This is an automated email from the ASF dual-hosted git repository.
agrove pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/datafusion-comet.git
The following commit(s) were added to refs/heads/main by this push:
new a1641ab4 Improve JNI safety (#600)
a1641ab4 is described below
commit a1641ab405dde33a85295010a237f53f433b673b
Author: Andy Grove <[email protected]>
AuthorDate: Thu Jun 27 11:48:36 2024 -0700
Improve JNI safety (#600)
---
core/src/jvm_bridge/mod.rs | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)
diff --git a/core/src/jvm_bridge/mod.rs b/core/src/jvm_bridge/mod.rs
index f91ae8fe..4a5f72f4 100644
--- a/core/src/jvm_bridge/mod.rs
+++ b/core/src/jvm_bridge/mod.rs
@@ -19,6 +19,7 @@
use crate::errors::CometResult;
+use jni::objects::JClass;
use jni::{
errors::Error,
objects::{JMethodID, JObject, JString, JThrowable, JValueGen, JValueOwned},
@@ -189,6 +190,12 @@ pub use comet_task_memory_manager::*;
/// The JVM classes that are used in the JNI calls.
pub struct JVMClasses<'a> {
+ /// Cached JClass for "java.lang.Object"
+ java_lang_object: JClass<'a>,
+ /// Cached JClass for "java.lang.Class"
+ java_lang_class: JClass<'a>,
+ /// Cached JClass for "java.lang.Throwable"
+ java_lang_throwable: JClass<'a>,
/// Cached method ID for "java.lang.Object#getClass"
pub object_get_class_method: JMethodID,
/// Cached method ID for "java.lang.Class#getName"
@@ -224,27 +231,32 @@ impl JVMClasses<'_> {
// `JNIEnv` except for creating the global references of the
classes.
let env = unsafe { std::mem::transmute::<&mut JNIEnv, &'static mut
JNIEnv>(env) };
- let clazz = env.find_class("java/lang/Object").unwrap();
+ let java_lang_object = env.find_class("java/lang/Object").unwrap();
let object_get_class_method = env
- .get_method_id(clazz, "getClass", "()Ljava/lang/Class;")
+ .get_method_id(&java_lang_object, "getClass",
"()Ljava/lang/Class;")
.unwrap();
- let clazz = env.find_class("java/lang/Class").unwrap();
+ let java_lang_class = env.find_class("java/lang/Class").unwrap();
let class_get_name_method = env
- .get_method_id(clazz, "getName", "()Ljava/lang/String;")
+ .get_method_id(&java_lang_class, "getName",
"()Ljava/lang/String;")
.unwrap();
- let clazz = env.find_class("java/lang/Throwable").unwrap();
+ let java_lang_throwable =
env.find_class("java/lang/Throwable").unwrap();
let throwable_get_message_method = env
- .get_method_id(clazz, "getMessage", "()Ljava/lang/String;")
+ .get_method_id(&java_lang_throwable, "getMessage",
"()Ljava/lang/String;")
.unwrap();
- let clazz = env.find_class("java/lang/Throwable").unwrap();
let throwable_get_cause_method = env
- .get_method_id(clazz, "getCause", "()Ljava/lang/Throwable;")
+ .get_method_id(&java_lang_throwable, "getCause",
"()Ljava/lang/Throwable;")
.unwrap();
+ // SAFETY: According to the documentation for `JMethodID`, it is
our
+ // responsibility to maintain a reference to the `JClass`
instances where the
+ // methods were accessed from to prevent the methods from being
garbage-collected
JVMClasses {
+ java_lang_object,
+ java_lang_class,
+ java_lang_throwable,
object_get_class_method,
class_get_name_method,
throwable_get_message_method,
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