Extract some private submodules from 'bat::assets' (#1850)

src/assets/serialized_syntax_set.rs

@@ -0,0 +1,27 @@
+use std::path::PathBuf;
+
+use syntect::parsing::SyntaxSet;
+
+use super::*;
+
+/// A SyntaxSet in serialized form, i.e. bincoded and flate2 compressed.
+/// We keep it in this format since we want to load it lazily.
+#[derive(Debug)]
+pub enum SerializedSyntaxSet {
+    /// The data comes from a user-generated cache file.
+    FromFile(PathBuf),
+
+    /// The data to use is embedded into the bat binary.
+    FromBinary(&'static [u8]),
+}
+
+impl SerializedSyntaxSet {
+    pub fn deserialize(&self) -> Result<SyntaxSet> {
+        match self {
+            SerializedSyntaxSet::FromBinary(data) => Ok(from_binary(data, COMPRESS_SYNTAXES)),
+            SerializedSyntaxSet::FromFile(ref path) => {
+                asset_from_cache(path, "syntax set", COMPRESS_SYNTAXES)
+            }
+        }
+    }
+}