1 files changed, 197 insertions, 5 deletions
diff --git a/src/git_config/mod.rs b/src/git_config/mod.rs
index 9c7b2212..827446e1 100644
--- a/src/git_config/mod.rs
+++ b/src/git_config/mod.rs
@@ -1,6 +1,198 @@
-pub mod git_config;
-pub mod git_config_entry;
+mod git_config_entry;
 
-pub use crate::git_config::git_config::{GitConfig, GitConfigGet};
-pub use crate::git_config::git_config_entry::GitConfigEntry;
-pub use crate::git_config::git_config_entry::GitRemoteRepo;
+pub use git_config_entry::{GitConfigEntry, GitRemoteRepo};
+
+use regex::Regex;
+use std::collections::HashMap;
+use std::env;
+#[cfg(test)]
+use std::path::Path;
+use std::process;
+
+use lazy_static::lazy_static;
+
+pub struct GitConfig {
+    config: git2::Config,
+    config_from_env_var: HashMap<String, String>,
+    pub enabled: bool,
+    pub repo: Option<git2::Repository>,
+}
+
+impl GitConfig {
+    pub fn try_create() -> Option<Self> {
+        let repo = match std::env::current_dir() {
+            Ok(dir) => git2::Repository::discover(dir).ok(),
+            _ => None,
+        };
+        let config = match &repo {
+            Some(repo) => repo.config().ok(),
+            None => git2::Config::open_default().ok(),
+        };
+        match config {
+            Some(mut config) => {
+                let config = config.snapshot().unwrap_or_else(|err| {
+                    eprintln!("Failed to read git config: {}", err);
+                    process::exit(1)
+                });
+                Some(Self {
+                    config,
+                    config_from_env_var: parse_config_from_env_var(),
+                    repo,
+                    enabled: true,
+                })
+            }
+            None => None,
+        }
+    }
+
+    #[cfg(test)]
+    pub fn from_path(path: &Path, honor_env_var: bool) -> Self {
+        Self {
+            config: git2::Config::open(path).unwrap(),
+            config_from_env_var: if honor_env_var {
+                parse_config_from_env_var()
+            } else {
+                HashMap::new()
+            },
+            repo: None,
+            enabled: true,
+        }
+    }
+
+    pub fn get<T>(&self, key: &str) -> Option<T>
+    where
+        T: GitConfigGet,
+    {
+        if self.enabled {
+            T::git_config_get(key, self)
+        } else {
+            None
+        }
+    }
+}
+
+fn parse_config_from_env_var() -> HashMap<String, String> {
+    if let Ok(s) = env::var("GIT_CONFIG_PARAMETERS") {
+        parse_config_from_env_var_value(&s)
+    } else {
+        HashMap::new()
+    }
+}
+
+lazy_static! {
+    static ref GIT_CONFIG_PARAMETERS_REGEX: Regex =
+        Regex::new(r"'(delta\.[a-z-]+)=([^']+)'").unwrap();
+}
+
+fn parse_config_from_env_var_value(s: &str) -> HashMap<String, String> {
+    GIT_CONFIG_PARAMETERS_REGEX
+        .captures_iter(s)
+        .map(|captures| (captures[1].to_string(), captures[2].to_string()))
+        .collect()
+}
+
+pub trait GitConfigGet {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self>
+    where
+        Self: Sized;
+}
+
+impl GitConfigGet for String {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        match git_config.config_from_env_var.get(key) {
+            Some(val) => Some(val.to_string()),
+            None => git_config.config.get_string(key).ok(),
+        }
+    }
+}
+
+impl GitConfigGet for Option<String> {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        match git_config.config_from_env_var.get(key) {
+            Some(val) => Some(Some(val.to_string())),
+            None => match git_config.config.get_string(key) {
+                Ok(val) => Some(Some(val)),
+                _ => None,
+            },
+        }
+    }
+}
+
+impl GitConfigGet for bool {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        match git_config.config_from_env_var.get(key).map(|s| s.as_str()) {
+            Some("true") => Some(true),
+            Some("false") => Some(false),
+            _ => git_config.config.get_bool(key).ok(),
+        }
+    }
+}
+
+impl GitConfigGet for usize {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        if let Some(s) = git_config.config_from_env_var.get(key) {
+            if let Ok(n) = s.parse::<usize>() {
+                return Some(n);
+            }
+        }
+        match git_config.config.get_i64(key) {
+            Ok(value) => Some(value as usize),
+            _ => None,
+        }
+    }
+}
+
+impl GitConfigGet for f64 {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        if let Some(s) = git_config.config_from_env_var.get(key) {
+            if let Ok(n) = s.parse::<f64>() {
+                return Some(n);
+            }
+        }
+        match git_config.config.get_string(key) {
+            Ok(value) => value.parse::<f64>().ok(),
+            _ => None,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::parse_config_from_env_var_value;
+
+    #[test]
+    fn test_parse_config_from_env_var_value() {
+        // To generate test cases, use git -c ... with
+        // [core]
+        //     pager = env | grep GIT_CONFIG_PARAMETERS
+
+        let config = parse_config_from_env_var_value("'user.name=xxx'");
+        assert!(config.is_empty());
+
+        let config = parse_config_from_env_var_value("'delta.plus-style=green'");
+        assert_eq!(config["delta.plus-style"], "green");
+
+        let config = parse_config_from_env_var_value(
+            r##"'user.name=xxx' 'delta.hunk-header-line-number-style=red "#067a00"'"##,
+        );
+        assert_eq!(
+            config["delta.hunk-header-line-number-style"],
+            r##"red "#067a00""##
+        );
+
+        let config =
+            parse_config_from_env_var_value(r##"'user.name=xxx' 'delta.side-by-side=false'"##);
+        assert_eq!(config["delta.side-by-side"], "false");
+
+        let config = parse_config_from_env_var_value(
+            r##"'delta.plus-style=green' 'delta.side-by-side=false' 'delta.hunk-header-line-number-style=red "#067a00"'"##,
+        );
+        assert_eq!(config["delta.plus-style"], "green");
+        assert_eq!(config["delta.side-by-side"], "false");
+        assert_eq!(
+            config["delta.hunk-header-line-number-style"],
+            r##"red "#067a00""##
+        );
+    }
+}