add support for parsing Maven project information (using effective pom)

scouter/src/lib.rs

@@ -1,4 +1,5 @@
 use std::path::{Path, PathBuf};
+use std::process::Command;
 
 #[derive(Debug, PartialEq)]
 pub enum ProjectType {
@@ -35,9 +36,9 @@ impl Project {
     
     pub fn info(&self) -> ProjectInfo {
         match self.project_type {
-            ProjectType::Maven => ProjectInfo {
-                name: "placeholder".into(),
-                version: "placeholder".into()
+            ProjectType::Maven => {
+                let effective_pom = self.read_effective_pom();
+                ProjectInfo::from_pom(&effective_pom)
             },
             ProjectType::Npm => ProjectInfo {
                 name: "placeholder".into(),
@@ -53,6 +54,21 @@ impl Project {
             .exec()
             .expect("metadata call failed")
     }
+    
+    fn read_effective_pom(&self) -> sxd_document::Package {
+        let full_output = std::str::from_utf8(&Command::new("mvn")
+            .arg("help:effective-pom")
+            .current_dir(&self.path)
+            .output()
+            .expect("failed to generate effective pom")
+            .stdout).expect("failed to generate string from output").to_owned();
+        let xml = full_output.get(
+            full_output.find("<?xml").expect("failed to find start of xml")
+            ..
+            full_output.find("</project>").expect("failed to find end of xml") + 10
+        ).expect("failed to extract xml body");
+        sxd_document::parser::parse(xml).expect("failed to parse effective pom")
+    }
 }
 
 #[derive(Debug)]
@@ -77,6 +93,32 @@ impl From<cargo_metadata::Metadata> for ProjectInfo {
     }
 }
 
+impl ProjectInfo {
+    fn from_pom(pom: &sxd_document::Package) -> Self {
+        let document = pom.as_document();
+        
+        let mut context = sxd_xpath::context::Context::new();
+        context.set_namespace("mvn", "http://maven.apache.org/POM/4.0.0");
+        
+        let factory = sxd_xpath::Factory::new();
+        let name_xpath = factory.build("/mvn:project/mvn:name")
+            .expect("failed to compile name xpath")
+            .expect("No XPath was compiled");
+        let version_xpath = factory.build("/mvn:project/mvn:version")
+            .expect("failed to compile name xpath")
+            .expect("No XPath was compiled");
+        
+        ProjectInfo {
+            name: name_xpath.evaluate(&context, document.root())
+                .expect("failed to evaluate name expression")
+                .into_string(),
+            version: version_xpath.evaluate(&context, document.root())
+                .expect("failed to evaluate version expression")
+                .into_string(),
+        }        
+    }
+}
+
 pub struct Scouter {
     search_path: PathBuf
 }
@@ -129,4 +171,14 @@ mod test {
         assert_eq!(env!("CARGO_PKG_NAME"), project_info.name);
         assert_eq!(env!("CARGO_PKG_VERSION"), project_info.version);
     }
+    
+    #[test]
+    fn test_maven_project() {
+        let mut scouter = Scouter::new(format!("{}/testdata/maven", env!("CARGO_MANIFEST_DIR")));
+        let project = scouter.next().unwrap();
+        let project_info = project.info();
+        assert_eq!(ProjectType::Maven, project.project_type);
+        assert_eq!("Shenlong Maven Test Project", project_info.name);
+        assert_eq!("1.0.0-SNAPSHOT", project_info.version);
+    }
 }