Merge pull request urfave#2074 from dearchap/issue_2066

Fix:(issue_2066) Remove dependency on golang flag library

Author: dearchap

command.go

@@ -0,0 +1,207 @@
+package cli
+
+import (
+	"fmt"
+	"strings"
+)
+
+const (
+	providedButNotDefinedErrMsg = "flag provided but not defined: -"
+	argumentNotProvidedErrMsg   = "flag needs an argument: "
+)
+
+// flagFromError tries to parse a provided flag from an error message. If the
+// parsing fails, it returns the input error and an empty string
+func flagFromError(err error) (string, error) {
+	errStr := err.Error()
+	trimmed := strings.TrimPrefix(errStr, providedButNotDefinedErrMsg)
+	if errStr == trimmed {
+		return "", err
+	}
+	return trimmed, nil
+}
+
+func (cmd *Command) parseFlags(args Args) (Args, error) {
+	tracef("parsing flags from arguments %[1]q (cmd=%[2]q)", args, cmd.Name)
+
+	cmd.setFlags = map[Flag]struct{}{}
+	cmd.appliedFlags = cmd.allFlags()
+
+	tracef("walking command lineage for persistent flags (cmd=%[1]q)", cmd.Name)
+
+	for pCmd := cmd.parent; pCmd != nil; pCmd = pCmd.parent {
+		tracef(
+			"checking ancestor command=%[1]q for persistent flags (cmd=%[2]q)",
+			pCmd.Name, cmd.Name,
+		)
+
+		for _, fl := range pCmd.Flags {
+			flNames := fl.Names()
+
+			pfl, ok := fl.(LocalFlag)
+			if !ok || pfl.IsLocal() {
+				tracef("skipping non-persistent flag %[1]q (cmd=%[2]q)", flNames, cmd.Name)
+				continue
+			}
+
+			tracef(
+				"checking for applying persistent flag=%[1]q pCmd=%[2]q (cmd=%[3]q)",
+				flNames, pCmd.Name, cmd.Name,
+			)
+
+			applyPersistentFlag := true
+
+			for _, name := range flNames {
+				if cmd.lFlag(name) != nil {
+					applyPersistentFlag = false
+					break
+				}
+			}
+
+			if !applyPersistentFlag {
+				tracef("not applying as persistent flag=%[1]q (cmd=%[2]q)", flNames, cmd.Name)
+				continue
+			}
+
+			tracef("applying as persistent flag=%[1]q (cmd=%[2]q)", flNames, cmd.Name)
+
+			tracef("appending to applied flags flag=%[1]q (cmd=%[2]q)", flNames, cmd.Name)
+			cmd.appliedFlags = append(cmd.appliedFlags, fl)
+		}
+	}
+
+	tracef("parsing flags iteratively tail=%[1]q (cmd=%[2]q)", args.Tail(), cmd.Name)
+	defer tracef("done parsing flags (cmd=%[1]q)", cmd.Name)
+
+	posArgs := []string{}
+	for rargs := args.Slice(); len(rargs) > 0; rargs = rargs[1:] {
+		tracef("rearrange:1 (cmd=%[1]q) %[2]q", cmd.Name, rargs)
+
+		firstArg := strings.TrimSpace(rargs[0])
+		if len(firstArg) == 0 {
+			break
+		}
+
+		// stop parsing once we see a "--"
+		if firstArg == "--" {
+			posArgs = append(posArgs, rargs[1:]...)
+			return &stringSliceArgs{posArgs}, nil
+		}
+
+		// handle positional args
+		if firstArg[0] != '-' {
+			// positional argument probably
+			tracef("rearrange-3 (cmd=%[1]q) check %[2]q", cmd.Name, firstArg)
+
+			// if there is a command by that name let the command handle the
+			// rest of the parsing
+			if cmd.Command(firstArg) != nil {
+				posArgs = append(posArgs, rargs...)
+				return &stringSliceArgs{posArgs}, nil
+			}
+
+			posArgs = append(posArgs, firstArg)
+			continue
+		}
+
+		numMinuses := 1
+		// this is same as firstArg == "-"
+		if len(firstArg) == 1 {
+			posArgs = append(posArgs, firstArg)
+			break
+		}
+
+		shortOptionHandling := cmd.useShortOptionHandling()
+
+		// stop parsing -- as short flags
+		if firstArg[1] == '-' {
+			numMinuses++
+			shortOptionHandling = false
+		}
+
+		tracef("parseFlags (shortOptionHandling=%[1]q)", shortOptionHandling)
+
+		flagName := firstArg[numMinuses:]
+		flagVal := ""
+		tracef("flagName:1 (fName=%[1]q)", flagName)
+		if index := strings.Index(flagName, "="); index != -1 {
+			flagVal = flagName[index+1:]
+			flagName = flagName[:index]
+		}
+
+		tracef("flagName:2 (fName=%[1]q) (fVal=%[2]q)", flagName, flagVal)
+
+		f := cmd.lookupFlag(flagName)
+		// found a flag matching given flagName
+		if f != nil {
+			tracef("Trying flag type (fName=%[1]q) (type=%[2]T)", flagName, f)
+			if fb, ok := f.(boolFlag); ok && fb.IsBoolFlag() {
+				if flagVal == "" {
+					flagVal = "true"
+				}
+				tracef("parse Apply bool flag (fName=%[1]q) (fVal=%[2]q)", flagName, flagVal)
+				if err := cmd.set(flagName, f, flagVal); err != nil {
+					return &stringSliceArgs{posArgs}, err
+				}
+				continue
+			}
+
+			tracef("processing non bool flag (fName=%[1]q)", flagName)
+			// not a bool flag so need to get the next arg
+			if flagVal == "" {
+				if len(rargs) == 1 {
+					return &stringSliceArgs{posArgs}, fmt.Errorf("%s%s", argumentNotProvidedErrMsg, firstArg)
+				}
+				flagVal = rargs[1]
+				rargs = rargs[1:]
+			}
+
+			tracef("setting non bool flag (fName=%[1]q) (fVal=%[2]q)", flagName, flagVal)
+			if err := cmd.set(flagName, f, flagVal); err != nil {
+				return &stringSliceArgs{posArgs}, err
+			}
+
+			continue
+		}
+
+		// no flag lookup found and short handling is disabled
+		if !shortOptionHandling {
+			return &stringSliceArgs{posArgs}, fmt.Errorf("%s%s", providedButNotDefinedErrMsg, flagName)
+		}
+
+		// try to split the flags
+		for index, c := range flagName {
+			tracef("processing flag (fName=%[1]q)", string(c))
+			if sf := cmd.lookupFlag(string(c)); sf == nil {
+				return &stringSliceArgs{posArgs}, fmt.Errorf("%s%s", providedButNotDefinedErrMsg, flagName)
+			} else if fb, ok := sf.(boolFlag); ok && fb.IsBoolFlag() {
+				fv := flagVal
+				if index == (len(flagName)-1) && flagVal == "" {
+					fv = "true"
+				}
+				if fv == "" {
+					fv = "true"
+				}
+				if err := cmd.set(flagName, sf, fv); err != nil {
+					tracef("processing flag.2 (fName=%[1]q)", string(c))
+					return &stringSliceArgs{posArgs}, err
+				}
+			} else if index == len(flagName)-1 { // last flag can take an arg
+				if flagVal == "" {
+					if len(rargs) == 1 {
+						return &stringSliceArgs{posArgs}, fmt.Errorf("%s%s", argumentNotProvidedErrMsg, string(c))
+					}
+					flagVal = rargs[1]
+				}
+				tracef("parseFlags (flagName %[1]q) (flagVal %[2]q)", flagName, flagVal)
+				if err := cmd.set(flagName, sf, flagVal); err != nil {
+					tracef("processing flag.4 (fName=%[1]q)", string(c))
+					return &stringSliceArgs{posArgs}, err
+				}
+			}
+		}
+	}
+
+	tracef("returning-2 (cmd=%[1]q) args %[2]q", cmd.Name, posArgs)
+	return &stringSliceArgs{posArgs}, nil
+}