Add helper to get the branch which must be checked out before any action takes place

libimagstorestdhook/src/vcs/git/config.rs

@@ -1,5 +1,11 @@
 use toml::Value;
 
+use libimagerror::into::IntoError;
+
+use vcs::git::error::GitHookErrorKind as GHEK;
+use vcs::git::error::MapErrInto;
+use vcs::git::result::Result;
+
 use vcs::git::action::StoreAction;
 
 pub fn commit_interactive(config: &Value) -> bool {
@@ -32,3 +38,23 @@ pub fn abort_on_repo_init_err(cfg: Option<&Value>) -> bool {
     .unwrap_or(false)
 }
 
+pub fn ensure_branch(cfg: Option<&Value>) -> Result<Option<String>> {
+    match cfg {
+        Some(cfg) => {
+            match cfg.lookup("ensure_branch") {
+                Some(&Value::String(ref s)) => Ok(Some(s.clone())),
+                Some(_) => {
+                    warn!("Configuration error, 'ensure_branch' must be a String.");
+                    Err(GHEK::ConfigTypeError.into_error())
+                        .map_err_into(GHEK::ConfigTypeError)
+                },
+                None => {
+                    debug!("No key `ensure_branch'");
+                    Ok(None)
+                },
+            }
+        },
+        None => Ok(None),
+    }
+}
+