1 files changed, 71 insertions, 0 deletions
diff --git a/src/wrapper/strings/java_str.rs b/src/wrapper/strings/java_str.rs
new file mode 100644
index 0000000..2829ce6
--- /dev/null
+++ b/src/wrapper/strings/java_str.rs
@@ -0,0 +1,71 @@
+use std::{borrow::Cow, os::raw::c_char};
+
+use log::warn;
+
+use crate::{errors::*, objects::JString, strings::JNIStr, JNIEnv};
+
+/// Reference to a string in the JVM. Holds a pointer to the array
+/// returned by GetStringUTFChars. Calls ReleaseStringUTFChars on Drop.
+/// Can be converted to a `&JNIStr` with the same cost as the `&CStr.from_ptr`
+/// conversion.
+pub struct JavaStr<'a: 'b, 'b> {
+    internal: *const c_char,
+    obj: JString<'a>,
+    env: &'b JNIEnv<'a>,
+}
+
+impl<'a: 'b, 'b> JavaStr<'a, 'b> {
+    /// Build a `JavaStr` from an object and a reference to the environment. You
+    /// probably want to use `JNIEnv::get_string` instead.
+    pub fn from_env(env: &'b JNIEnv<'a>, obj: JString<'a>) -> Result<Self> {
+        let ptr = env.get_string_utf_chars(obj)?;
+        let java_str = JavaStr {
+            internal: ptr,
+            env,
+            obj,
+        };
+        Ok(java_str)
+    }
+
+    /// Extract the raw C string pointer from the JavaStr. This will be
+    /// encoded using the JVM internal `CESU-8`-style.
+    pub fn get_raw(&self) -> *const c_char {
+        self.internal
+    }
+}
+
+impl<'a: 'b, 'b> ::std::ops::Deref for JavaStr<'a, 'b> {
+    type Target = JNIStr;
+    fn deref(&self) -> &Self::Target {
+        self.into()
+    }
+}
+
+impl<'a: 'b, 'b: 'c, 'c> From<&'c JavaStr<'a, 'b>> for &'c JNIStr {
+    fn from(other: &'c JavaStr) -> &'c JNIStr {
+        unsafe { JNIStr::from_ptr(other.internal) }
+    }
+}
+
+impl<'a: 'b, 'b: 'c, 'c> From<&'c JavaStr<'a, 'b>> for Cow<'c, str> {
+    fn from(other: &'c JavaStr) -> Cow<'c, str> {
+        let jni_str: &JNIStr = &*other;
+        jni_str.into()
+    }
+}
+
+impl<'a: 'b, 'b> From<JavaStr<'a, 'b>> for String {
+    fn from(other: JavaStr) -> String {
+        let cow: Cow<str> = (&other).into();
+        cow.into_owned()
+    }
+}
+
+impl<'a: 'b, 'b> Drop for JavaStr<'a, 'b> {
+    fn drop(&mut self) {
+        match self.env.release_string_utf_chars(self.obj, self.internal) {
+            Ok(()) => {}
+            Err(e) => warn!("error dropping java str: {}", e),
+        }
+    }
+}