make haze git checkout pick the correct branch by default

src/sources.rs

@@ -0,0 +1,51 @@
+use miette::{Context, IntoDiagnostic, Report, Result};
+use std::fs::read_to_string;
+use std::path::{Path, PathBuf};
+
+pub struct Sources {
+    #[allow(dead_code)]
+    base_dir: PathBuf,
+    server_version: u8,
+    server_branched_off: bool,
+}
+
+impl Sources {
+    pub fn new<P: AsRef<Path>>(base_dir: P) -> Result<Self> {
+        let base_dir = base_dir.as_ref();
+        let versions_source = read_to_string(base_dir.join("version.php"))
+            .into_diagnostic()
+            .wrap_err("failed to read version.php")?;
+        let version_line = versions_source
+            .lines()
+            .find(|line| line.starts_with("$OC_Version"))
+            .ok_or_else(|| Report::msg("failed to find line containing $OC_Version"))?;
+        let version_str_line = versions_source
+            .lines()
+            .find(|line| line.starts_with("$OC_VersionString"))
+            .ok_or_else(|| Report::msg("failed to find line containing $OC_VersionString"))?;
+        let (major, _) = version_line
+            .split_once('[')
+            .and_then(|(_, line)| line.split_once(','))
+            .ok_or_else(|| Report::msg("failed to find version number in line"))?;
+        let server_version = major
+            .trim()
+            .parse()
+            .into_diagnostic()
+            .wrap_err("failed to parse version number")?;
+        let server_branched_off = !version_str_line.contains("dev");
+
+        Ok(Sources {
+            base_dir: base_dir.into(),
+            server_version,
+            server_branched_off,
+        })
+    }
+
+    pub fn get_server_version_branch(&self) -> String {
+        if self.server_branched_off {
+            format!("stable{}", self.server_version)
+        } else {
+            "master".into()
+        }
+    }
+}