Initial Commit.

src/env.rs

@@ -0,0 +1,44 @@
+use std::io;
+use std::path::Path;
+use std::str::FromStr;
+use std::sync::LazyLock;
+
+use crate::java::{JAVA_VM, VMFlag};
+
+use anyhow::Context;
+
+static JAVA_VERSION: LazyLock<String> = LazyLock::new(|| {
+    crate::io::run_process(&[JAVA_VM, VMFlag::Version.to_string().as_str()])
+        .expect("Failed to call java")
+        .0
+        .expect("Failed to read java version from stdout")
+});
+
+pub fn get_javac_ver() -> anyhow::Result<semver::Version> {
+    /*
+     * $ java --version
+     *      openjdk 21.0.9 2025-10-21
+     *      OpenJDK Runtime Environment (build 21.0.9+10)
+     *      OpenJDK 64-Bit Server VM (build 21.0.9+10, mixed mode, sharing)
+     */
+
+    semver::Version::from_str(
+        JAVA_VERSION
+            .lines()
+            .nth(0)
+            .context("stdout from Java is all f-cked up")?
+            .split_ascii_whitespace()
+            .nth(1)
+            .context("Java version position is all f-cked up")?,
+    )
+    .context("Failed to produce a version struct from string")
+}
+
+pub fn set_cwd<P: AsRef<Path>>(path: P) -> io::Result<()> {
+    let mut cwd = crate::PROJECT_ROOT
+        .lock()
+        .expect("Failed to lock Mutex")
+        .to_owned();
+    cwd.push(path.as_ref());
+    std::env::set_current_dir(cwd)
+}