1 use crate::{
2     objects::JObject,
3     sys::{jclass, jobject},
4 };
5 
6 /// Lifetime'd representation of a `jclass`. Just a `JObject` wrapped in a new
7 /// class.
8 #[repr(transparent)]
9 #[derive(Debug)]
10 pub struct JClass<'local>(JObject<'local>);
11 
12 impl<'local> AsRef<JClass<'local>> for JClass<'local> {
as_ref(&self) -> &JClass<'local>13     fn as_ref(&self) -> &JClass<'local> {
14         self
15     }
16 }
17 
18 impl<'local> AsRef<JObject<'local>> for JClass<'local> {
as_ref(&self) -> &JObject<'local>19     fn as_ref(&self) -> &JObject<'local> {
20         self
21     }
22 }
23 
24 impl<'local> ::std::ops::Deref for JClass<'local> {
25     type Target = JObject<'local>;
26 
deref(&self) -> &Self::Target27     fn deref(&self) -> &Self::Target {
28         &self.0
29     }
30 }
31 
32 impl<'local> From<JClass<'local>> for JObject<'local> {
from(other: JClass) -> JObject33     fn from(other: JClass) -> JObject {
34         other.0
35     }
36 }
37 
38 /// This conversion assumes that the `JObject` is a pointer to a class object.
39 impl<'local> From<JObject<'local>> for JClass<'local> {
from(other: JObject) -> Self40     fn from(other: JObject) -> Self {
41         unsafe { Self::from_raw(other.into_raw()) }
42     }
43 }
44 
45 /// This conversion assumes that the `JObject` is a pointer to a class object.
46 impl<'local, 'obj_ref> From<&'obj_ref JObject<'local>> for &'obj_ref JClass<'local> {
from(other: &'obj_ref JObject<'local>) -> Self47     fn from(other: &'obj_ref JObject<'local>) -> Self {
48         // Safety: `JClass` is `repr(transparent)` around `JObject`.
49         unsafe { &*(other as *const JObject<'local> as *const JClass<'local>) }
50     }
51 }
52 
53 impl<'local> std::default::Default for JClass<'local> {
default() -> Self54     fn default() -> Self {
55         Self(JObject::null())
56     }
57 }
58 
59 impl<'local> JClass<'local> {
60     /// Creates a [`JClass`] that wraps the given `raw` [`jclass`]
61     ///
62     /// # Safety
63     ///
64     /// `raw` may be a null pointer. If `raw` is not a null pointer, then:
65     ///
66     /// * `raw` must be a valid raw JNI local reference.
67     /// * There must not be any other `JObject` representing the same local reference.
68     /// * The lifetime `'local` must not outlive the local reference frame that the local reference
69     ///   was created in.
from_raw(raw: jclass) -> Self70     pub unsafe fn from_raw(raw: jclass) -> Self {
71         Self(JObject::from_raw(raw as jobject))
72     }
73 
74     /// Returns the raw JNI pointer.
as_raw(&self) -> jclass75     pub fn as_raw(&self) -> jclass {
76         self.0.as_raw() as jclass
77     }
78 
79     /// Unwrap to the raw jni type.
into_raw(self) -> jclass80     pub fn into_raw(self) -> jclass {
81         self.0.into_raw() as jclass
82     }
83 }
84