Create a dedicated type for PushCondition::RoomMemberCount::is

ruma-common/Cargo.toml

@@ -11,6 +11,7 @@ repository = "https://github.com/ruma/ruma"
 edition = "2018"
 
 [dependencies]
+js_int = { version = "0.1.7", features = ["serde"] }
 matches = "0.1.8"
 ruma-serde = { version = "0.2.2", path = "../ruma-serde" }
 serde = { version = "1.0.113", features = ["derive"] }

ruma-common/src/push.rs

@@ -7,6 +7,9 @@ use std::fmt::{self, Formatter};
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use serde_json::value::RawValue as RawJsonValue;
 
+pub use room_member_count_is::{ComparisonOperator, RoomMemberCountIs};
+
+mod room_member_count_is;
 mod tweak_serde;
 
 /// A push ruleset scopes a set of rules according to some criteria.
@@ -229,11 +232,8 @@ pub enum PushCondition {
 
     /// This matches the current number of members in the room.
     RoomMemberCount {
-        /// A decimal integer optionally prefixed by one of `==`, `<`, `>`, `>=` or `<=`.
-        ///
-        /// A prefix of `<` matches rooms where the member count is strictly less than the given
-        /// number and so forth. If no prefix is present, this parameter defaults to `==`.
-        is: String,
+        /// The condition on the current number of members in the room.
+        is: RoomMemberCountIs,
     },
 
     /// This takes into account the current power levels in the room, ensuring the sender of the
@@ -249,10 +249,11 @@ pub enum PushCondition {
 
 #[cfg(test)]
 mod tests {
+    use js_int::uint;
     use matches::assert_matches;
     use serde_json::{from_value as from_json_value, json, to_value as to_json_value};
 
-    use super::{Action, PushCondition, Tweak};
+    use super::{Action, PushCondition, RoomMemberCountIs, Tweak};
 
     #[test]
     fn serialize_string_action() {
@@ -349,7 +350,10 @@ mod tests {
             "kind": "room_member_count"
         });
         assert_eq!(
-            to_json_value(&PushCondition::RoomMemberCount { is: "2".to_string() }).unwrap(),
+            to_json_value(&PushCondition::RoomMemberCount {
+                is: RoomMemberCountIs::from(uint!(2))
+            })
+            .unwrap(),
             json_data
         );
     }
@@ -398,7 +402,7 @@ mod tests {
         assert_matches!(
             from_json_value::<PushCondition>(json_data).unwrap(),
             PushCondition::RoomMemberCount { is }
-            if is == "2"
+            if is == RoomMemberCountIs::from(uint!(2))
         );
     }
 

ruma-common/src/push/room_member_count_is.rs

@@ -0,0 +1,209 @@
+use std::{
+    fmt::{self, Display, Formatter},
+    ops::{Bound, RangeBounds, RangeFrom, RangeTo, RangeToInclusive},
+    str::FromStr,
+};
+
+use js_int::UInt;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+/// One of `==`, `<`, `>`, `>=` or `<=`.
+///
+/// Used by `RoomMemberCountIs`. Defaults to `==`.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum ComparisonOperator {
+    /// Equals
+    Eq,
+    /// Less than
+    Lt,
+    /// Greater than
+    Gt,
+    /// Greater or equal
+    Ge,
+    /// Less or equal
+    Le,
+}
+
+impl Default for ComparisonOperator {
+    fn default() -> Self {
+        ComparisonOperator::Eq
+    }
+}
+
+/// A decimal integer optionally prefixed by one of `==`, `<`, `>`, `>=` or `<=`.
+///
+/// A prefix of `<` matches rooms where the member count is strictly less than the given
+/// number and so forth. If no prefix is present, this parameter defaults to `==`.
+///
+/// Can be constructed from a number or a range:
+/// ```
+/// use js_int::uint;
+/// use ruma_common::push::RoomMemberCountIs;
+///
+/// // equivalent to `is: "3"` or `is: "==3"`
+/// let exact = RoomMemberCountIs::from(uint!(3));
+///
+/// // equivalent to `is: ">=3"`
+/// let greater_or_equal = RoomMemberCountIs::from(uint!(3)..);
+///
+/// // equivalent to `is: "<3"`
+/// let less = RoomMemberCountIs::from(..uint!(3));
+///
+/// // equivalent to `is: "<=3"`
+/// let less_or_equal = RoomMemberCountIs::from(..=uint!(3));
+///
+/// // An exclusive range can be constructed with `RoomMemberCountIs::gt`:
+/// // (equivalent to `is: ">3"`)
+/// let greater = RoomMemberCountIs::gt(uint!(3));
+/// ```
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub struct RoomMemberCountIs {
+    /// One of `==`, `<`, `>`, `>=`, `<=`, or no prefix.
+    pub prefix: ComparisonOperator,
+    /// The number of people in the room.
+    pub count: UInt,
+}
+
+impl RoomMemberCountIs {
+    /// Creates an instance of `RoomMemberCount` equivalent to `<X`,
+    /// where X is the specified member count.
+    pub fn gt(count: UInt) -> Self {
+        RoomMemberCountIs { prefix: ComparisonOperator::Gt, count }
+    }
+}
+
+impl From<UInt> for RoomMemberCountIs {
+    fn from(x: UInt) -> Self {
+        RoomMemberCountIs { prefix: ComparisonOperator::Eq, count: x }
+    }
+}
+
+impl From<RangeFrom<UInt>> for RoomMemberCountIs {
+    fn from(x: RangeFrom<UInt>) -> Self {
+        RoomMemberCountIs { prefix: ComparisonOperator::Ge, count: x.start }
+    }
+}
+
+impl From<RangeTo<UInt>> for RoomMemberCountIs {
+    fn from(x: RangeTo<UInt>) -> Self {
+        RoomMemberCountIs { prefix: ComparisonOperator::Lt, count: x.end }
+    }
+}
+
+impl From<RangeToInclusive<UInt>> for RoomMemberCountIs {
+    fn from(x: RangeToInclusive<UInt>) -> Self {
+        RoomMemberCountIs { prefix: ComparisonOperator::Le, count: x.end }
+    }
+}
+
+impl Display for RoomMemberCountIs {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        use ComparisonOperator::*;
+
+        let prefix = match self.prefix {
+            Eq => "",
+            Lt => "<",
+            Gt => ">",
+            Ge => ">=",
+            Le => "<=",
+        };
+
+        write!(f, "{}{}", prefix, self.count)
+    }
+}
+
+impl Serialize for RoomMemberCountIs {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let s = self.to_string();
+        s.serialize(serializer)
+    }
+}
+
+impl FromStr for RoomMemberCountIs {
+    type Err = js_int::ParseIntError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        use ComparisonOperator::*;
+
+        let (prefix, count_str) = match s {
+            s if s.starts_with("<=") => (Le, &s[2..]),
+            s if s.starts_with('<') => (Lt, &s[1..]),
+            s if s.starts_with(">=") => (Ge, &s[2..]),
+            s if s.starts_with('>') => (Gt, &s[1..]),
+            s if s.starts_with("==") => (Eq, &s[2..]),
+            s => (Eq, s),
+        };
+
+        Ok(RoomMemberCountIs { prefix, count: UInt::from_str(count_str)? })
+    }
+}
+
+impl<'de> Deserialize<'de> for RoomMemberCountIs {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        FromStr::from_str(&s).map_err(serde::de::Error::custom)
+    }
+}
+
+impl RangeBounds<UInt> for RoomMemberCountIs {
+    fn start_bound(&self) -> Bound<&UInt> {
+        use ComparisonOperator::*;
+
+        match self.prefix {
+            Eq => Bound::Included(&self.count),
+            Lt | Le => Bound::Unbounded,
+            Gt => Bound::Excluded(&self.count),
+            Ge => Bound::Included(&self.count),
+        }
+    }
+
+    fn end_bound(&self) -> Bound<&UInt> {
+        use ComparisonOperator::*;
+
+        match self.prefix {
+            Eq => Bound::Included(&self.count),
+            Gt | Ge => Bound::Unbounded,
+            Lt => Bound::Excluded(&self.count),
+            Le => Bound::Included(&self.count),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::ops::RangeBounds;
+
+    use js_int::uint;
+
+    use super::RoomMemberCountIs;
+
+    #[test]
+    fn eq_range_contains_its_own_count() {
+        let count = 2u32.into();
+        let range = RoomMemberCountIs::from(count);
+
+        assert!(range.contains(&count));
+    }
+
+    #[test]
+    fn ge_range_contains_large_number() {
+        let range = RoomMemberCountIs::from(uint!(2)..);
+        let large_number = 9001u32.into();
+
+        assert!(range.contains(&large_number));
+    }
+
+    #[test]
+    fn gt_range_does_not_contain_initial_point() {
+        let range = RoomMemberCountIs::gt(uint!(2));
+        let initial_point = uint!(2);
+
+        assert!(!range.contains(&initial_point));
+    }
+}