calendar: Support custom matcher (#873)

See #870

crates/story/src/date_picker_story.rs

@@ -1,4 +1,4 @@
-use chrono::{Days, Duration, Utc};
+use chrono::{Datelike, Days, Duration, Utc};
 use gpui::{
     px, App, AppContext, Context, Entity, Focusable, IntoElement, ParentElement as _, Render,
     Styled as _, Subscription, Window,
@@ -15,6 +15,7 @@ pub struct DatePickerStory {
     date_picker: Entity<DatePickerState>,
     date_picker_small: Entity<DatePickerState>,
     date_picker_large: Entity<DatePickerState>,
+    data_picker_custom: Entity<DatePickerState>,
     date_picker_value: Option<String>,
     date_range_picker: Entity<DatePickerState>,
     default_range_mode_picker: Entity<DatePickerState>,
@@ -73,6 +74,16 @@ impl DatePickerStory {
             picker.set_date(now, window, cx);
             picker
         });
+        let data_picker_custom = cx.new(|cx| {
+            let mut picker = DatePickerState::new(window, cx);
+            picker.set_disabled(
+                calendar::Matcher::custom(|date| date.day0() < 5),
+                window,
+                cx,
+            );
+            picker.set_date(now, window, cx);
+            picker
+        });
         let date_range_picker = cx.new(|cx| {
             let mut picker = DatePickerState::new(window, cx);
             picker.set_date(
@@ -107,6 +118,7 @@ impl DatePickerStory {
             date_picker,
             date_picker_large,
             date_picker_small,
+            data_picker_custom,
             date_range_picker,
             default_range_mode_picker,
             date_picker_value: None,
@@ -183,6 +195,11 @@ impl Render for DatePickerStory {
                         .width(px(300.)),
                 ),
             )
+            .child(
+                section("Custom (First 5 days of each month disabled)")
+                    .max_w_md()
+                    .child(DatePicker::new(&self.data_picker_custom)),
+            )
             .child(
                 section("Date Range").max_w_md().child(
                     DatePicker::new(&self.date_range_picker)

crates/ui/src/time/calendar.rs

@@ -179,6 +179,13 @@ pub enum Matcher {
     /// })
     /// Will match the days that are between 2020-01-01 and 2020-01-03.
     Range(RangeMatcher),
+    /// Match dates using a custom function.
+    ///
+    /// let matcher = Matcher::Custom(Box::new(|date: &NaiveDate| {
+    ///     date.day0() < 5
+    /// }));
+    /// Will match first 5 days of each month
+    Custom(Box<dyn Fn(&NaiveDate) -> bool + Send + Sync>),
 }
 
 impl From<Vec<u32>> for Matcher {
@@ -187,6 +194,15 @@ impl From<Vec<u32>> for Matcher {
     }
 }
 
+impl<F> From<F> for Matcher
+where
+    F: Fn(&NaiveDate) -> bool + Send + Sync +'static,
+{
+    fn from(f: F) -> Self {
+        Matcher::Custom(Box::new(f))
+    }
+}
+
 impl Matcher {
     pub fn interval(before: Option<NaiveDate>, after: Option<NaiveDate>) -> Self {
         Matcher::Interval(IntervalMatcher { before, after })
@@ -209,6 +225,7 @@ impl Matcher {
                 let to_check = range.to.map_or(false, |to| date > &to);
                 !from_check && !to_check
             }
+            Matcher::Custom(f) => f(date),
         }
     }
 
@@ -219,6 +236,13 @@ impl Matcher {
             _ => false,
         }
     }
+
+    pub fn custom<F>(f: F) -> Self
+    where
+        F: Fn(&NaiveDate) -> bool + Send + Sync + 'static,
+    {
+        Matcher::Custom(Box::new(f))
+    }
 }
 
 /// Use to store the state of the calendar.