Refactor: Modify command registraion on bootup

Benefits of this CL:

* Commands no longer rely on closured proc struct
* No two-step process for basic command initializaion

command/command.go

@@ -3,11 +3,17 @@
 package command
 
 import (
+	"debug/gosym"
 	"fmt"
 	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"github.com/derekparker/dbg/proctl"
 )
 
-type cmdfunc func(args ...string) error
+type cmdfunc func(proc *proctl.DebuggedProcess, args ...string) error
 
 type Commands struct {
 	cmds map[string]cmdfunc
@@ -16,8 +22,12 @@ type Commands struct {
 // Returns a Commands struct with default commands defined.
 func DebugCommands() *Commands {
 	cmds := map[string]cmdfunc{
-		"exit": exitFunc,
-		"":     nullCommand,
+		"exit":     exitFunc,
+		"continue": cont,
+		"break":    br,
+		"step":     step,
+		"clear":    clear,
+		"":         nullCommand,
 	}
 
 	return &Commands{cmds}
@@ -45,20 +55,101 @@ func (c *Commands) Find(cmdstr string) cmdfunc {
 }
 
 func CommandFunc(fn func() error) cmdfunc {
-	return func(args ...string) error {
+	return func(p *proctl.DebuggedProcess, args ...string) error {
 		return fn()
 	}
 }
 
-func noCmdAvailable(args ...string) error {
+func noCmdAvailable(p *proctl.DebuggedProcess, ars ...string) error {
 	return fmt.Errorf("command not available")
 }
 
-func exitFunc(args ...string) error {
+func exitFunc(p *proctl.DebuggedProcess, ars ...string) error {
 	os.Exit(0)
 	return nil
 }
 
-func nullCommand(args ...string) error {
+func nullCommand(p *proctl.DebuggedProcess, ars ...string) error {
+	return nil
+}
+
+func cont(p *proctl.DebuggedProcess, ars ...string) error {
+	return p.Continue()
+}
+
+func step(p *proctl.DebuggedProcess, args ...string) error {
+	err := p.Step()
+	if err != nil {
+		return err
+	}
+
+	regs, err := p.Registers()
+	if err != nil {
+		return err
+	}
+
+	f, l, _ := p.GoSymTable.PCToLine(regs.PC())
+	fmt.Printf("Stopped at: %s:%d\n", f, l)
+
+	return nil
+}
+
+func clear(p *proctl.DebuggedProcess, args ...string) error {
+	fname := args[0]
+	fn := p.GoSymTable.LookupFunc(fname)
+	if fn == nil {
+		return fmt.Errorf("No function named %s", fname)
+	}
+
+	bp, err := p.Clear(fn.Entry)
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("Breakpoint cleared at %#v for %s %s:%d\n", bp.Addr, bp.FunctionName, bp.File, bp.Line)
+
+	return nil
+}
+
+func br(p *proctl.DebuggedProcess, args ...string) error {
+	var (
+		fn    *gosym.Func
+		pc    uint64
+		fname = args[0]
+	)
+
+	if strings.ContainsRune(fname, ':') {
+		fl := strings.Split(fname, ":")
+
+		f, err := filepath.Abs(fl[0])
+		if err != nil {
+			return err
+		}
+
+		l, err := strconv.Atoi(fl[1])
+		if err != nil {
+			return err
+		}
+
+		pc, fn, err = p.GoSymTable.LineToPC(f, l)
+		if err != nil {
+			return err
+		}
+	} else {
+		fn = p.GoSymTable.LookupFunc(fname)
+		pc = fn.Entry
+	}
+
+	if fn == nil {
+		return fmt.Errorf("No function named %s", fname)
+	}
+
+	bp, err := p.Break(uintptr(pc))
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("Breakpoint set at %#v for %s %s:%d\n", bp.Addr, bp.FunctionName, bp.File, bp.Line)
+
 	return nil
 }