CefTask

Header: cef_task.h
Interfaces: CefTask, CefTaskRunner
Category: System Utilities

Overview

Tasks, threads, parsers, streams, cookies, URL requests, scheme registration, and constant tables.

CefTask (USER-IMPLEMENTED)

Source File: include/cef_task.h

Process / Thread Context: Defined by the target thread of the CefTaskRunner / CefPostTask call; the destructor may run on the source thread if posting failed, so destructors must be conservative.

Purpose: Implement this single-method interface to encapsulate a unit of asynchronous work that runs on a chosen CEF thread.

Methods

virtual void Execute() = 0

Parameters:

• (none)

Return Value: (none)

Usage Instruction: The body runs on the target thread. Perform work; do not block.

Threading Constraint: Target thread of the post.

Usage Example

class LogOnUiTask : public CefTask {
 public:
  explicit LogOnUiTask(std::string msg) : msg_(std::move(msg)) {}
  void Execute() override { LOG(INFO) << "on UI thread: " << msg_; }
 private:
  std::string msg_;
  IMPLEMENT_REFCOUNTING(LogOnUiTask);
};

// From any thread:
CefPostTask(TID_UI, new LogOnUiTask("hello"));

CefTaskRunner

Source File: include/cef_task.h

Process / Thread Context: Methods are safe to call on any thread. Tasks themselves execute on the runner's associated thread.

Purpose: Handle to a thread's message loop. Use GetForCurrentThread() or GetForThread(CefThreadId) to obtain a runner, then PostTask / PostDelayedTask to schedule work.

Methods

static CefRefPtr<CefTaskRunner> GetForCurrentThread()

Parameters:

• (none)

Return Value: Runner for the current thread, or empty ref if not a CEF thread.

Threading Constraint: Any thread.

static CefRefPtr<CefTaskRunner> GetForThread(CefThreadId threadId)

Parameters:

• threadId: any value from cef_thread_id_t.

Return Value: Runner for the specified CEF thread.

Threading Constraint: Any thread.

virtual bool IsSame(CefRefPtr<CefTaskRunner> that)

Return Value: true if same underlying runner. Any thread.

Threading Constraint: Threading constraint not specified in source.

virtual bool BelongsToCurrentThread()

Return Value: true if this runner is for the current thread. Any thread.

Threading Constraint: Threading constraint not specified in source.

virtual bool BelongsToThread(CefThreadId threadId)

Return Value: true if this runner belongs to threadId. Any thread.

Threading Constraint: Threading constraint not specified in source.

virtual bool PostTask(CefRefPtr<CefTask> task)

Parameters:

• task: task to run asynchronously.

Return Value: true if successfully posted.

Threading Constraint: Any thread.

virtual bool PostDelayedTask(CefRefPtr<CefTask> task, int64_t delay_ms)

Parameters:

• task: task to run; delay_ms: millisecond delay.

Return Value: true on success. Note: Delayed tasks are not supported on V8 WebWorker threads — they execute without delay.

Threading Constraint: Any thread.

Usage Example

// Schedule UI work with a delay from any thread.
auto runner = CefTaskRunner::GetForThread(TID_UI);
runner->PostDelayedTask(new LogOnUiTask("delayed"), 2000);

// Or use the convenience free functions (next section):
CefPostDelayedTask(TID_UI, new LogOnUiTask("delayed"), 2000);