Add trailing_input modifier to end

Author: jhpratt

time-macros/src/format_description/format_item.rs

@@ -207,7 +207,9 @@ component_definition! {
         Day = "day" {
             padding = "padding": Option<Padding> => padding,
         },
-        End = "end" {},
+        End = "end" {
+            trailing_input = "trailing_input": Option<TrailingInput> => trailing_input,
+        },
         Hour = "hour" {
             padding = "padding": Option<Padding> => padding,
             base = "repr": Option<HourBase> => is_12_hour_clock,
@@ -382,6 +384,12 @@ modifier! {
         OneOrMore = b"1+",
     }
 
+    enum TrailingInput {
+        #[default]
+        Prohibit = b"prohibit",
+        Discard = b"discard",
+    }
+
     enum UnixTimestampPrecision {
         #[default]
         Second = b"second",

time-macros/src/format_description/public/modifier.rs

@@ -266,5 +266,14 @@ to_tokens! {
 }
 
 to_tokens! {
-    pub(crate) struct End {}
+    pub(crate) enum TrailingInput {
+        Prohibit,
+        Discard,
+    }
+}
+
+to_tokens! {
+    pub(crate) struct End {
+        pub(crate) trailing_input: TrailingInput = TrailingInput::Prohibit,
+    }
 }

time/src/format_description/modifier.rs

@@ -293,12 +293,22 @@ pub struct UnixTimestamp {
     pub sign_is_mandatory: bool,
 }
 
+/// Whether trailing input after the declared end is permitted.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum TrailingInput {
+    /// Trailing input is not permitted and will cause an error.
+    Prohibit,
+    /// Trailing input is permitted but discarded.
+    Discard,
+}
+
 /// The end of input.
-///
-/// There is currently not customization for this modifier.
 #[non_exhaustive]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct End;
+pub struct End {
+    /// How to handle any input after this component.
+    pub trailing_input: TrailingInput,
+}
 
 /// Generate the provided code if and only if `pub` is present.
 macro_rules! if_pub {
@@ -432,6 +442,10 @@ impl_const_default! {
         precision: UnixTimestampPrecision::Second,
         sign_is_mandatory: false,
     };
-    /// Creates a modifier used to represent the end of input.
-    @pub End => End;
+    /// Indicate that any trailing characters after the end of input are prohibited and will cause
+    /// an error when used with `parse`.
+    TrailingInput => Self::Prohibit;
+    /// Creates a modifier used to represent the end of input, not allowing any trailing input (i.e.
+    /// the input must be fully consumed).
+    @pub End => Self { trailing_input: TrailingInput::Prohibit };
 }

time/src/format_description/parse/format_item.rs

@@ -285,7 +285,9 @@ component_definition! {
         Day = "day" {
             padding = "padding": Option<Padding> => padding,
         },
-        End = "end" {},
+        End = "end" {
+            trailing_input = "trailing_input": Option<TrailingInput> => trailing_input,
+        },
         Hour = "hour" {
             padding = "padding": Option<Padding> => padding,
             base = "repr": Option<HourBase> => is_12_hour_clock,
@@ -487,6 +489,12 @@ modifier! {
         OneOrMore = b"1+",
     }
 
+    enum TrailingInput {
+        #[default]
+        Prohibit = b"prohibit",
+        Discard = b"discard",
+    }
+
     enum UnixTimestampPrecision {
         #[default]
         Second = b"second",

time/src/formatting/mod.rs

@@ -297,7 +297,7 @@ where
                 ))
             }
         },
-        End(modifier::End {}) => 0,
+        End(modifier::End { trailing_input: _ }) => 0,
 
         // This is functionally the same as a wildcard arm, but it will cause an error if a new
         // component is added. This is to avoid a bug where a new component, the code compiles, and

time/src/parsing/component.rs

@@ -471,14 +471,15 @@ pub(crate) fn parse_unix_timestamp(
     }
 }
 
-/// Parse the `end` component, which represents the end of input. If any input is remaining, `None`
-/// is returned.
+/// Parse the `end` component, which represents the end of input. If any input is remaining _and_
+/// trailing input is prohibited, `None` is returned. If trailing input is permitted, it is
+/// discarded.
 #[inline]
-pub(crate) const fn parse_end(input: &[u8], end: modifier::End) -> Option<ParsedItem<'_, ()>> {
-    let modifier::End {} = end;
+pub(crate) fn parse_end(input: &[u8], end: modifier::End) -> Option<ParsedItem<'_, ()>> {
+    let modifier::End { trailing_input } = end;
 
-    if input.is_empty() {
-        Some(ParsedItem(input, ()))
+    if trailing_input == modifier::TrailingInput::Discard || input.is_empty() {
+        Some(ParsedItem(b"", ()))
     } else {
         None
     }

time/tests/integration/macros.rs

@@ -347,7 +347,25 @@ fn format_description_coverage() {
     assert_eq!(
         format_description!("[end]"),
         &[BorrowedFormatItem::Component(Component::End(modifier!(
-            End
+            End {
+                trailing_input: TrailingInput::Prohibit,
+            }
+        )))]
+    );
+    assert_eq!(
+        format_description!("[end trailing_input:prohibit]"),
+        &[BorrowedFormatItem::Component(Component::End(modifier!(
+            End {
+                trailing_input: TrailingInput::Prohibit,
+            }
+        )))]
+    );
+    assert_eq!(
+        format_description!("[end trailing_input:discard]"),
+        &[BorrowedFormatItem::Component(Component::End(modifier!(
+            End {
+                trailing_input: TrailingInput::Discard,
+            }
         )))]
     );
 }

time/tests/integration/parse_format_description.rs

@@ -126,6 +126,11 @@ fn modifiers(
         (UnixTimestampPrecision::Nanosecond, "precision:nanosecond"),
     )]
     unix_timestamp_precision: _,
+    #[values(
+        (TrailingInput::Prohibit, "trailing_input:prohibit"),
+        (TrailingInput::Discard, "trailing_input:discard"),
+    )]
+    trailing_input: _,
 ) {}
 
 #[rstest]
@@ -242,6 +247,16 @@ fn day_component(padding: M<Padding>) {
     );
 }
 
+#[apply(modifiers)]
+fn end_component(trailing_input: M<TrailingInput>) {
+    assert_eq!(
+        parse_with_modifiers!("end", trailing_input),
+        Ok(vec![BorrowedFormatItem::Component(Component::End(
+            modifier_m!(End { trailing_input })
+        ))])
+    );
+}
+
 #[apply(modifiers)]
 fn minute_component(padding: M<Padding>) {
     assert_eq!(

time/tests/integration/parsing.rs

@@ -1941,6 +1941,13 @@ fn end() -> time::Result<()> {
         Time::parse("00:00", &fd::parse("[hour]:[minute][end]")?),
         Ok(time!(0:00))
     );
+    assert_eq!(
+        Time::parse(
+            "00:00abcdef",
+            &fd::parse("[hour]:[minute][end trailing_input:discard]")?
+        ),
+        Ok(time!(0:00))
+    );
     assert_eq!(
         Time::parse(
             "00:00:00",
@@ -1957,6 +1964,15 @@ fn end() -> time::Result<()> {
             error::ParseFromDescription::UnexpectedTrailingCharacters { .. }
         ))
     ));
+    assert!(matches!(
+        Time::parse(
+            "00:00:00",
+            &fd::parse_owned::<2>("[hour]:[minute][end trailing_input:discard]:[second]")?
+        ),
+        Err(error::Parse::ParseFromDescription(
+            error::ParseFromDescription::InvalidLiteral { .. }
+        ))
+    ));
 
     Ok(())
 }