Strip dependencies of bat-as-a-library

Cargo.toml

@@ -15,24 +15,41 @@ exclude = [
 build = "build.rs"
 edition = '2018'
 
+[features]
+default = ["application"]
+# Feature required for bat the application. Should be disabled when depending on
+# bat as a library.
+application = [
+    "atty",
+    "clap",
+    "dirs",
+    "git",
+    "lazy_static",
+    "liquid",
+    "paging",
+    "wild",
+]
+git = ["git2"] # Support indicating git modifications
+paging = ["shell-words"] # Support applying a pager on the output
+
 [dependencies]
-atty = "0.2.14"
+atty = { version = "0.2.14", optional = true }
 ansi_term = "^0.12.1"
 ansi_colours = "^1.0"
 console = "0.10"
-dirs = "2.0"
-lazy_static = "1.4"
-wild = "2.0"
+dirs = { version = "2.0", optional = true }
+lazy_static = { version = "1.4", optional = true }
+wild = { version = "2.0", optional = true }
 content_inspector = "0.2.4"
 encoding = "0.2"
-shell-words = "0.1.0"
+shell-words = { version = "0.1.0", optional = true }
 unicode-width = "0.1.7"
 globset = "0.4"
 
 [dependencies.git2]
 version = "0.13"
+optional = true
 default-features = false
-features = []
 
 [dependencies.syntect]
 version = "3.3.0"
@@ -41,22 +58,22 @@ features = ["parsing", "yaml-load", "dump-load", "dump-create"]
 
 [dependencies.clap]
 version = "2.33"
+optional = true
 default-features = false
 features = ["suggestions", "color", "wrap_help"]
 
 [dependencies.error-chain]
 version = "0.12"
 default-features = false
-features = []
 
 [dev-dependencies]
 tempdir = "0.3"
 assert_cmd = "0.12.0"
 
 [build-dependencies]
-clap = "2.33"
-liquid = "0.20"
-lazy_static = "1.4"
+clap = { version = "2.33", optional = true }
+liquid = { version = "0.20", optional = true }
+lazy_static = { version = "1.4", optional = true }
 
 [profile.release]
 lto = true

build.rs

@@ -1,38 +1,42 @@
 // TODO: Re-enable generation of shell completion files (below) when clap 3 is out.
 // For more details, see https://github.com/sharkdp/bat/issues/372
 
-#[macro_use]
-extern crate lazy_static;
-extern crate liquid;
-
-use std::error::Error;
-use std::fs;
-use std::path::Path;
-
-// Read environment variables.
-lazy_static! {
-    pub static ref PROJECT_NAME: &'static str = option_env!("PROJECT_NAME").unwrap_or("bat");
-    pub static ref PROJECT_VERSION: &'static str = option_env!("CARGO_PKG_VERSION").unwrap();
-    pub static ref EXECUTABLE_NAME: &'static str = option_env!("PROJECT_EXECUTABLE")
-        .or(option_env!("PROJECT_NAME"))
-        .unwrap_or("bat");
-}
-
-/// Generates a file from a liquid template.
-fn template(
-    variables: &liquid::Object,
-    in_file: &str,
-    out_file: impl AsRef<Path>,
-) -> Result<(), Box<dyn Error>> {
-    let template = liquid::ParserBuilder::with_stdlib()
-        .build()?
-        .parse(&fs::read_to_string(in_file)?)?;
-
-    fs::write(out_file, template.render(variables)?)?;
-    Ok(())
-}
+// For bat-as-a-library, no build script is required. The build script is for
+// the manpage and completions, which are only relevant to the bat application.
+#[cfg(not(feature = "application"))]
+fn main() {}
+
+#[cfg(feature = "application")]
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    use std::error::Error;
+    use std::fs;
+    use std::path::Path;
+
+    use lazy_static::lazy_static;
+
+    // Read environment variables.
+    lazy_static! {
+        static ref PROJECT_NAME: &'static str = option_env!("PROJECT_NAME").unwrap_or("bat");
+        static ref PROJECT_VERSION: &'static str = option_env!("CARGO_PKG_VERSION").unwrap();
+        static ref EXECUTABLE_NAME: &'static str = option_env!("PROJECT_EXECUTABLE")
+            .or(option_env!("PROJECT_NAME"))
+            .unwrap_or("bat");
+    }
+
+    /// Generates a file from a liquid template.
+    fn template(
+        variables: &liquid::Object,
+        in_file: &str,
+        out_file: impl AsRef<Path>,
+    ) -> Result<(), Box<dyn Error>> {
+        let template = liquid::ParserBuilder::with_stdlib()
+            .build()?
+            .parse(&fs::read_to_string(in_file)?)?;
+
+        fs::write(out_file, template.render(variables)?)?;
+        Ok(())
+    }
 
-fn main() -> Result<(), Box<dyn Error>> {
     let variables = liquid::object!({
         "PROJECT_NAME": PROJECT_NAME.to_owned(),
         "PROJECT_EXECUTABLE": EXECUTABLE_NAME.to_owned(),

ci/script.bash

@@ -12,3 +12,9 @@ if [[ $TARGET != arm-unknown-linux-gnueabihf ]] && [[ $TARGET != aarch64-unknown
     # Run 'bat' on its own source code and the README
     cargo run --target "$TARGET" -- src/bin/bat/main.rs README.md --paging=never
 fi
+
+# Check bat-as-a-library, which has a smaller set of dependencies
+cargo check --target "$TARGET" --verbose --lib --no-default-features
+cargo check --target "$TARGET" --verbose --lib --no-default-features --features git
+cargo check --target "$TARGET" --verbose --lib --no-default-features --features paging
+cargo check --target "$TARGET" --verbose --lib --no-default-features --features git,paging

src/bin/bat/app.rs

@@ -9,13 +9,9 @@ use crate::{
     config::{get_args_from_config_file, get_args_from_env_var},
 };
 use clap::ArgMatches;
-use wild;
 
 use console::Term;
 
-#[cfg(windows)]
-use ansi_term;
-
 use bat::{
     config::{
         Config, HighlightedLineRanges, InputFile, LineRange, LineRanges, MappingTarget, OutputWrap,

src/bin/bat/clap_app.rs

@@ -1,4 +1,4 @@
-use clap::{App as ClapApp, AppSettings, Arg, ArgGroup, SubCommand};
+use clap::{crate_name, crate_version, App as ClapApp, AppSettings, Arg, ArgGroup, SubCommand};
 use std::path::Path;
 
 pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {

src/bin/bat/config.rs

@@ -4,8 +4,6 @@ use std::fs;
 use std::io::{self, Write};
 use std::path::PathBuf;
 
-use shell_words;
-
 use crate::directories::PROJECT_DIRS;
 
 pub fn config_file() -> PathBuf {

src/bin/bat/directories.rs

@@ -1,7 +1,6 @@
 use std::env;
 use std::path::{Path, PathBuf};
 
-use dirs;
 use lazy_static::lazy_static;
 
 /// Wrapper for 'dirs' that treats MacOS more like Linux, by following the XDG specification.

src/bin/bat/main.rs

@@ -1,11 +1,6 @@
 // `error_chain!` can recurse deeply
 #![recursion_limit = "1024"]
 
-#[macro_use]
-extern crate clap;
-
-extern crate dirs as dirs_rs;
-
 mod app;
 mod assets;
 mod clap_app;

src/config.rs

@@ -5,12 +5,14 @@ pub use crate::syntax_mapping::{MappingTarget, SyntaxMapping};
 pub use crate::wrap::OutputWrap;
 
 #[derive(Debug, Clone, Copy, PartialEq)]
+#[cfg(feature = "paging")]
 pub enum PagingMode {
     Always,
     QuitIfOneScreen,
     Never,
 }
 
+#[cfg(feature = "paging")]
 impl Default for PagingMode {
     fn default() -> Self {
         PagingMode::Never
@@ -51,6 +53,7 @@ pub struct Config<'a> {
     pub output_wrap: OutputWrap,
 
     /// Pager or STDOUT
+    #[cfg(feature = "paging")]
     pub paging_mode: PagingMode,
 
     /// Specifies the lines that should be printed

src/controller.rs

@@ -1,8 +1,9 @@
 use std::io::{self, Write};
-use std::path::Path;
 
 use crate::assets::HighlightingAssets;
-use crate::config::{Config, PagingMode};
+use crate::config::Config;
+#[cfg(feature = "paging")]
+use crate::config::PagingMode;
 use crate::errors::*;
 use crate::inputfile::{InputFile, InputFileReader};
 use crate::line_range::{LineRanges, RangeCheckResult};
@@ -24,22 +25,34 @@ impl<'b> Controller<'b> {
     }
 
     pub fn run_with_error_handler(&self, handle_error: impl Fn(&Error)) -> Result<bool> {
-        // Do not launch the pager if NONE of the input files exist
-        let mut paging_mode = self.config.paging_mode;
-        if self.config.paging_mode != PagingMode::Never {
-            let call_pager = self.config.files.iter().any(|file| {
-                if let InputFile::Ordinary(path) = file {
-                    return Path::new(path).exists();
-                } else {
-                    return true;
+        let mut output_type;
+
+        #[cfg(feature = "paging")]
+        {
+            use std::path::Path;
+
+            // Do not launch the pager if NONE of the input files exist
+            let mut paging_mode = self.config.paging_mode;
+            if self.config.paging_mode != PagingMode::Never {
+                let call_pager = self.config.files.iter().any(|file| {
+                    if let InputFile::Ordinary(path) = file {
+                        return Path::new(path).exists();
+                    } else {
+                        return true;
+                    }
+                });
+                if !call_pager {
+                    paging_mode = PagingMode::Never;
                 }
-            });
-            if !call_pager {
-                paging_mode = PagingMode::Never;
             }
+            output_type = OutputType::from_mode(paging_mode, self.config.pager)?;
+        }
+
+        #[cfg(not(feature = "paging"))]
+        {
+            output_type = OutputType::stdout();
         }
 
-        let mut output_type = OutputType::from_mode(paging_mode, self.config.pager)?;
         let writer = output_type.handle()?;
         let mut no_errors: bool = true;
 

src/decorations.rs

@@ -1,3 +1,4 @@
+#[cfg(feature = "git")]
 use crate::diff::LineChange;
 use crate::printer::{Colors, InteractivePrinter};
 use ansi_term::Style;
@@ -68,6 +69,7 @@ impl Decoration for LineNumberDecoration {
     }
 }
 
+#[cfg(feature = "git")]
 pub struct LineChangesDecoration {
     cached_none: DecorationText,
     cached_added: DecorationText,
@@ -76,6 +78,7 @@ pub struct LineChangesDecoration {
     cached_modified: DecorationText,
 }
 
+#[cfg(feature = "git")]
 impl LineChangesDecoration {
     #[inline]
     fn generate_cached(style: Style, text: &str) -> DecorationText {
@@ -96,6 +99,7 @@ impl LineChangesDecoration {
     }
 }
 
+#[cfg(feature = "git")]
 impl Decoration for LineChangesDecoration {
     fn generate(
         &self,

src/diff.rs

@@ -1,3 +1,5 @@
+#![cfg(feature = "git")]
+
 use std::collections::HashMap;
 use std::ffi::OsStr;
 use std::fs;

src/errors.rs

@@ -2,7 +2,7 @@ use error_chain::error_chain;
 
 error_chain! {
     foreign_links {
-        Clap(::clap::Error);
+        Clap(::clap::Error) #[cfg(feature = "application")];
         Io(::std::io::Error);
         SyntectError(::syntect::LoadingError);
         ParseIntError(::std::num::ParseIntError);

src/less.rs

@@ -1,3 +1,5 @@
+#![cfg(feature = "paging")]
+
 use std::process::Command;
 
 pub fn retrieve_less_version() -> Option<usize> {

src/lib.rs

@@ -1,17 +1,6 @@
 // `error_chain!` can recurse deeply
 #![recursion_limit = "1024"]
 
-extern crate ansi_term;
-extern crate atty;
-extern crate console;
-extern crate content_inspector;
-extern crate dirs as dirs_rs;
-extern crate encoding;
-extern crate git2;
-extern crate shell_words;
-extern crate syntect;
-extern crate wild;
-
 pub(crate) mod assets;
 pub mod config;
 pub(crate) mod controller;