Split `syntax_mapping/builtin.rs`

3 files changed, 103 insertions, 97 deletions

diff --git a/build/syntax_mapping.rs b/build/syntax_mapping.rs
index 0b4b5cd4..78a7805c 100644
--- a/build/syntax_mapping.rs
+++ b/build/syntax_mapping.rs
@@ -173,7 +173,7 @@ impl MappingList {
         let len = array_items.len();
 
         format!(
-            "static BUILTIN_MAPPINGS: [(Lazy<Option<GlobMatcher>>, MappingTarget); {len}] = [\n{items}\n];",
+            "pub(crate) static BUILTIN_MAPPINGS: [(Lazy<Option<GlobMatcher>>, MappingTarget); {len}] = [\n{items}\n];",
             items = array_items.join(",\n")
         )
     }
diff --git a/src/syntax_mapping.rs b/src/syntax_mapping.rs
index 8cc009a4..73b18dcb 100644
--- a/src/syntax_mapping.rs
+++ b/src/syntax_mapping.rs
@@ -1,96 +1,20 @@
-use std::{env, path::Path};
+use std::path::Path;
+
+use globset::{Candidate, GlobBuilder, GlobMatcher};
 
 use crate::error::Result;
 use ignored_suffixes::IgnoredSuffixes;
 
-use globset::{Candidate, GlobBuilder, GlobMatcher};
-use once_cell::sync::Lazy;
-
+mod builtin;
 pub mod ignored_suffixes;
 
-// Static syntax mappings generated from /src/syntax_mapping/builtins/ by the
-// build script (/build/syntax_mapping.rs).
-include!(concat!(
-    env!("OUT_DIR"),
-    "/codegen_static_syntax_mappings.rs"
-));
-
-// The defined matcher strings are analysed at compile time and converted into
-// lazily-compiled `GlobMatcher`s. This is so that the string searches are moved
-// from run time to compile time, thus improving startup performance.
-//
-// To any future maintainer (including possibly myself) wondering why there is
-// not a `BuiltinMatcher` enum that looks like this:
-//
-// ```
-// enum BuiltinMatcher {
-//     Fixed(&'static str),
-//     Dynamic(Lazy<Option<String>>),
-// }
-// ```
-//
-// Because there was. I tried it and threw it out.
-//
-// Naively looking at the problem from a distance, this may seem like a good
-// design (strongly typed etc. etc.). It would also save on compiled size by
-// extracting out common behaviour into functions. But while actually
-// implementing the lazy matcher compilation logic, I realised that it's most
-// convenient for `BUILTIN_MAPPINGS` to have the following type:
-//
-// `[(Lazy<Option<GlobMatcher>>, MappingTarget); N]`
-//
-// The benefit for this is that operations like listing all builtin mappings
-// would be effectively memoised. The caller would not have to compile another
-// `GlobMatcher` for rules that they have previously visited.
-//
-// Unfortunately, this means we are going to have to store a distinct closure
-// for each rule anyway, which makes a `BuiltinMatcher` enum a pointless layer
-// of indirection.
-//
-// In the current implementation, the closure within each generated rule simply
-// calls either `build_matcher_fixed` or `build_matcher_dynamic`, depending on
-// whether the defined matcher contains dynamic segments or not.
-
-/// Compile a fixed glob string into a glob matcher.
-///
-/// A failure to compile is a fatal error.
-///
-/// Used internally by `Lazy<GlobMatcher>`'s lazy evaluation closure.
-fn build_matcher_fixed(from: &str) -> GlobMatcher {
-    make_glob_matcher(from).expect("A builtin fixed glob matcher failed to compile")
-}
-
-/// Join a list of matcher segments to create a glob string, replacing all
-/// environment variables, then compile to a glob matcher.
-///
-/// Returns `None` if any replacement fails, or if the joined glob string fails
-/// to compile.
-///
-/// Used internally by `Lazy<GlobMatcher>`'s lazy evaluation closure.
-fn build_matcher_dynamic(segs: &[MatcherSegment]) -> Option<GlobMatcher> {
-    // join segments
-    let mut buf = String::new();
-    for seg in segs {
-        match seg {
-            MatcherSegment::Text(s) => buf.push_str(s),
-            MatcherSegment::Env(var) => {
-                let replaced = env::var(var).ok()?;
-                buf.push_str(&replaced);
-            }
-        }
-    }
-    // compile glob matcher
-    let matcher = make_glob_matcher(&buf).ok()?;
-    Some(matcher)
-}
-
-/// A segment of a dynamic builtin matcher.
-///
-/// Used internally by `Lazy<GlobMatcher>`'s lazy evaluation closure.
-#[derive(Clone, Debug)]
-enum MatcherSegment {
-    Text(&'static str),
-    Env(&'static str),
+fn make_glob_matcher(from: &str) -> Result<GlobMatcher> {
+    let matcher = GlobBuilder::new(from)
+        .case_insensitive(true)
+        .literal_separator(true)
+        .build()?
+        .compile_matcher();
+    Ok(matcher)
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -113,15 +37,6 @@ pub enum MappingTarget<'a> {
     MapExtensionToUnknown,
 }
 
-fn make_glob_matcher(from: &str) -> Result<GlobMatcher> {
-    let matcher = GlobBuilder::new(from)
-        .case_insensitive(true)
-        .literal_separator(true)
-        .build()?
-        .compile_matcher();
-    Ok(matcher)
-}
-
 #[derive(Debug, Clone, Default)]
 pub struct SyntaxMapping<'a> {
     mappings: Vec<(GlobMatcher, MappingTarget<'a>)>,
diff --git a/src/syntax_mapping/builtin.rs b/src/syntax_mapping/builtin.rs
new file mode 100644
index 00000000..7efff8bc
--- /dev/null
+++ b/src/syntax_mapping/builtin.rs
@@ -0,0 +1,91 @@
+use std::env;
+
+use globset::GlobMatcher;
+use once_cell::sync::Lazy;
+
+use crate::syntax_mapping::{make_glob_matcher, MappingTarget};
+
+// Static syntax mappings generated from /src/syntax_mapping/builtins/ by the
+// build script (/build/syntax_mapping.rs).
+include!(concat!(
+    env!("OUT_DIR"),
+    "/codegen_static_syntax_mappings.rs"
+));
+
+// The defined matcher strings are analysed at compile time and converted into
+// lazily-compiled `GlobMatcher`s. This is so that the string searches are moved
+// from run time to compile time, thus improving startup performance.
+//
+// To any future maintainer (including possibly myself) wondering why there is
+// not a `BuiltinMatcher` enum that looks like this:
+//
+// ```
+// enum BuiltinMatcher {
+//     Fixed(&'static str),
+//     Dynamic(Lazy<Option<String>>),
+// }
+// ```
+//
+// Because there was. I tried it and threw it out.
+//
+// Naively looking at the problem from a distance, this may seem like a good
+// design (strongly typed etc. etc.). It would also save on compiled size by
+// extracting out common behaviour into functions. But while actually
+// implementing the lazy matcher compilation logic, I realised that it's most
+// convenient for `BUILTIN_MAPPINGS` to have the following type:
+//
+// `[(Lazy<Option<GlobMatcher>>, MappingTarget); N]`
+//
+// The benefit for this is that operations like listing all builtin mappings
+// would be effectively memoised. The caller would not have to compile another
+// `GlobMatcher` for rules that they have previously visited.
+//
+// Unfortunately, this means we are going to have to store a distinct closure
+// for each rule anyway, which makes a `BuiltinMatcher` enum a pointless layer
+// of indirection.
+//
+// In the current implementation, the closure within each generated rule simply
+// calls either `build_matcher_fixed` or `build_matcher_dynamic`, depending on
+// whether the defined matcher contains dynamic segments or not.
+
+/// Compile a fixed glob string into a glob matcher.
+///
+/// A failure to compile is a fatal error.
+///
+/// Used internally by `Lazy<GlobMatcher>`'s lazy evaluation closure.
+fn build_matcher_fixed(from: &str) -> GlobMatcher {
+    make_glob_matcher(from).expect("A builtin fixed glob matcher failed to compile")
+}
+
+/// Join a list of matcher segments to create a glob string, replacing all
+/// environment variables, then compile to a glob matcher.
+///
+/// Returns `None` if any replacement fails, or if the joined glob string fails
+/// to compile.
+///
+/// Used internally by `Lazy<GlobMatcher>`'s lazy evaluation closure.
+fn build_matcher_dynamic(segs: &[MatcherSegment]) -> Option<GlobMatcher> {
+    // join segments
+    let mut buf = String::new();
+    for seg in segs {
+        match seg {
+            MatcherSegment::Text(s) => buf.push_str(s),
+            MatcherSegment::Env(var) => {
+                let replaced = env::var(var).ok()?;
+                buf.push_str(&replaced);
+            }
+        }
+    }
+    // compile glob matcher
+    let matcher = make_glob_matcher(&buf).ok()?;
+    Some(matcher)
+}
+
+/// A segment of a dynamic builtin matcher.
+///
+/// Used internally by `Lazy<GlobMatcher>`'s lazy evaluation closure.
+#[derive(Clone, Debug)]
+enum MatcherSegment {
+    Text(&'static str),
+    Env(&'static str),
+}