.label {
-            label.set_markup(&text);
-        }
-
         if let Some(class) = self.class {
             label.style_context().add_class(&class);
         }
 
-        label
+        let text = self.label.map_or_else(String::new, |text| text);
+
+        DynamicLabel::new(label, &text)
     }
 
     /// Creates a `gtk::Button` from this widget

src/widgets/dynamic_label.rs

@@ -0,0 +1,125 @@
+use crate::script::{OutputStream, Script};
+use gtk::prelude::*;
+use indexmap::IndexMap;
+use std::sync::{Arc, Mutex};
+use tokio::spawn;
+
+#[derive(Debug)]
+enum DynamicLabelSegment {
+    Static(String),
+    Dynamic(Script),
+}
+
+pub struct DynamicLabel {
+    pub label: gtk::Label,
+}
+
+impl DynamicLabel {
+    pub fn new(label: gtk::Label, input: &str) -> Self {
+        let mut segments = vec![];
+
+        let mut chars = input.chars().collect::<Vec<_>>();
+        while !chars.is_empty() {
+            let char = &chars[..=1];
+
+            let (token, skip) = if let ['{', '{'] = char {
+                const SKIP_BRACKETS: usize = 4;
+
+                let str = chars
+                    .iter()
+                    .skip(2)
+                    .enumerate()
+                    .take_while(|(i, &c)| c != '}' && chars[i + 1] != '}')
+                    .map(|(_, c)| c)
+                    .collect::<String>();
+
+                let len = str.len();
+
+                (
+                    DynamicLabelSegment::Dynamic(Script::from(str.as_str())),
+                    len + SKIP_BRACKETS,
+                )
+            } else {
+                let str = chars
+                    .iter()
+                    .enumerate()
+                    .take_while(|(i, &c)| !(c == '{' && chars[i + 1] == '{'))
+                    .map(|(_, c)| c)
+                    .collect::<String>();
+
+                let len = str.len();
+
+                (DynamicLabelSegment::Static(str), len)
+            };
+
+            assert_ne!(skip, 0);
+
+            segments.push(token);
+            chars.drain(..skip);
+        }
+
+        let label_parts = Arc::new(Mutex::new(IndexMap::new()));
+        let (tx, rx) = glib::MainContext::channel(glib::PRIORITY_DEFAULT);
+
+        for (i, segment) in segments.into_iter().enumerate() {
+            match segment {
+                DynamicLabelSegment::Static(str) => {
+                    label_parts
+                        .lock()
+                        .expect("Failed to get lock on label parts")
+                        .insert(i, str);
+                }
+                DynamicLabelSegment::Dynamic(script) => {
+                    let tx = tx.clone();
+                    let label_parts = label_parts.clone();
+
+                    spawn(async move {
+                        script
+                            .run(|(out, _)| {
+                                if let OutputStream::Stdout(out) = out {
+                                    label_parts
+                                        .lock()
+                                        .expect("Failed to get lock on label parts")
+                                        .insert(i, out);
+                                    tx.send(()).expect("Failed to send update");
+                                }
+                            })
+                            .await;
+                    });
+                }
+            }
+        }
+
+        tx.send(()).expect("Failed to send update");
+
+        {
+            let label = label.clone();
+            rx.attach(None, move |_| {
+                let new_label = label_parts
+                    .lock()
+                    .expect("Failed to get lock on label parts")
+                    .iter()
+                    .map(|(_, part)| part.as_str())
+                    .collect::<String>();
+
+                label.set_label(new_label.as_str());
+
+                Continue(true)
+            });
+        }
+
+        Self { label }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test]
+    async fn test() {
+        gtk::init().unwrap();
+        let label = gtk::Label::new(None);
+        DynamicLabel::new(label, "Uptime: {{1000:uptime -p | cut -d ' ' -f2-}}");
+    }
+}

src/widgets/mod.rs

@@ -0,0 +1,3 @@
+mod dynamic_label;
+
+pub use dynamic_label::DynamicLabel;