Add FilteredLog utility to combine a Filter with a Log.

Cargo.toml

@@ -1,67 +1,6 @@
-[package]
-name = "env_logger"
-version = "0.10.1"
-description = """
-A logging implementation for `log` which is configured via an environment
-variable.
-"""
-repository = "https://github.com/rust-cli/env_logger"
-categories = ["development-tools::debugging"]
-keywords = ["logging", "log", "logger"]
-license = "MIT OR Apache-2.0"
-edition = "2021"
-rust-version = "1.60.0"  # MSRV
-include = [
-  "build.rs",
-  "src/**/*",
-  "Cargo.toml",
-  "Cargo.lock",
-  "LICENSE*",
-  "README.md",
-  "benches/**/*",
-  "examples/**/*",
-  "tests/**/*",
+[workspace]
+resolver = "2"
+members = [
+    "env_filter",
+    "env_logger",
 ]
-
-[package.metadata.docs.rs]
-all-features = true
-rustdoc-args = ["--cfg", "docsrs"]
-
-[package.metadata.release]
-pre-release-replacements = [
-  {file="CHANGELOG.md", search="Unreleased", replace="{{version}}", min=1},
-  {file="CHANGELOG.md", search="\\.\\.\\.HEAD", replace="...{{tag_name}}", exactly=1},
-  {file="CHANGELOG.md", search="ReleaseDate", replace="{{date}}", min=1},
-  {file="CHANGELOG.md", search="<!-- next-header -->", replace="<!-- next-header -->\n## [Unreleased] - ReleaseDate\n", exactly=1},
-  {file="CHANGELOG.md", search="<!-- next-url -->", replace="<!-- next-url -->\n[Unreleased]: https://github.com/rust-cli/env_logger/compare/{{tag_name}}...HEAD", exactly=1},
-]
-
-[features]
-default = ["auto-color", "humantime", "regex"]
-color = ["dep:termcolor"]
-auto-color = ["dep:is-terminal", "color"]
-humantime = ["dep:humantime"]
-regex = ["dep:regex"]
-
-[dependencies]
-log = { version = "0.4.8", features = ["std"] }
-regex = { version = "1.0.3", optional = true, default-features=false, features=["std", "perf"] }
-termcolor = { version = "1.1.1", optional = true }
-humantime = { version = "2.0.0", optional = true }
-is-terminal = { version = "0.4.0", optional = true }
-
-[[test]]
-name = "regexp_filter"
-harness = false
-
-[[test]]
-name = "log-in-log"
-harness = false
-
-[[test]]
-name = "log_tls_dtors"
-harness = false
-
-[[test]]
-name = "init-twice-retains-filter"
-harness = false

env_filter/Cargo.toml

@@ -0,0 +1,45 @@
+[package]
+name = "env_filter"
+version = "0.10.1"
+description = """
+A log filtering implementation for `log` which is configured via an environment
+variable.
+"""
+repository = "https://github.com/rust-cli/env_logger"
+categories = ["development-tools::debugging"]
+keywords = ["logging", "log", "logger"]
+license = "MIT OR Apache-2.0"
+edition = "2021"
+rust-version = "1.60.0"  # MSRV
+include = [
+  "build.rs",
+  "src/**/*",
+  "Cargo.toml",
+  "Cargo.lock",
+  "LICENSE*",
+  "README.md",
+  "benches/**/*",
+  "examples/**/*",
+  "tests/**/*",
+]
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[package.metadata.release]
+pre-release-replacements = [
+  {file="CHANGELOG.md", search="Unreleased", replace="{{version}}", min=1},
+  {file="CHANGELOG.md", search="\\.\\.\\.HEAD", replace="...{{tag_name}}", exactly=1},
+  {file="CHANGELOG.md", search="ReleaseDate", replace="{{date}}", min=1},
+  {file="CHANGELOG.md", search="<!-- next-header -->", replace="<!-- next-header -->\n## [Unreleased] - ReleaseDate\n", exactly=1},
+  {file="CHANGELOG.md", search="<!-- next-url -->", replace="<!-- next-url -->\n[Unreleased]: https://github.com/rust-cli/env_logger/compare/{{tag_name}}...HEAD", exactly=1},
+]
+
+[features]
+default = ["regex"]
+regex = ["dep:regex"]
+
+[dependencies]
+log = { version = "0.4.8", features = ["std"] }
+regex = { version = "1.0.3", optional = true, default-features=false, features=["std", "perf"] }

env_filter/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE

env_filter/LICENSE-MIT

@@ -0,0 +1 @@
+../LICENSE-MIT

env_filter/src/filtered_log.rs

@@ -0,0 +1,69 @@
+use super::Filter;
+use log::Log;
+
+/// Wrapper that combines a [`Filter`] with an existing [`log::Log`] implementation.
+///
+/// Records that match the filter will be forwarded to the wrapped log.
+/// Other records will be ignored.
+#[derive(Debug)]
+pub struct FilteredLog<T> {
+    filter: Filter,
+    log: T,
+}
+
+impl<T: Log> FilteredLog<T> {
+    /// Create a new filtered log.
+    pub fn new(filter: Filter, log: T) -> Self {
+        Self { filter, log }
+    }
+
+    /// Gets a reference to the filter.
+    pub fn filter(&self) -> &Filter {
+        &self.filter
+    }
+
+    /// Gets a mutable reference to the filter.
+    pub fn filter_mut(&mut self) -> &mut Filter {
+        &mut self.filter
+    }
+
+    /// Gets a reference to the wrapped log.
+    pub fn inner(&self) -> &T {
+        &self.log
+    }
+
+    /// Gets a mutable reference to the wrapped log.
+    pub fn inner_mut(&mut self) -> &mut T {
+        &mut self.log
+    }
+
+    /// Consumes the filtered log to take back ownership of the filter and the wrapped log.
+    pub fn into_parts(self) -> (Filter, T) {
+        (self.filter, self.log)
+    }
+}
+
+impl<T: Log> Log for FilteredLog<T> {
+    /// Determines if a log message with the specified metadata would be logged.
+    ///
+    /// For the wrapped log, this returns `true` only if both the filter and the wrapped log return `true`.
+    fn enabled(&self, metadata: &log::Metadata) -> bool {
+        self.filter.enabled(metadata) && self.log.enabled(metadata)
+    }
+
+    /// Logs the record.
+    ///
+    /// Forwards the record to the wrapped log, but only if the record matches the filter.
+    fn log(&self, record: &log::Record) {
+        if self.filter.matches(record) {
+            self.log.log(record)
+        }
+    }
+
+    /// Flushes any buffered records.
+    ///
+    /// Forwards directly to the wrapped log.
+    fn flush(&self) {
+        self.log.flush()
+    }
+}

src/filter/mod.rs → env_filter/src/lib.rs

@@ -1,31 +1,27 @@
 //! Filtering for log records.
 //!
-//! This module contains the log filtering used by `env_logger` to match records.
+//! This crate contains the log filtering used by `env_logger` to match records.
 //! You can use the `Filter` type in your own logger implementation to use the same
 //! filter parsing and matching as `env_logger`. For more details about the format
 //! for directive strings see [Enabling Logging].
 //!
-//! ## Using `env_logger` in your own logger
+//! ## Using `env_filter` in your own logger
 //!
-//! You can use `env_logger`'s filtering functionality with your own logger.
+//! You can use `env_filter`'s filtering functionality with your own logger.
 //! Call [`Builder::parse`] to parse directives from a string when constructing
 //! your logger. Call [`Filter::matches`] to check whether a record should be
 //! logged based on the parsed filters when log records are received.
 //!
 //! ```
-//! extern crate log;
-//! extern crate env_logger;
-//! use env_logger::filter::Filter;
 //! use log::{Log, Metadata, Record};
 //!
 //! struct MyLogger {
-//!     filter: Filter
+//!     filter: env_filter::Filter
 //! }
 //!
 //! impl MyLogger {
 //!     fn new() -> MyLogger {
-//!         use env_logger::filter::Builder;
-//!         let mut builder = Builder::new();
+//!         let mut builder = env_filter::Builder::new();
 //!
 //!         // Parse a directives string from an environment variable
 //!         if let Ok(ref filter) = std::env::var("MY_LOG_LEVEL") {
@@ -55,8 +51,6 @@
 //! ```
 //!
 //! [Enabling Logging]: ../index.html#enabling-logging
-//! [`Builder::parse`]: struct.Builder.html#method.parse
-//! [`Filter::matches`]: struct.Filter.html#method.matches
 
 use log::{Level, LevelFilter, Metadata, Record};
 use std::env;
@@ -71,6 +65,9 @@ mod inner;
 #[path = "string.rs"]
 mod inner;
 
+mod filtered_log;
+pub use filtered_log::FilteredLog;
+
 /// A builder for a log filter.
 ///
 /// It can be used to parse a set of directives from a string before building
@@ -79,14 +76,10 @@ mod inner;
 /// ## Example
 ///
 /// ```
-/// # #[macro_use] extern crate log;
-/// # use std::env;
-/// use env_logger::filter::Builder;
-///
-/// let mut builder = Builder::new();
+/// let mut builder = env_filter::Builder::new();
 ///
 /// // Parse a logging filter from an environment variable.
-/// if let Ok(rust_log) = env::var("RUST_LOG") {
+/// if let Ok(rust_log) = std::env::var("RUST_LOG") {
 ///     builder.parse(&rust_log);
 /// }
 ///
@@ -248,9 +241,8 @@ impl Filter {
     ///
     /// ```rust
     /// use log::LevelFilter;
-    /// use env_logger::filter::Builder;
     ///
-    /// let mut builder = Builder::new();
+    /// let mut builder = env_filter::Builder::new();
     /// builder.filter(Some("module1"), LevelFilter::Info);
     /// builder.filter(Some("module2"), LevelFilter::Error);
     ///
@@ -287,6 +279,13 @@ impl Filter {
 
         enabled(&self.directives, level, target)
     }
+
+    /// Wraps an existing [`Log`] implementation with the filter.
+    ///
+    /// The returned log forwards all records that match the filter to the wrapped [`Log`] implementation.
+    pub fn wrap_log<T: log::Log>(self, log: T) -> FilteredLog<T> {
+        FilteredLog::new(self, log)
+    }
 }
 
 impl fmt::Debug for Filter {

src/filter/regex.rs → env_filter/src/regex.rs

@@ -1,9 +1,6 @@
-extern crate regex;
-
+use regex::Regex;
 use std::fmt;
 
-use self::regex::Regex;
-
 #[derive(Debug)]
 pub struct Filter {
     inner: Regex,

env_logger/Cargo.toml

@@ -0,0 +1,67 @@
+[package]
+name = "env_logger"
+version = "0.10.1"
+description = """
+A logging implementation for `log` which is configured via an environment
+variable.
+"""
+repository = "https://github.com/rust-cli/env_logger"
+categories = ["development-tools::debugging"]
+keywords = ["logging", "log", "logger"]
+license = "MIT OR Apache-2.0"
+edition = "2021"
+rust-version = "1.60.0"  # MSRV
+include = [
+  "build.rs",
+  "src/**/*",
+  "Cargo.toml",
+  "Cargo.lock",
+  "LICENSE*",
+  "README.md",
+  "benches/**/*",
+  "examples/**/*",
+  "tests/**/*",
+]
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[package.metadata.release]
+pre-release-replacements = [
+  {file="CHANGELOG.md", search="Unreleased", replace="{{version}}", min=1},
+  {file="CHANGELOG.md", search="\\.\\.\\.HEAD", replace="...{{tag_name}}", exactly=1},
+  {file="CHANGELOG.md", search="ReleaseDate", replace="{{date}}", min=1},
+  {file="CHANGELOG.md", search="<!-- next-header -->", replace="<!-- next-header -->\n## [Unreleased] - ReleaseDate\n", exactly=1},
+  {file="CHANGELOG.md", search="<!-- next-url -->", replace="<!-- next-url -->\n[Unreleased]: https://github.com/rust-cli/env_logger/compare/{{tag_name}}...HEAD", exactly=1},
+]
+
+[features]
+default = ["auto-color", "humantime", "regex"]
+color = ["dep:termcolor"]
+auto-color = ["dep:is-terminal", "color"]
+humantime = ["dep:humantime"]
+regex = ["env_filter/regex"]
+
+[dependencies]
+env_filter = { version = "0.10.1", path = "../env_filter", default-features=false }
+log = { version = "0.4.8", features = ["std"] }
+termcolor = { version = "1.1.1", optional = true }
+humantime = { version = "2.0.0", optional = true }
+is-terminal = { version = "0.4.0", optional = true }
+
+[[test]]
+name = "regexp_filter"
+harness = false
+
+[[test]]
+name = "log-in-log"
+harness = false
+
+[[test]]
+name = "log_tls_dtors"
+harness = false
+
+[[test]]
+name = "init-twice-retains-filter"
+harness = false

env_logger/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE