read themes from bat's cache as well

3 files changed, 85 insertions, 3 deletions

diff --git a/src/bat/assets.rs b/src/bat/assets.rs
index b8bd4561..f436fef1 100644
--- a/src/bat/assets.rs
+++ b/src/bat/assets.rs
@@ -1,14 +1,19 @@
 // Based on code from https://github.com/sharkdp/bat a1b9334a44a2c652f52dddaa83dbacba57372468
 // See src/bat/LICENSE
 
-use std::io::{self, Write};
+use std::fs::File;
+use std::io::{self, BufReader, Write};
+use std::path::PathBuf;
 
 use ansi_term::Colour::Green;
 use ansi_term::Style;
-use syntect::dumps::from_binary;
+use syntect::dumps::{from_binary, from_reader};
 use syntect::highlighting::ThemeSet;
 use syntect::parsing::SyntaxSet;
 
+use crate::bat::dirs::PROJECT_DIRS;
+use crate::errors::*;
+
 pub struct HighlightingAssets {
     pub syntax_set: SyntaxSet,
     pub theme_set: ThemeSet,
@@ -16,7 +21,7 @@ pub struct HighlightingAssets {
 
 impl HighlightingAssets {
     pub fn new() -> Self {
-        Self::from_binary()
+        Self::from_cache().unwrap_or_else(|_| Self::from_binary())
     }
 
     fn get_integrated_syntaxset() -> SyntaxSet {
@@ -27,6 +32,32 @@ impl HighlightingAssets {
         from_binary(include_bytes!("../../assets/themes.bin"))
     }
 
+    fn from_cache() -> Result<Self> {
+        let theme_set_path = theme_set_path();
+        let syntax_set_file = File::open(&syntax_set_path()).chain_err(|| {
+            format!(
+                "Could not load cached syntax set '{}'",
+                syntax_set_path().to_string_lossy()
+            )
+        })?;
+        let syntax_set: SyntaxSet = from_reader(BufReader::new(syntax_set_file))
+            .chain_err(|| "Could not parse cached syntax set")?;
+
+        let theme_set_file = File::open(&theme_set_path).chain_err(|| {
+            format!(
+                "Could not load cached theme set '{}'",
+                theme_set_path.to_string_lossy()
+            )
+        })?;
+        let theme_set: ThemeSet = from_reader(BufReader::new(theme_set_file))
+            .chain_err(|| "Could not parse cached theme set")?;
+
+        Ok(HighlightingAssets {
+            syntax_set,
+            theme_set,
+        })
+    }
+
     fn from_binary() -> Self {
         let syntax_set = Self::get_integrated_syntaxset();
         let theme_set = Self::get_integrated_themeset();
@@ -38,6 +69,14 @@ impl HighlightingAssets {
     }
 }
 
+fn theme_set_path() -> PathBuf {
+    PROJECT_DIRS.cache_dir().join("themes.bin")
+}
+
+fn syntax_set_path() -> PathBuf {
+    PROJECT_DIRS.cache_dir().join("syntaxes.bin")
+}
+
 pub fn list_languages() -> std::io::Result<()> {
     let assets = HighlightingAssets::new();
     let mut languages = assets
diff --git a/src/bat/dirs.rs b/src/bat/dirs.rs
new file mode 100644
index 00000000..26c49b20
--- /dev/null
+++ b/src/bat/dirs.rs
@@ -0,0 +1,42 @@
+// Based on code from https://github.com/sharkdp/bat e981e974076a926a38f124b7d8746de2ca5f0a28
+// See src/bat/LICENSE
+
+use dirs as dirs_rs;
+use lazy_static::lazy_static;
+use std::path::{Path, PathBuf};
+
+#[cfg(target_os = "macos")]
+use std::env;
+
+/// Wrapper for 'dirs' that treats MacOS more like Linux, by following the XDG specification.
+/// This means that the `XDG_CACHE_HOME` and `XDG_CONFIG_HOME` environment variables are
+/// checked first. The fallback directories are `~/.cache/bat` and `~/.config/bat`, respectively.
+pub struct BatProjectDirs {
+    cache_dir: PathBuf,
+}
+
+impl BatProjectDirs {
+    fn new() -> Option<BatProjectDirs> {
+        #[cfg(target_os = "macos")]
+        let cache_dir_op = env::var_os("XDG_CACHE_HOME")
+            .map(PathBuf::from)
+            .filter(|p| p.is_absolute())
+            .or_else(|| dirs_rs::home_dir().map(|d| d.join(".cache")));
+
+        #[cfg(not(target_os = "macos"))]
+        let cache_dir_op = dirs_rs::cache_dir();
+
+        let cache_dir = cache_dir_op.map(|d| d.join("bat"))?;
+
+        Some(BatProjectDirs { cache_dir })
+    }
+
+    pub fn cache_dir(&self) -> &Path {
+        &self.cache_dir
+    }
+}
+
+lazy_static! {
+    pub static ref PROJECT_DIRS: BatProjectDirs =
+        BatProjectDirs::new().expect("Could not get home directory");
+}
diff --git a/src/bat/mod.rs b/src/bat/mod.rs
index e26ac304..88673f26 100644
--- a/src/bat/mod.rs
+++ b/src/bat/mod.rs
@@ -1,2 +1,3 @@
 pub mod assets;
+pub mod dirs;
 pub mod output;