feat: implement dynamic enum dispatch targets (#6)

Signed-off-by: tison <[email protected]>

.github/workflows/ci.yml

@@ -62,6 +62,7 @@ jobs:
       - name: Run examples
         run: |
           cargo run --example simple_stdio
+          cargo run --example fn_layout_filter
           cargo run --features="no-color" --example no_color_stdio
           cargo run --features="json" --example json_stdio
           cargo run --features="json,file" --example rolling_file

Cargo.toml

@@ -47,6 +47,10 @@ time = { version = "0.3", features = [
   "parsing",
 ], optional = true }
 
+[[example]]
+name = "fn_layout_filter"
+path = "examples/fn_layout_filter.rs"
+
 [[example]]
 name = "simple_stdio"
 path = "examples/simple_stdio.rs"

README.md

@@ -1,4 +1,4 @@
-# LogForth Project
+# Logforth Project
 
 A versatile and extensible logging implementation.
 

examples/fn_layout_filter.rs

@@ -0,0 +1,48 @@
+// Copyright 2024 tison <[email protected]>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use log::LevelFilter;
+use logforth::BoxDynFilter;
+use logforth::BoxDynLayout;
+use logforth::DispatchAppend;
+use logforth::FilterResult;
+use logforth::Logger;
+use logforth::StdoutAppend;
+
+fn main() {
+    let layout = BoxDynLayout::new(|record: &log::Record| {
+        let message = format!("[box dyn] {}", record.args());
+        Ok(message.into_bytes())
+        // ...or
+        // anyhow::bail!("boom: {}", message)
+    });
+
+    let filter = BoxDynFilter::new(|metadata: &log::Metadata| {
+        if metadata.level() <= LevelFilter::Info {
+            FilterResult::Accept
+        } else {
+            FilterResult::Reject
+        }
+    });
+
+    let append = StdoutAppend::default().with_layout(layout);
+    let append = DispatchAppend::new(append).filter(filter);
+    Logger::new().add_append(append).apply().unwrap();
+
+    log::error!("Hello error!");
+    log::warn!("Hello warn!");
+    log::info!("Hello info!");
+    log::debug!("Hello debug!");
+    log::trace!("Hello trace!");
+}

src/append/boxdyn.rs

@@ -0,0 +1,55 @@
+// Copyright 2024 tison <[email protected]>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::fmt::Debug;
+
+use log::Metadata;
+use log::Record;
+
+use crate::Append;
+use crate::AppendImpl;
+
+pub struct BoxDynAppend(Box<dyn Append + Send + Sync>);
+
+impl BoxDynAppend {
+    pub fn new(append: impl Append + Send + Sync + 'static) -> Self {
+        Self(Box::new(append))
+    }
+}
+
+impl Debug for BoxDynAppend {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "BoxDynAppend {{ ... }}")
+    }
+}
+
+impl Append for BoxDynAppend {
+    fn enabled(&self, metadata: &Metadata) -> bool {
+        (*self.0).enabled(metadata)
+    }
+
+    fn try_append(&self, record: &Record) -> anyhow::Result<()> {
+        (*self.0).try_append(record)
+    }
+
+    fn flush(&self) {
+        (*self.0).flush()
+    }
+}
+
+impl From<BoxDynAppend> for AppendImpl {
+    fn from(append: BoxDynAppend) -> Self {
+        AppendImpl::BoxDyn(append)
+    }
+}

src/append/boxlog.rs

@@ -0,0 +1,57 @@
+// Copyright 2024 tison <[email protected]>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::fmt::Debug;
+
+use log::Log;
+use log::Metadata;
+use log::Record;
+
+use crate::Append;
+use crate::AppendImpl;
+
+pub struct BoxLogAppend(Box<dyn Log>);
+
+impl Debug for BoxLogAppend {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "BoxLogAppend {{ ... }}")
+    }
+}
+
+impl BoxLogAppend {
+    pub fn new(log: impl Log + 'static) -> Self {
+        Self(Box::new(log))
+    }
+}
+
+impl Append for BoxLogAppend {
+    fn enabled(&self, metadata: &Metadata) -> bool {
+        (*self.0).enabled(metadata)
+    }
+
+    fn try_append(&self, record: &Record) -> anyhow::Result<()> {
+        (*self.0).log(record);
+        Ok(())
+    }
+
+    fn flush(&self) {
+        (*self.0).flush()
+    }
+}
+
+impl From<BoxLogAppend> for AppendImpl {
+    fn from(append: BoxLogAppend) -> Self {
+        AppendImpl::BoxLog(append)
+    }
+}

src/append/mod.rs

@@ -12,13 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+pub use boxdyn::*;
+pub use boxlog::*;
 pub use dispatch::*;
 #[cfg(feature = "fastrace")]
 pub use fastrace::*;
 #[cfg(feature = "file")]
 pub use file::*;
 pub use stdio::*;
 
+mod boxdyn;
+mod boxlog;
 mod dispatch;
 #[cfg(feature = "fastrace")]
 mod fastrace;
@@ -41,6 +45,8 @@ pub trait Append {
 
 #[derive(Debug)]
 pub enum AppendImpl {
+    BoxDyn(BoxDynAppend),
+    BoxLog(BoxLogAppend),
     Dispatch(DispatchAppend),
     #[cfg(feature = "fastrace")]
     Fastrace(FastraceAppend),
@@ -53,6 +59,8 @@ pub enum AppendImpl {
 impl Append for AppendImpl {
     fn enabled(&self, metadata: &log::Metadata) -> bool {
         match self {
+            AppendImpl::BoxDyn(append) => append.enabled(metadata),
+            AppendImpl::BoxLog(append) => append.enabled(metadata),
             AppendImpl::Dispatch(append) => append.enabled(metadata),
             #[cfg(feature = "fastrace")]
             AppendImpl::Fastrace(append) => append.enabled(metadata),
@@ -65,6 +73,8 @@ impl Append for AppendImpl {
 
     fn try_append(&self, record: &log::Record) -> anyhow::Result<()> {
         match self {
+            AppendImpl::BoxDyn(append) => append.try_append(record),
+            AppendImpl::BoxLog(append) => append.try_append(record),
             AppendImpl::Dispatch(append) => append.try_append(record),
             #[cfg(feature = "fastrace")]
             AppendImpl::Fastrace(append) => append.try_append(record),
@@ -77,6 +87,8 @@ impl Append for AppendImpl {
 
     fn flush(&self) {
         match self {
+            AppendImpl::BoxDyn(append) => append.flush(),
+            AppendImpl::BoxLog(append) => append.flush(),
             AppendImpl::Dispatch(append) => append.flush(),
             #[cfg(feature = "fastrace")]
             AppendImpl::Fastrace(append) => append.flush(),

src/filter/boxdyn.rs

@@ -0,0 +1,58 @@
+// Copyright 2024 tison <[email protected]>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::fmt::Debug;
+
+use log::Metadata;
+use log::Record;
+
+use crate::Filter;
+use crate::FilterImpl;
+use crate::FilterResult;
+
+pub struct BoxDynFilter(Box<dyn Filter + Send + Sync>);
+
+impl Debug for BoxDynFilter {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "BoxDynFilter {{ ... }}")
+    }
+}
+
+impl BoxDynFilter {
+    pub fn new(filter: impl Filter + Send + Sync + 'static) -> Self {
+        Self(Box::new(filter))
+    }
+}
+
+impl Filter for BoxDynFilter {
+    fn filter(&self, record: &Record) -> FilterResult {
+        (*self.0).filter(record)
+    }
+
+    fn filter_metadata(&self, metadata: &Metadata) -> FilterResult {
+        (*self.0).filter_metadata(metadata)
+    }
+}
+
+impl From<BoxDynFilter> for FilterImpl {
+    fn from(filter: BoxDynFilter) -> Self {
+        FilterImpl::BoxDyn(filter)
+    }
+}
+
+impl<T: Fn(&Metadata) -> FilterResult> Filter for T {
+    fn filter_metadata(&self, metadata: &Metadata) -> FilterResult {
+        self(metadata)
+    }
+}

src/filter/mod.rs

@@ -12,10 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use log::Metadata;
-use log::Record;
+pub use boxdyn::BoxDynFilter;
 pub use log_level::LogLevelFilter;
 
+mod boxdyn;
 mod log_level;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -29,27 +29,30 @@ pub enum FilterResult {
 }
 
 pub trait Filter {
-    fn filter(&self, _record: &Record) -> FilterResult {
+    fn filter(&self, _record: &log::Record) -> FilterResult {
         FilterResult::Neutral
     }
 
-    fn filter_metadata(&self, metadata: &Metadata) -> FilterResult;
+    fn filter_metadata(&self, metadata: &log::Metadata) -> FilterResult;
 }
 
 #[derive(Debug)]
 pub enum FilterImpl {
+    BoxDyn(BoxDynFilter),
     LogLevel(LogLevelFilter),
 }
 
 impl Filter for FilterImpl {
-    fn filter(&self, record: &Record) -> FilterResult {
+    fn filter(&self, record: &log::Record) -> FilterResult {
         match self {
+            FilterImpl::BoxDyn(filter) => filter.filter(record),
             FilterImpl::LogLevel(filter) => filter.filter(record),
         }
     }
 
-    fn filter_metadata(&self, metadata: &Metadata) -> FilterResult {
+    fn filter_metadata(&self, metadata: &log::Metadata) -> FilterResult {
         match self {
+            FilterImpl::BoxDyn(filter) => filter.filter_metadata(metadata),
             FilterImpl::LogLevel(filter) => filter.filter_metadata(metadata),
         }
     }