Add Scouter subproject. This takes a file and detects what project it might belong to, traversing up the hierarchy until it encounters a supported project type.

Because projects can be nested, the Scouter is actually an iterator. For the purposes of Shenlong though generally only the first value will be used.

scouter/Cargo.lock

@@ -0,0 +1,4 @@
+[[package]]
+name = "scouter"
+version = "0.1.0"
+

scouter/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "scouter"
+version = "0.1.0"
+authors = ["Adrian Malacoda <adrian.malacoda@monarch-pass.net>"]
+edition = "2018"
+
+[dependencies]

scouter/src/lib.rs

@@ -0,0 +1,85 @@
+use std::path::{Path, PathBuf};
+
+#[derive(Debug, PartialEq)]
+pub enum ProjectType {
+    Maven,
+    Npm,
+    Cargo
+}
+
+impl ProjectType {
+    fn detect<P: AsRef<Path>>(path: P) -> Option<ProjectType> {
+        let project_path: PathBuf = path.as_ref().into();
+        if project_path.join("pom.xml").is_file() {
+            return Some(ProjectType::Maven);
+        } else if project_path.join("package.json").is_file() {
+            return Some(ProjectType::Npm);
+        } else if project_path.join("Cargo.toml").is_file() {
+            return Some(ProjectType::Cargo);
+        }
+        
+        None
+    }
+}
+
+#[derive(Debug)]
+pub struct Project {
+    pub project_type: ProjectType,
+    path: PathBuf
+}
+
+impl Project {
+    fn path(&self) -> &Path {
+        &self.path
+    }
+}
+
+pub struct Scouter {
+    search_path: PathBuf
+}
+
+impl Scouter {
+    pub fn new<P: AsRef<Path>>(path: P) -> Scouter {
+        let mut search_path: PathBuf = path.as_ref().into();
+        if !search_path.is_dir() {
+            search_path.pop();
+        }
+        
+        Scouter {
+            search_path: search_path
+        }
+    }
+}
+
+impl Iterator for Scouter {
+    type Item = Project;
+    
+    fn next(&mut self) -> Option<Self::Item> {
+        loop {
+            let project_type = ProjectType::detect(&self.search_path);
+            if project_type.is_some()
+            {
+                return project_type.map(|project_type| Project {
+                    project_type: project_type,
+                    path: self.search_path.to_owned()
+                });
+            }
+            
+            if !self.search_path.pop()
+            {
+                return None;
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::{ProjectType, Scouter};
+    
+    #[test]
+    fn test_scouter() {
+        let mut scouter = Scouter::new(file!());
+        assert_eq!(ProjectType::Cargo, scouter.next().unwrap().project_type);
+    }
+}