[rfc][icedtea-web] spawning linux jvm in rust lunchers

[Jiri Vanek]

Thank y ou for review!

> 
> Please use the following instead of get_sliced_first_arg:
> 
> let args = env::args().skip(1).collect()

Coool! Missed this in docs. Done
> 
> 
>>      * rust-launcher/src/os_access.rs: (Os) declared new method ofspawn_java_process. (Linux) 
>> implementing it by spawn
> 
> 1. Don't see a reason to use copy/move for its arguments, I'd rather use:
> 
> jre_dir: &std::path::PathBuf, args: &Vec<String>

Uf, That would mean, that javadir going in,  will change to path to java bin. That is unexpected. So 
I kept original
> 
> 
> 2. clone is not needed in args.clone().into_iter()

After changing  signature to &Vec<String>, done

> 
> 3. please setup std in/out/err handling explicitly (even if you want to inherit all of them)

Well, done, but why?
> 
> 4. in error message a space is needed between "," and "\"

nice catch
> 
> 
>>      * rust-launcher/src/utils.rs: added and tested new methods to slice out first member of 
>> vector and to cut first param  of  input arguments
> 
> get_sliced_first_arg is not needed.
> 

Right :)

TYVM!




diff -r 88f126034b7b rust-launcher/src/jvm_from_properties_resolver.rs
--- a/rust-launcher/src/jvm_from_properties_resolver.rs	Tue Oct 02 18:32:02 2018 +0200
+++ b/rust-launcher/src/jvm_from_properties_resolver.rs	Thu Oct 04 18:02:43 2018 +0200
@@ -94,6 +94,10 @@
          fn get_registry_jdk(&self) -> Option<std::path::PathBuf> {
              None
          }
+
+        fn spawn_java_process(&self, jre_dir: std::path::PathBuf, args: &Vec<String>) -> u32 {
+            return 0;
+        }
      }

      #[test]
diff -r 88f126034b7b rust-launcher/src/main.rs
--- a/rust-launcher/src/main.rs	Tue Oct 02 18:32:02 2018 +0200
+++ b/rust-launcher/src/main.rs	Thu Oct 04 18:02:43 2018 +0200
@@ -65,4 +65,7 @@
      write!(&mut info2, "{}", "selected jre: ").expect("unwrap failed");
      write!(&mut info2, "{}", java_dir.display()).expect("unwrap failed");
      os.info(&info2);
+    os.spawn_java_process(java_dir, &(env::args().skip(1).collect()));
  }
+
+
diff -r 88f126034b7b rust-launcher/src/os_access.rs
--- a/rust-launcher/src/os_access.rs	Tue Oct 02 18:32:02 2018 +0200
+++ b/rust-launcher/src/os_access.rs	Thu Oct 04 18:02:43 2018 +0200
@@ -5,6 +5,7 @@
      fn log(&self, s: &str);
      fn info(&self, s: &str);
      fn get_registry_jdk(&self) -> Option<std::path::PathBuf>;
+    fn spawn_java_process(&self, jre_dir: std::path::PathBuf, args: &Vec<String>) -> u32;
  }

  pub struct Linux {
@@ -31,4 +32,23 @@
      fn get_registry_jdk(&self) -> Option<std::path::PathBuf> {
          None
      }
+
+    fn spawn_java_process(&self, jre_dir: std::path::PathBuf, args: &Vec<String>) -> u32 {
+        let mut bin_java = jre_dir.clone();
+        bin_java.push("bin");
+        bin_java.push("java");
+        let mut cmd = std::process::Command::new(&bin_java);
+        for ar in args.into_iter() {
+            cmd.arg(ar);
+        }
+        cmd.stdin(std::process::Stdio::inherit());
+        cmd.stdout(std::process::Stdio::inherit());
+        cmd.stderr(std::process::Stdio::inherit());
+        let res = cmd.spawn();
+        match res {
+            Ok(child) => child.id(),
+            Err(_) => panic!("Error spawning JVM process,\
+                 java executable: [{}], arguments: [{:?}]", 
bin_java.into_os_string().to_str().expect("path should unwrap"), args)
+        }
+    }
  }