Struct java_spaghetti::VM

pub struct VM(/* private fields */);

FFI: Use &VM instead of *const JavaVM. This represents a global, process-wide Java exection environment.

On Android, there is only one VM per-process, although on desktop it’s possible (if rare) to have multiple VMs within the same process. This library does not support having multiple VMs active simultaniously.

This is a “safe” alternative to jni_sys::JavaVM raw pointers, with the following caveats:

1. A null vm will result in undefined behavior. Java should not be invoking your native functions with a null *mut JavaVM, however, so I don’t believe this is a problem in practice unless you’ve bindgened the C header definitions elsewhere, calling them (requiring unsafe), and passing null pointers (generally UB for JNI functions anyways, so can be seen as a caller soundness issue.)

2. Allowing the underlying JavaVM to be modified is undefined behavior. I don’t believe the JNI libraries modify the JavaVM, so as long as you’re not accepting a *mut JavaVM elsewhere, using unsafe to dereference it, and mucking with the methods on it yourself, I believe this “should” be fine.

Implementations

impl VM

pub fn as_raw(&self) -> *mut JavaVM

pub unsafe fn from_raw(vm: *mut JavaVM) -> Self

pub fn with_env<F, R>(&self, callback: F) -> R

where F: for<'env> FnOnce(Env<'env>) -> R,

Trait Implementations

impl Clone for VM

fn clone(&self) -> VM

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VM

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for VM

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for VM

fn cmp(&self, other: &VM) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for VM

fn eq(&self, other: &VM) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for VM

fn partial_cmp(&self, other: &VM) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for VM

impl Eq for VM

impl Send for VM

impl StructuralPartialEq for VM

impl Sync for VM