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Dispatch

rs_teststand_sys

Trait Dispatch 

Source 
pub trait Dispatch: Debug {
    // Required methods
    fn get(&self, dispid: i32) -> Result<Value, ComError>;
    fn put(&self, dispid: i32, value: Value) -> Result<(), ComError>;
    fn call(&self, dispid: i32, args: &[Value]) -> Result<Value, ComError>;

    // Provided methods
    fn call_with_outputs(
        &self,
        dispid: i32,
        args: &[Value],
        outputs: &[OutKind],
    ) -> Result<(Value, Vec<Value>), ComError> { ... }
    fn duplicate(&self) -> Option<Box<dyn Dispatch>> { ... }
    fn as_idispatch(&self) -> Option<&IDispatch> { ... }
}
Expand description

The late-bound call surface a wrapper needs from a COM object.

Kept deliberately small; it grows a member only when a wrapper first needs one, each with its own test.

Required Methods§

Source

fn get(&self, dispid: i32) -> Result<Value, ComError>

Reads a property by dispatch id (DISPATCH_PROPERTYGET, no arguments).

§Errors

ComError::Hresult if the COM call fails, or ComError::UnexpectedType if the returned value has an unmodeled type.

Source

fn put(&self, dispid: i32, value: Value) -> Result<(), ComError>

Sets a property by dispatch id (DISPATCH_PROPERTYPUT).

Required, deliberately: a default body returning “not implemented” would be a stub that silently turns a missing implementation into a runtime error. Making it required turns that into a compile error instead.

§Errors

ComError::Hresult if the COM call fails.

Source

fn call(&self, dispid: i32, args: &[Value]) -> Result<Value, ComError>

Invokes a method by dispatch id (DISPATCH_METHOD) with arguments.

Required for the same reason as Dispatch::put.

§Errors

ComError::Hresult if the COM call fails, or ComError::UnexpectedType if the returned value has an unmodeled type.

Provided Methods§

Source

fn call_with_outputs( &self, dispid: i32, args: &[Value], outputs: &[OutKind], ) -> Result<(Value, Vec<Value>), ComError>

Calls a member that reports part of its answer through by-reference arguments.

The outputs describe slots appended after args, in declaration order. Returns the member’s own result together with what it wrote into each slot.

§Errors

ComError if the call fails, or ComError::UnexpectedType on a dispatch that has no COM identity to call through.

Source

fn duplicate(&self) -> Option<Box<dyn Dispatch>>

An owned handle to the same COM object, when there is one.

COM interface pointers are reference counted, so duplicating one is a refcount bump rather than a copy of the object. This exists because passing an object back to the engine needs an owned handle, and a caller normally only has a borrow.

Returns None for test fakes, which have no COM identity to share.

Source

fn as_idispatch(&self) -> Option<&IDispatch>

The underlying IDispatch, when this really is a live COM object.

Returns None for test fakes, which is what stops a fake from being marshalled into a VARIANT and handed to the engine.

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§