firebase::FutureBase

#include <future.h>

Type-independent return type of asynchronous calls.

Summary

See also:Future for code samples.

Inheritance

Direct Known Subclasses:firebase::Future< ResultType >

Constructors and Destructors
`FutureBase()` Construct an untyped future.
`FutureBase(const FutureBase & rhs)` Copy constructor and operator.
`~FutureBase()`

Public types
`CompletionCallback)(const FutureBase &result_data, void *user_data)`	typedef `void(*` Function pointer for a completion callback.

Public functions
`Error() const`	`int` When Status() is kFutureStatusComplete, returns the API-defined error code.
`ErrorMessage() const`	`const char *` When Status() is kFutureStatusComplete, returns the API-defined error message, as human-readable text, or an empty string if the API does not provide a human readable description of the error.
`OnCompletion(CompletionCallback callback, void *user_data) const`	`void` Register a callback that will be called at most once, when the future is completed.
`Release()`	`void` Explicitly release the internal resources for a future.
`ResultVoid() const`	`const void *` Result of the asynchronous call, or nullptr if the result is still pending.
`Status() const`	`FutureStatus` Completion status of the asynchronous call.
`operator=(const FutureBase & rhs)`	`FutureBase &` Copy an untyped future.

Public types

CompletionCallback

void(* CompletionCallback)(const FutureBase &result_data, void *user_data)

Function pointer for a completion callback.

When we call this, we will send the completed future, along with the user data that you specified when you set up the callback.

Public functions

Error

int Error() const

When Status() is kFutureStatusComplete, returns the API-defined error code.

Otherwise, return value is undefined.

ErrorMessage

const char * ErrorMessage() const

When Status() is kFutureStatusComplete, returns the API-defined error message, as human-readable text, or an empty string if the API does not provide a human readable description of the error.

Note:The returned pointer is only valid for the lifetime of the Future or its copies.

FutureBase

 FutureBase()

Construct an untyped future.

FutureBase

 FutureBase(
  const FutureBase & rhs
)

Copy constructor and operator.

Increment the reference count when creating a copy of the future.

OnCompletion

void OnCompletion(
  CompletionCallback callback,
  void *user_data
) const

If you call OnCompletion() itself more than once, only the most recent callback you registered be called.

When your callback is called, the user_data that you supplied here will be passed back as the second parameter.

Details

Parameters

`callback`	Function pointer to your callback.
`user_data`	Optional user data. We will pass this back to your callback.

Release

void Release()

Explicitly release the internal resources for a future.

Future will become invalid.

ResultVoid

const void * ResultVoid() const

Result of the asynchronous call, or nullptr if the result is still pending.

Cast is required since GetFutureResult() returns void*.

Status

FutureStatus Status() const

Completion status of the asynchronous call.

operator=

FutureBase & operator=(
  const FutureBase & rhs
)

Copy an untyped future.

~FutureBase

 ~FutureBase()

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Last updated November 19, 2016.

firebase::FutureBase

Summary

Inheritance

Constructors and Destructors

Public types

Public functions

Public types

CompletionCallback

Public functions

Error

ErrorMessage

FutureBase

FutureBase

OnCompletion

Release

ResultVoid

Status

operator=

~FutureBase

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