Golang Program.Resume方法代码示例

// programLoop runs the program being debugged to completion.  When a breakpoint's
// conditions are satisfied, it sends an Update RPC to the Debuglet Controller.
// The function returns when the program exits and all Update RPCs have finished.
func programLoop(c *debuglet.Controller, bs *breakpoints.BreakpointStore, prog debug.Program) {
	var wg sync.WaitGroup
	for {
		// Run the program until it hits a breakpoint or exits.
		status, err := prog.Resume()
		if err != nil {
			break
		}

		// Get the breakpoints at this address whose conditions were satisfied,
		// and remove the ones that aren't logpoints.
		bps := bs.BreakpointsAtPC(status.PC)
		bps = bpsWithConditionSatisfied(bps, prog)
		for _, bp := range bps {
			if bp.Action != "LOG" {
				bs.RemoveBreakpoint(bp)
			}
		}

		if len(bps) == 0 {
			continue
		}

		// Evaluate expressions and get the stack.
		vc := valuecollector.NewCollector(prog, maxCapturedVariables)
		needStackFrames := false
		for _, bp := range bps {
			// If evaluating bp's condition didn't return an error, evaluate bp's
			// expressions, and later get the stack frames.
			if bp.Status == nil {
				bp.EvaluatedExpressions = expressionValues(bp.Expressions, prog, vc)
				needStackFrames = true
			}
		}
		var (
			stack                    []*cd.StackFrame
			stackFramesStatusMessage *cd.StatusMessage
		)
		if needStackFrames {
			stack, stackFramesStatusMessage = stackFrames(prog, vc)
		}

		// Read variable values from the program.
		variableTable := vc.ReadValues()

		// Start a goroutine to send updates to the Debuglet Controller or write
		// to logs, concurrently with resuming the program.
		// TODO: retry Update on failure.
		for _, bp := range bps {
			wg.Add(1)
			switch bp.Action {
			case "LOG":
				go func(format string, evaluatedExpressions []*cd.Variable) {
					s := valuecollector.LogString(format, evaluatedExpressions, variableTable)
					log.Print(s)
					wg.Done()
				}(bp.LogMessageFormat, bp.EvaluatedExpressions)
				bp.Status = nil
				bp.EvaluatedExpressions = nil
			default:
				go func(bp *cd.Breakpoint) {
					defer wg.Done()
					bp.IsFinalState = true
					if bp.Status == nil {
						// If evaluating bp's condition didn't return an error, include the
						// stack frames, variable table, and any status message produced when
						// getting the stack frames.
						bp.StackFrames = stack
						bp.VariableTable = variableTable
						bp.Status = stackFramesStatusMessage
					}
					if err := c.Update(bp.Id, bp); err != nil {
						log.Printf("Failed to send breakpoint update for %s: %s", bp.Id, err)
					}
				}(bp)
			}
		}
	}

	// Wait for all updates to finish before returning.
	wg.Wait()
}