Add support for LESSOPEN and LESSCLOSE.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Features
 - Add SystemVerilog file syntax, see #1580 (@SeanMcLoughlin)
+- Add `--preprocessor=lessopen` support, see #1597 (@eth-p) 
 
 ## Bugfixes
 

Cargo.toml

@@ -24,9 +24,12 @@ application = [
     "paging",
     "wild",
     "regex-onig",
+    "preprocessor-lessopen",
 ]
 git = ["git2"] # Support indicating git modifications
 paging = ["shell-words"] # Support applying a pager on the output
+preprocessor = []
+preprocessor-lessopen = ["preprocessor", "os_str_bytes"] # Support LESSOPEN and LESSCLOSE
 
 # You need to use one of these if you depend on bat as a library:
 regex-onig = ["syntect/regex-onig"] # Use the "oniguruma" regex engine
@@ -51,6 +54,7 @@ path_abs = { version = "0.5", default-features = false }
 clircle = "0.3"
 bugreport = "0.3"
 dirs-next = { version = "2.0.0", optional = true }
+os_str_bytes = { version = "3.0", optional = true }
 
 [dependencies.git2]
 version = "0.13"

README.md

@@ -189,6 +189,16 @@ Also, note that this will [not work](https://github.com/sharkdp/bat/issues/1145)
 The [`prettybat`](https://github.com/eth-p/bat-extras/blob/master/doc/prettybat.md) script is a wrapper that will format code and print it with `bat`.
 
 
+#### `lesspipe.sh`
+
+Starting from version `0.19.0`, `bat` has opt-in support for file preprocessing using the `LESSOPEN` and `LESSCLOSE` environment variables.
+This can be used with [lesspipe.sh](https://github.com/wofr06/lesspipe) to enable viewing of compressed files, PDFs, and much more.
+
+To enable preprocessing, you need to either pass the `--preprocessor=lessopen` argument through the command line, or add it to bat's [configuration file](https://github.com/sharkdp/bat#configuration-file).
+
+For more information on how to use `LESSOPEN` and `LESSCLOSE`, please check the [Input Preprocessor section of `man less(1)`](https://linux.die.net/man/1/less#~#Input%20Preprocessor#:~:text=You%20may%20define%20an%20%22input%20preprocessor%22%20for%20less.).
+
+
 ## Installation
 
 [![Packaging status](https://repology.org/badge/vertical-allrepos/bat-cat.svg)](https://repology.org/project/bat-cat/versions)

src/assets.rs

@@ -2,7 +2,7 @@ use std::collections::BTreeMap;
 use std::ffi::OsStr;
 use std::fs::{self, File};
 use std::io::BufReader;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use syntect::dumps::{dump_to_file, from_binary, from_reader};
 use syntect::highlighting::{Theme, ThemeSet};
@@ -13,7 +13,7 @@ use path_abs::PathAbs;
 use crate::assets_metadata::AssetsMetadata;
 use crate::bat_warning;
 use crate::error::*;
-use crate::input::{InputReader, OpenedInput, OpenedInputKind};
+use crate::input::{InputReader, OpenedInput};
 use crate::syntax_mapping::{MappingTarget, SyntaxMapping};
 
 #[derive(Debug)]
@@ -225,19 +225,15 @@ impl HighlightingAssets {
             // Get the path of the file:
             // If this was set by the metadata, that will take priority.
             // If it wasn't, it will use the real file path (if available).
-            let path_str =
-                input
-                    .metadata
-                    .user_provided_name
-                    .as_ref()
-                    .or_else(|| match input.kind {
-                        OpenedInputKind::OrdinaryFile(ref path) => Some(path),
-                        _ => None,
-                    });
-
-            if let Some(path_str) = path_str {
+            let path_str: Option<PathBuf> = input
+                .metadata
+                .user_provided_name
+                .as_ref()
+                .cloned()
+                .or_else(|| input.original_name().map(Into::<PathBuf>::into));
+
+            if let Some(ref path) = path_str {
                 // If a path was provided, we try and detect the syntax based on extension mappings.
-                let path = Path::new(path_str);
                 let absolute_path = PathAbs::new(path)
                     .ok()
                     .map(|p| p.as_path().to_path_buf())
@@ -299,7 +295,7 @@ mod tests {
     use std::io::Write;
     use tempfile::TempDir;
 
-    use crate::input::Input;
+    use crate::input::{Input, InputHandle};
 
     struct SyntaxDetectionTest<'a> {
         assets: HighlightingAssets,
@@ -328,8 +324,11 @@ mod tests {
             }
 
             let input = Input::ordinary_file(&file_path);
-            let dummy_stdin: &[u8] = &[];
-            let mut opened_input = input.open(dummy_stdin, None).unwrap();
+            let input_handle = InputHandle {
+                stdout_identifier: None,
+            };
+
+            let mut opened_input = input.open(&input_handle).unwrap();
 
             self.assets
                 .get_syntax(None, &mut opened_input, &self.syntax_mapping)
@@ -342,8 +341,10 @@ mod tests {
             let file_path = self.temp_dir.path().join(file_name);
             let input = Input::from_reader(Box::new(BufReader::new(first_line.as_bytes())))
                 .with_name(Some(&file_path));
-            let dummy_stdin: &[u8] = &[];
-            let mut opened_input = input.open(dummy_stdin, None).unwrap();
+            let input_handle = InputHandle {
+                stdout_identifier: None,
+            };
+            let mut opened_input = input.open(&input_handle).unwrap();
 
             self.assets
                 .get_syntax(None, &mut opened_input, &self.syntax_mapping)
@@ -366,8 +367,11 @@ mod tests {
         }
 
         fn syntax_for_stdin_with_content(&self, file_name: &str, content: &[u8]) -> String {
-            let input = Input::stdin().with_name(Some(file_name));
-            let mut opened_input = input.open(content, None).unwrap();
+            let input = Input::stdin_with_contents(content).with_name(Some(file_name));
+            let input_handle = InputHandle {
+                stdout_identifier: None,
+            };
+            let mut opened_input = input.open(&input_handle).unwrap();
 
             self.assets
                 .get_syntax(None, &mut opened_input, &self.syntax_mapping)
@@ -523,8 +527,10 @@ mod tests {
         symlink(&file_path, &file_path_symlink).expect("creation of symbolic link succeeds");
 
         let input = Input::ordinary_file(&file_path_symlink);
-        let dummy_stdin: &[u8] = &[];
-        let mut opened_input = input.open(dummy_stdin, None).unwrap();
+        let input_handle = InputHandle {
+            stdout_identifier: None,
+        };
+        let mut opened_input = input.open(&input_handle).unwrap();
 
         assert_eq!(
             test.assets

src/bin/bat/clap_app.rs

@@ -148,6 +148,26 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
                 )
     }
 
+    #[cfg(feature = "preprocessor")]
+    {
+        let mut preprocessors: Vec<&'static str> = vec!["none"];
+
+        #[cfg(feature = "preprocessor-lessopen")]
+        preprocessors.push("lessopen");
+
+        app = app.arg(
+            Arg::with_name("preprocessor")
+                .long("preprocessor")
+                .overrides_with("preprocessor")
+                .takes_value(true)
+                .value_name("preprocessor")
+                .possible_values(&preprocessors)
+                .default_value("none")
+                .hide_default_value(true)
+                .help("Specify the preprocessor to use on input files."),
+        )
+    }
+
     app = app.arg(
         Arg::with_name("tabs")
             .long("tabs")

src/bin/bat/config.rs

@@ -55,6 +55,10 @@ pub fn generate_config_file() -> bat::error::Result<()> {
 # terminal emulators (like tmux, by default):
 #--italic-text=always
 
+# Uncomment the following line to enable LESSOPEN/LESSCLOSE preprocessing.
+# You can disable preprocessing on the command line with `--preprocessor=none`.
+#--preprocessor=lessopen
+
 # Uncomment the following line to disable automatic paging:
 #--paging=never
 

src/bin/bat/main.rs

@@ -27,6 +27,9 @@ use clap::crate_version;
 use directories::PROJECT_DIRS;
 use globset::GlobMatcher;
 
+#[cfg(feature = "preprocessor")]
+use bat::preprocessor::Preprocessor;
+
 use bat::{
     assets::HighlightingAssets,
     config::Config,
@@ -215,9 +218,27 @@ pub fn list_themes(cfg: &Config) -> Result<()> {
     Ok(())
 }
 
-fn run_controller(inputs: Vec<Input>, config: &Config) -> Result<bool> {
+#[cfg_attr(not(feature = "preprocessor"), allow(unused_variables))]
+fn run_controller<'a>(inputs: Vec<Input<'a>>, config: &'a Config, app: &App) -> Result<bool> {
     let assets = assets_from_cache_or_binary()?;
     let controller = Controller::new(&config, &assets);
+
+    #[cfg(feature = "preprocessor")]
+    let mut preprocessor: Option<Preprocessor> = None;
+
+    #[cfg(feature = "preprocessor-lessopen")]
+    if app.matches.value_of("preprocessor") == Some("lessopen") {
+        preprocessor = std::env::var("LESSOPEN").ok().and_then(|lessopen| {
+            bat::preprocessor::lessopen(lessopen, std::env::var("LESSCLOSE").ok())
+        });
+    }
+
+    #[cfg(feature = "preprocessor")]
+    let controller = match preprocessor {
+        Some(preprocessor) => controller.with_preprocessor(preprocessor),
+        None => controller,
+    };
+
     controller.run(inputs)
 }
 
@@ -271,7 +292,7 @@ fn run() -> Result<bool> {
                 let inputs = vec![Input::ordinary_file("cache")];
                 let config = app.config(&inputs)?;
 
-                run_controller(inputs, &config)
+                run_controller(inputs, &config, &app)
             }
         }
         _ => {
@@ -286,7 +307,7 @@ fn run() -> Result<bool> {
                     paging_mode: PagingMode::QuitIfOneScreen,
                     ..Default::default()
                 };
-                run_controller(inputs, &plain_config)
+                run_controller(inputs, &plain_config, &app)
             } else if app.matches.is_present("list-themes") {
                 list_themes(&config)?;
                 Ok(true)
@@ -303,7 +324,7 @@ fn run() -> Result<bool> {
                 writeln!(io::stdout(), "{}", cache_dir())?;
                 Ok(true)
             } else {
-                run_controller(inputs, &config)
+                run_controller(inputs, &config, &app)
             }
         }
     }