dlv: Misc refactors

cmd/dlv/cmds/commands.go

@@ -255,7 +255,7 @@ func traceCmd(cmd *cobra.Command, args []string) {
 			return 1
 		}
 		for i := range funcs {
-			_, err := client.CreateBreakpoint(&api.Breakpoint{FunctionName: funcs[i], Tracepoint: true, Line: -1, Stacktrace: traceStackDepth})
+			_, err = client.CreateBreakpoint(&api.Breakpoint{FunctionName: funcs[i], Tracepoint: true, Line: -1, Stacktrace: traceStackDepth})
 			if err != nil {
 				fmt.Fprintln(os.Stderr, err)
 				return 1

config/config.go

@@ -24,7 +24,7 @@ type Config struct {
 func LoadConfig() *Config {
 	err := createConfigPath()
 	if err != nil {
-		fmt.Printf("Could not create config directory: %v.")
+		fmt.Printf("Could not create config directory: %v.", err)
 		return nil
 	}
 	fullConfigFile, err := GetConfigFilePath(configFile)

proc/breakpoints.go

@@ -25,8 +25,8 @@ type Breakpoint struct {
 
 	// Breakpoint information
 	Tracepoint    bool           // Tracepoint flag
-	Stacktrace    int            // Number of stack frames to retrieve
 	Goroutine     bool           // Retrieve goroutine information
+	Stacktrace    int            // Number of stack frames to retrieve
 	Variables     []string       // Variables to evaluate
 	HitCount      map[int]uint64 // Number of times a breakpoint has been reached in a certain goroutine
 	TotalHitCount uint64         // Number of times a breakpoint has been reached

proc/eval.go

@@ -9,10 +9,10 @@ import (
 	"go/parser"
 	"go/printer"
 	"go/token"
-	"golang.org/x/debug/dwarf"
 	"reflect"
 
 	"github.com/derekparker/delve/dwarf/reader"
+	"golang.org/x/debug/dwarf"
 )
 
 // EvalExpression returns the value of the given expression.
@@ -430,25 +430,26 @@ func (scope *EvalScope) evalIdent(node *ast.Ident) (*Variable, error) {
 
 	// try to interpret this as a local variable
 	v, err := scope.extractVarInfo(node.Name)
-	if err != nil {
+	if err == nil {
-		origErr := err
+		return v, nil
-		// workaround: sometimes go inserts an entry for '&varname' instead of varname
+	}
-		v, err = scope.extractVarInfo("&" + node.Name)
+	origErr := err
-		if err != nil {
+	// workaround: sometimes go inserts an entry for '&varname' instead of varname
-			// if it's not a local variable then it could be a package variable w/o explicit package name
+	v, err = scope.extractVarInfo("&" + node.Name)
-			_, _, fn := scope.Thread.dbp.PCToLine(scope.PC)
+	if err == nil {
-			if fn != nil {
-				if v, err := scope.packageVarAddr(fn.PackageName() + "." + node.Name); err == nil {
-					v.Name = node.Name
-					return v, nil
-				}
-			}
-			return nil, origErr
-		}
 		v = v.maybeDereference()
 		v.Name = node.Name
+		return v, nil
 	}
-	return v, nil
+	// if it's not a local variable then it could be a package variable w/o explicit package name
+	_, _, fn := scope.Thread.dbp.PCToLine(scope.PC)
+	if fn != nil {
+		if v, err = scope.packageVarAddr(fn.PackageName() + "." + node.Name); err == nil {
+			v.Name = node.Name
+			return v, nil
+		}
+	}
+	return nil, origErr
 }
 
 // Evaluates expressions <subexpr>.<field name> where subexpr is not a package name

proc/proc.go

@@ -49,11 +49,11 @@ type Process struct {
 	goSymTable              *gosym.Table
 	frameEntries            frame.FrameDescriptionEntries
 	lineInfo                line.DebugLines
-	firstStart              bool
 	os                      *OSProcessDetails
 	arch                    Arch
 	breakpointIDCounter     int
 	tempBreakpointIDCounter int
+	firstStart              bool
 	halt                    bool
 	exited                  bool
 	ptraceChan              chan func()

proc/stack.go

@@ -84,9 +84,9 @@ func (n NullAddrError) Error() string {
 type StackIterator struct {
 	pc, sp uint64
 	top    bool
+	atend  bool
 	frame  Stackframe
 	dbp    *Process
-	atend  bool
 	err    error
 }
 

proc/threads.go

@@ -396,16 +396,16 @@ func (thread *Thread) onRuntimeBreakpoint() bool {
 	return loc.Fn != nil && loc.Fn.Name == "runtime.breakpoint"
 }
 
-// Returns true if this thread is on the goroutine requested by the current 'next' command
+// onNextGorutine returns true if this thread is on the goroutine requested by the current 'next' command
-func (th *Thread) onNextGoroutine() (bool, error) {
+func (thread *Thread) onNextGoroutine() (bool, error) {
 	var bp *Breakpoint
-	for i := range th.dbp.Breakpoints {
+	for i := range thread.dbp.Breakpoints {
-		if th.dbp.Breakpoints[i].Temp {
+		if thread.dbp.Breakpoints[i].Temp {
-			bp = th.dbp.Breakpoints[i]
+			bp = thread.dbp.Breakpoints[i]
 		}
 	}
 	if bp == nil {
 		return false, nil
 	}
-	return bp.checkCondition(th)
+	return bp.checkCondition(thread)
 }

proc/variables.go

@@ -8,11 +8,12 @@ import (
 	"go/constant"
 	"go/parser"
 	"go/token"
-	"golang.org/x/debug/dwarf"
 	"reflect"
 	"strings"
 	"unsafe"
 
+	"golang.org/x/debug/dwarf"
+
 	"github.com/derekparker/delve/dwarf/op"
 	"github.com/derekparker/delve/dwarf/reader"
 )

service/api/prettyprint.go

@@ -3,6 +3,7 @@ package api
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"reflect"
 )
 
@@ -13,14 +14,14 @@ const (
 	indentString = "\t"
 )
 
-// Returns a representation of v on a single line
+// SinglelineString returns a representation of v on a single line.
 func (v *Variable) SinglelineString() string {
 	var buf bytes.Buffer
 	v.writeTo(&buf, true, false, true, "")
 	return buf.String()
 }
 
-// Returns a representation of v on multiple lines
+// MultilineString returns a representation of v on multiple lines.
 func (v *Variable) MultilineString(indent string) string {
 	var buf bytes.Buffer
 	buf.WriteString(indent)
@@ -28,7 +29,7 @@ func (v *Variable) MultilineString(indent string) string {
 	return buf.String()
 }
 
-func (v *Variable) writeTo(buf *bytes.Buffer, top, newlines, includeType bool, indent string) {
+func (v *Variable) writeTo(buf io.Writer, top, newlines, includeType bool, indent string) {
 	if v.Unreadable != "" {
 		fmt.Fprintf(buf, "(unreadable %s)", v.Unreadable)
 		return
@@ -101,7 +102,7 @@ func (v *Variable) writeTo(buf *bytes.Buffer, top, newlines, includeType bool, i
 	}
 }
 
-func (v *Variable) writeStringTo(buf *bytes.Buffer) {
+func (v *Variable) writeStringTo(buf io.Writer) {
 	s := v.Value
 	if len(s) != int(v.Len) {
 		s = fmt.Sprintf("%s...+%d more", s, int(v.Len)-len(s))
@@ -109,21 +110,21 @@ func (v *Variable) writeStringTo(buf *bytes.Buffer) {
 	fmt.Fprintf(buf, "%q", s)
 }
 
-func (v *Variable) writeSliceTo(buf *bytes.Buffer, newlines, includeType bool, indent string) {
+func (v *Variable) writeSliceTo(buf io.Writer, newlines, includeType bool, indent string) {
 	if includeType {
 		fmt.Fprintf(buf, "%s len: %d, cap: %d, ", v.Type, v.Len, v.Cap)
 	}
 	v.writeSliceOrArrayTo(buf, newlines, indent)
 }
 
-func (v *Variable) writeArrayTo(buf *bytes.Buffer, newlines, includeType bool, indent string) {
+func (v *Variable) writeArrayTo(buf io.Writer, newlines, includeType bool, indent string) {
 	if includeType {
 		fmt.Fprintf(buf, "%s ", v.Type)
 	}
 	v.writeSliceOrArrayTo(buf, newlines, indent)
 }
 
-func (v *Variable) writeStructTo(buf *bytes.Buffer, newlines, includeType bool, indent string) {
+func (v *Variable) writeStructTo(buf io.Writer, newlines, includeType bool, indent string) {
 	if int(v.Len) != len(v.Children) {
 		fmt.Fprintf(buf, "(*%s)(0x%x)", v.Type, v.Addr)
 		return
@@ -157,7 +158,7 @@ func (v *Variable) writeStructTo(buf *bytes.Buffer, newlines, includeType bool,
 	fmt.Fprintf(buf, "}")
 }
 
-func (v *Variable) writeMapTo(buf *bytes.Buffer, newlines, includeType bool, indent string) {
+func (v *Variable) writeMapTo(buf io.Writer, newlines, includeType bool, indent string) {
 	if includeType {
 		fmt.Fprintf(buf, "%s ", v.Type)
 	}
@@ -261,7 +262,7 @@ func (v *Variable) shouldNewlineStruct(newlines bool) bool {
 	return false
 }
 
-func (v *Variable) writeSliceOrArrayTo(buf *bytes.Buffer, newlines bool, indent string) {
+func (v *Variable) writeSliceOrArrayTo(buf io.Writer, newlines bool, indent string) {
 	nl := v.shouldNewlineArray(newlines)
 	fmt.Fprintf(buf, "[")
 

service/api/types.go

@@ -3,10 +3,11 @@ package api
 import (
 	"errors"
 	"fmt"
-	"github.com/derekparker/delve/proc"
 	"reflect"
 	"strconv"
 	"unicode"
+
+	"github.com/derekparker/delve/proc"
 )
 
 // DebuggerState represents the current context of the debugger.
@@ -46,10 +47,10 @@ type Breakpoint struct {
 
 	// tracepoint flag
 	Tracepoint bool `json:"continue"`
-	// number of stack frames to retrieve
-	Stacktrace int `json:"stacktrace"`
 	// retrieve goroutine information
 	Goroutine bool `json:"goroutine"`
+	// number of stack frames to retrieve
+	Stacktrace int `json:"stacktrace"`
 	// variables to evaluate
 	Variables []string `json:"variables,omitempty"`
 	// number of times a breakpoint has been reached in a certain goroutine

terminal/command.go

@@ -311,24 +311,23 @@ func (c *Commands) goroutine(t *Term, ctx callContext, argstr string) error {
 		}
 		if args[0] == "" {
 			return printscope(t)
-		} else {
-			gid, err := strconv.Atoi(argstr)
-			if err != nil {
-				return err
-			}
-
-			oldState, err := t.client.GetState()
-			if err != nil {
-				return err
-			}
-			newState, err := t.client.SwitchGoroutine(gid)
-			if err != nil {
-				return err
-			}
-
-			fmt.Printf("Switched from %d to %d (thread %d)\n", oldState.SelectedGoroutine.ID, gid, newState.CurrentThread.ID)
-			return nil
 		}
+		gid, err := strconv.Atoi(argstr)
+		if err != nil {
+			return err
+		}
+
+		oldState, err := t.client.GetState()
+		if err != nil {
+			return err
+		}
+		newState, err := t.client.SwitchGoroutine(gid)
+		if err != nil {
+			return err
+		}
+
+		fmt.Printf("Switched from %d to %d (thread %d)\n", oldState.SelectedGoroutine.ID, gid, newState.CurrentThread.ID)
+		return nil
 	case 2:
 		args = append(args, "")
 	}
@@ -345,8 +344,6 @@ func (c *Commands) goroutine(t *Term, ctx callContext, argstr string) error {
 func (c *Commands) frame(t *Term, ctx callContext, args string) error {
 	v := strings.SplitN(args, " ", 3)
 
-	var err error
-
 	switch len(v) {
 	case 0, 1:
 		return errors.New("not enough arguments")
@@ -354,6 +351,7 @@ func (c *Commands) frame(t *Term, ctx callContext, args string) error {
 		v = append(v, "")
 	}
 
+	var err error
 	ctx.Prefix = scopePrefix
 	ctx.Scope.Frame, err = strconv.Atoi(v[0])
 	if err != nil {
@@ -592,7 +590,7 @@ func setBreakpoint(t *Term, tracepoint bool, argstr string) error {
 		requestedBp.Name = ""
 		locspec = argstr
 		var err2 error
-		locs, err2 = t.client.FindLocation(api.EvalScope{-1, 0}, locspec)
+		locs, err2 = t.client.FindLocation(api.EvalScope{GoroutineID: -1, Frame: 0}, locspec)
 		if err2 != nil {
 			return err
 		}
@@ -1051,13 +1049,11 @@ func exitCommand(t *Term, ctx callContext, args string) error {
 	return ExitRequestError{}
 }
 
-func getBreakpointByIDOrName(t *Term, arg string) (bp *api.Breakpoint, err error) {
+func getBreakpointByIDOrName(t *Term, arg string) (*api.Breakpoint, error) {
 	if id, err := strconv.Atoi(arg); err == nil {
-		bp, err = t.client.GetBreakpoint(id)
+		return t.client.GetBreakpoint(id)
-	} else {
-		bp, err = t.client.GetBreakpointByName(arg)
 	}
-	return
+	return t.client.GetBreakpointByName(arg)
 }
 
 func (c *Commands) onCmd(t *Term, ctx callContext, argstr string) error {
@@ -1154,7 +1150,6 @@ func formatBreakpointLocation(bp *api.Breakpoint) string {
 	p := ShortenFilePath(bp.File)
 	if bp.FunctionName != "" {
 		return fmt.Sprintf("%#v for %s() %s:%d", bp.Addr, bp.FunctionName, p, bp.Line)
-	} else {
-		return fmt.Sprintf("%#v for %s:%d", bp.Addr, p, bp.Line)
 	}
+	return fmt.Sprintf("%#v for %s:%d", bp.Addr, p, bp.Line)
 }

terminal/terminal.go

@@ -102,7 +102,6 @@ func (t *Term) Run() (int, error) {
 		}
 	}
 
-	var status int
 	for {
 		cmdstr, err := t.promptForInput()
 		if err != nil {
@@ -110,8 +109,7 @@ func (t *Term) Run() (int, error) {
 				fmt.Println("exit")
 				return t.handleExit()
 			}
-			err, status = fmt.Errorf("Prompt for input failed.\n"), 1
+			return 1, fmt.Errorf("Prompt for input failed.\n")
-			break
 		}
 
 		cmdstr, args := parseCommand(cmdstr)
@@ -129,8 +127,6 @@ func (t *Term) Run() (int, error) {
 			}
 		}
 	}
-
-	return status, nil
 }
 
 // Println prints a line to the terminal.
@@ -158,10 +154,10 @@ func (t *Term) promptForInput() (string, error) {
 func (t *Term) handleExit() (int, error) {
 	fullHistoryFile, err := config.GetConfigFilePath(historyFile)
 	if err != nil {
-		fmt.Println("Error saving history file:", err)
+		fmt.Println("Error saving history file: ", err)
 	} else {
 		if f, err := os.OpenFile(fullHistoryFile, os.O_RDWR, 0666); err == nil {
-			_, err := t.line.WriteHistory(f)
+			_, err = t.line.WriteHistory(f)
 			if err != nil {
 				fmt.Println("readline history error: ", err)
 			}
@@ -183,8 +179,7 @@ func (t *Term) handleExit() (int, error) {
 			answer = strings.ToLower(strings.TrimSpace(answer))
 			kill = (answer != "n" && answer != "no")
 		}
-		err = t.client.Detach(kill)
+		if err := t.client.Detach(kill); err != nil {
-		if err != nil {
 			return 1, err
 		}
 	}