feat(links): add ControlFlow to result to indicate early exit

This allows `Links` to signal, they have received everything they needed and let the `Data` stop providing `Link`s
SebastianSpeitel · Jan 24, 2024 · a930e1b · a930e1b
1 parent 72fd7e8
commit a930e1b
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Showing 7 changed files with 55 additions and 37 deletions.
diff --git a/src/data/ext.rs b/src/data/ext.rs
@@ -2,7 +2,7 @@
 use std::borrow::Cow;
 
 use crate::data::{format, BoxedData, Data};
-use crate::links::{LinkError, Links};
+use crate::links::{LinkError, Links, Result};
 use crate::query::Query;
 
 pub trait DataExt: Data {
@@ -156,25 +156,27 @@ pub trait DataExt: Data {
     #[inline]
     #[cfg(feature = "std")]
     fn as_list(&self) -> Result<Vec<BoxedData>, LinkError> {
+        use crate::links::CONTINUE;
+
         #[derive(Default)]
         struct ListLinks(Vec<BoxedData>);
 
         impl Links for ListLinks {
             #[inline]
-            fn push(&mut self, target: BoxedData, key: Option<BoxedData>) -> Result<(), LinkError> {
+            fn push(&mut self, target: BoxedData, key: Option<BoxedData>) -> Result {
                 if key.is_none() {
                     self.0.push(target);
                 }
-                Ok(())
+                CONTINUE
             }
             #[inline]
-            fn push_unkeyed(&mut self, target: BoxedData) -> Result<(), LinkError> {
+            fn push_unkeyed(&mut self, target: BoxedData) -> Result {
                 self.0.push(target);
-                Ok(())
+                CONTINUE
             }
             #[inline]
-            fn push_keyed(&mut self, _target: BoxedData, _key: BoxedData) -> Result<(), LinkError> {
-                Ok(())
+            fn push_keyed(&mut self, _target: BoxedData, _key: BoxedData) -> Result {
+                CONTINUE
             }
         }
 

diff --git a/src/data/format.rs b/src/data/format.rs
@@ -5,7 +5,7 @@ use std::{
 };
 
 use crate::data::{BoxedData, Data};
-use crate::links::{LinkError, Links};
+use crate::links::{Links, Result, CONTINUE};
 use crate::value::ValueBuiler;
 
 #[derive(Default, Debug)]
@@ -282,7 +282,7 @@ mod recursive {
     }
 
     impl<F: DataFormatter> Links for RecursiveLinks<'_, '_, F> {
-        fn push(&mut self, target: BoxedData, key: Option<BoxedData>) -> Result<(), LinkError> {
+        fn push(&mut self, target: BoxedData, key: Option<BoxedData>) -> Result {
             let link = FormattableLink::<F, _, _> {
                 key,
                 target,
@@ -291,7 +291,7 @@ mod recursive {
             };
             self.fmt_set.entry(&link);
 
-            Ok(())
+            CONTINUE
         }
     }
 }

diff --git a/src/data/impls/json.rs b/src/data/impls/json.rs
@@ -43,7 +43,9 @@ impl Data for Val {
 impl Data for Map<String, Val> {
     #[inline]
     fn provide_links(&self, links: &mut dyn Links) -> Result<(), LinkError> {
-        links.extend(self.iter().map(|(k, v)| (k.to_owned(), v.to_owned())))
+        links
+            .extend(self.iter().map(|(k, v)| (k.to_owned(), v.to_owned())))
+            .map(|_| ())
     }
 }
 

diff --git a/src/data/impls/std.rs b/src/data/impls/std.rs
@@ -251,7 +251,9 @@ where
 {
     #[inline]
     fn provide_links(&self, links: &mut dyn Links) -> Result<(), LinkError> {
-        links.extend(self.iter().map(|(k, t)| (k.to_owned(), t.to_owned())))
+        links
+            .extend(self.iter().map(|(k, t)| (k.to_owned(), t.to_owned())))
+            .map(|_| ())
     }
 }
 
@@ -262,7 +264,9 @@ where
 {
     #[inline]
     fn provide_links(&self, links: &mut dyn Links) -> Result<(), LinkError> {
-        links.extend(self.iter().map(::std::borrow::ToOwned::to_owned))
+        links
+            .extend(self.iter().map(::std::borrow::ToOwned::to_owned))
+            .map(|_| ())
     }
 }
 

diff --git a/src/data/impls/toml.rs b/src/data/impls/toml.rs
@@ -30,6 +30,8 @@ impl Data for Val {
 impl Data for Table {
     #[inline]
     fn provide_links(&self, links: &mut dyn Links) -> Result<(), LinkError> {
-        links.extend(self.iter().map(|(k, v)| (k.to_owned(), v.to_owned())))
+        links
+            .extend(self.iter().map(|(k, v)| (k.to_owned(), v.to_owned())))
+            .map(|_| ())
     }
 }
diff --git a/src/links.rs b/src/links.rs
@@ -1,3 +1,5 @@
+use std::ops::ControlFlow;
+
 use crate::data::{BoxedData, Data};
 
 pub mod impls;
@@ -8,9 +10,13 @@ pub mod prelude {
     pub use super::Links;
     pub use super::LinksExt;
     pub use super::Result;
+    pub use super::BREAK;
+    pub use super::CONTINUE;
 }
 
-pub type Result<T = (), E = LinkError> = core::result::Result<T, E>;
+pub type Result<T = ControlFlow<()>, E = LinkError> = core::result::Result<T, E>;
+pub const CONTINUE: Result = Ok(ControlFlow::Continue(()));
+pub const BREAK: Result = Ok(ControlFlow::Break(()));
 
 #[derive(Debug, thiserror::Error)]
 pub enum LinkError {
@@ -60,9 +66,11 @@ pub trait LinksExt: Links {
     #[inline]
     fn extend(&mut self, links: impl IntoIterator<Item = impl Link>) -> Result {
         for link in links {
-            link.build_into(self)?;
+            if link.build_into(self)?.is_break() {
+                return BREAK;
+            }
         }
-        Ok(())
+        CONTINUE
     }
 }
 

diff --git a/src/links/impls.rs b/src/links/impls.rs
@@ -3,7 +3,7 @@ use std::{
     hash::BuildHasher,
 };
 
-use super::{Links, Result};
+use super::{Links, Result, BREAK, CONTINUE};
 use crate::data::{
     unique::{Fixed, MaybeUnique},
     BoxedData,
@@ -13,7 +13,7 @@ impl Links for Vec<(Option<BoxedData>, BoxedData)> {
     #[inline]
     fn push(&mut self, target: BoxedData, key: Option<BoxedData>) -> Result {
         self.push((key, target));
-        Ok(())
+        CONTINUE
     }
 }
 
@@ -23,73 +23,73 @@ impl Links for Vec<(BoxedData, BoxedData)> {
         if let Some(key) = key {
             self.push((key, target));
         }
-        Ok(())
+        CONTINUE
     }
 
     #[inline]
     fn push_unkeyed(&mut self, _target: BoxedData) -> Result {
-        Ok(())
+        CONTINUE
     }
 
     #[inline]
     fn push_keyed(&mut self, target: BoxedData, key: BoxedData) -> Result {
         self.push((key, target));
-        Ok(())
+        CONTINUE
     }
 }
 
 impl Links for Vec<BoxedData> {
     #[inline]
     fn push(&mut self, target: BoxedData, _key: Option<BoxedData>) -> Result {
         self.push(target);
-        Ok(())
+        CONTINUE
     }
 
     #[inline]
     fn push_unkeyed(&mut self, target: BoxedData) -> Result {
         self.push(target);
-        Ok(())
+        CONTINUE
     }
 
     #[inline]
     fn push_keyed(&mut self, target: BoxedData, _key: BoxedData) -> Result {
         self.push(target);
-        Ok(())
+        CONTINUE
     }
 }
 
 impl Links for Option<(BoxedData, BoxedData)> {
     #[inline]
     fn push(&mut self, target: BoxedData, key: Option<BoxedData>) -> Result {
         if self.is_some() {
-            return Ok(());
+            return BREAK;
         }
         if let Some(key) = key {
             self.replace((key, target));
         }
-        Ok(())
+        BREAK
     }
 }
 
 impl Links for Option<(Option<BoxedData>, BoxedData)> {
     #[inline]
     fn push(&mut self, target: BoxedData, key: Option<BoxedData>) -> Result {
         if self.is_some() {
-            return Ok(());
+            return BREAK;
         }
         self.replace((key, target));
-        Ok(())
+        BREAK
     }
 }
 
 impl Links for Option<BoxedData> {
     #[inline]
     fn push(&mut self, target: BoxedData, _key: Option<BoxedData>) -> Result {
         if self.is_some() {
-            return Ok(());
+            return BREAK;
         }
         self.replace(target);
-        Ok(())
+        BREAK
     }
 }
 
@@ -101,18 +101,18 @@ impl<S: BuildHasher> Links for HashMap<Fixed<BoxedData>, BoxedData, S> {
                 self.insert(key, target);
             }
         }
-        Ok(())
+        CONTINUE
     }
     #[inline]
     fn push_unkeyed(&mut self, _target: BoxedData) -> Result {
-        Ok(())
+        CONTINUE
     }
     #[inline]
     fn push_keyed(&mut self, target: BoxedData, key: BoxedData) -> Result {
         if let Ok(key) = key.try_into_unique() {
             self.insert(key, target);
         }
-        Ok(())
+        CONTINUE
     }
 }
 
@@ -122,20 +122,20 @@ impl<S: BuildHasher> Links for HashSet<Fixed<BoxedData>, S> {
         if let Ok(target) = target.try_into_unique() {
             self.insert(target);
         }
-        Ok(())
+        CONTINUE
     }
     #[inline]
     fn push_unkeyed(&mut self, target: BoxedData) -> Result {
         if let Ok(target) = target.try_into_unique() {
             self.insert(target);
         }
-        Ok(())
+        CONTINUE
     }
     #[inline]
     fn push_keyed(&mut self, target: BoxedData, _key: BoxedData) -> Result {
         if let Ok(target) = target.try_into_unique() {
             self.insert(target);
         }
-        Ok(())
+        CONTINUE
     }
 }