Tidy up cmdClass

6 files changed, 46 insertions, 54 deletions

diff --git a/backend.go b/backend.go
index 0486e98..c91d0ac 100644
--- a/backend.go
+++ b/backend.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2017-2018  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2017-2018, 2021  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -89,17 +89,11 @@ func (b *Backend) Do(cmd Cmd) error {
 		return b.err
 	}
 
-	switch cmd.fiCmdClass() {
-	case cmdClassCommand:
+	switch {
+	case !cmdIs(cmd, cmdClassInCommit):
 		_, b.inCommit = cmd.(CmdCommit)
-	case cmdClassCommit:
-		if !b.inCommit {
-			panic(errors.Errorf("Cannot issue commit sub-command outside of a commit: %[1]T(%#[1]v)", cmd))
-		}
-	case cmdClassComment:
-		/* do nothing */
-	default:
-		panic(errors.Errorf("invalid cmdClass: %d", cmd.fiCmdClass()))
+	case !b.inCommit && !cmdIs(cmd, cmdClassCommand):
+		panic(errors.Errorf("Cannot issue commit sub-command outside of a commit: %[1]T(%#[1]v)", cmd))
 	}
 
 	err := cmd.fiCmdWrite(b.fastImportWrite)
diff --git a/cmd.go b/cmd.go
index 1665081..d1358a8 100644
--- a/cmd.go
+++ b/cmd.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2017-2018  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2017-2018, 2021  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -41,10 +41,11 @@ type fiWriter interface {
 type cmdClass int
 
 const (
-	cmdClassCommand cmdClass = 1 // may be a top-level command
-	cmdClassCommit  cmdClass = 2 // may be used within in a commit
+	cmdClassCommand   cmdClass = 1 << iota // can be a top-level command
+	cmdClassInCommit                       // can be used within in a commit
+	cmdClassInCommand                      // can be used in-between lines of another multi-line command
 
-	cmdClassComment cmdClass = cmdClassCommand | cmdClassCommit
+	cmdClassComment = cmdClassCommand | cmdClassInCommit | cmdClassInCommand // "can be used anywhere in the stream that comments are accepted"
 )
 
 // Cmd is a command that may be found in a fast-import stream.
@@ -53,3 +54,7 @@ type Cmd interface {
 	fiCmdWrite(fiWriter) error
 	fiCmdClass() cmdClass
 }
+
+func cmdIs(cmd Cmd, class cmdClass) bool {
+	return cmd.fiCmdClass()&class != 0
+}
diff --git a/cmd_command.go b/cmd_command.go
index ff74f80..a958b60 100644
--- a/cmd_command.go
+++ b/cmd_command.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2017-2018  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2017-2018, 2021  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -119,7 +119,7 @@ func (CmdCommit) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 // Backend.
 type CmdCommitEnd struct{}
 
-func (CmdCommitEnd) fiCmdClass() cmdClass                { return cmdClassCommit }
+func (CmdCommitEnd) fiCmdClass() cmdClass                { return cmdClassInCommit }
 func (CmdCommitEnd) fiCmdWrite(fiw fiWriter) error       { return nil }
 func (CmdCommitEnd) fiCmdRead(fir fiReader) (Cmd, error) { panic("not reached") }
 
diff --git a/cmd_comment.go b/cmd_comment.go
index c0325b4..2124c8e 100644
--- a/cmd_comment.go
+++ b/cmd_comment.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2017-2018  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2017-2018, 2021  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -22,6 +22,10 @@ import (
 	"github.com/pkg/errors"
 )
 
+// This file deals with comments, and with commands for which the
+// specification says (or said) that the command "can be used anywhere
+// in the stream that comments are accepted".
+
 // comment /////////////////////////////////////////////////////////////////////
 
 // CmdComment is a comment line; not a real command.
@@ -105,19 +109,17 @@ type CmdLs struct {
 	Path    Path
 }
 
-// If you're thinking "but wait, parser_registerCmd will see CmdLs as
-// cmdClassCommit, not cmdClassComment, that means it won't be allowed
-// embedded inside other commands! (while still allowing it both
-// inside and outside of a commit)", you're absolutely correct.
-// That's the desired behavior.  It's a happy accident that the little
-// fiCmdClass hack works out that way, instead of having to add even
-// more complexity.
-
 func (c CmdLs) fiCmdClass() cmdClass {
+	// As of git v2.21, the docs say this is cmdClassComment, but
+	// the actual code disagrees.
 	if c.DataRef == "" {
-		return cmdClassCommit
+		// Yeah, this will give slightly misleading info to
+		// parser_registerCmd(), but that's OK,
+		// parser_registerCmd() only really cares about the
+		// cmdClassInCommand bit.
+		return cmdClassInCommit
 	}
-	return cmdClassComment
+	return cmdClassCommand | cmdClassInCommit
 }
 func (c CmdLs) fiCmdWrite(fiw fiWriter) error {
 	if c.DataRef == "" {
diff --git a/cmd_commit.go b/cmd_incommit.go
index 170c511..f58e59f 100644
--- a/cmd_commit.go
+++ b/cmd_incommit.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2017-2018  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2017-2018, 2021  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -37,7 +37,7 @@ type FileModify struct {
 	DataRef string
 }
 
-func (o FileModify) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o FileModify) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o FileModify) fiCmdWrite(fiw fiWriter) error {
 	return fiw.WriteLine("M", o.Mode, o.DataRef, o.Path)
 }
@@ -98,7 +98,7 @@ type FileModifyInline struct {
 	Data string
 }
 
-func (o FileModifyInline) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o FileModifyInline) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o FileModifyInline) fiCmdWrite(fiw fiWriter) error {
 	ez := &ezfiw{fiw: fiw}
 	ez.WriteLine("M", o.Mode, "inline", o.Path)
@@ -115,7 +115,7 @@ type FileDelete struct {
 	Path Path
 }
 
-func (o FileDelete) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o FileDelete) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o FileDelete) fiCmdWrite(fiw fiWriter) error {
 	return fiw.WriteLine("D", o.Path)
 }
@@ -138,7 +138,7 @@ type FileCopy struct {
 	Dst Path
 }
 
-func (o FileCopy) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o FileCopy) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o FileCopy) fiCmdWrite(fiw fiWriter) error {
 	return fiw.WriteLine("C", o.Src, o.Dst)
 }
@@ -158,7 +158,7 @@ type FileRename struct {
 	Dst string
 }
 
-func (o FileRename) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o FileRename) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o FileRename) fiCmdWrite(fiw fiWriter) error {
 	return fiw.WriteLine("R", o.Src, o.Dst)
 }
@@ -175,7 +175,7 @@ func (FileRename) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 // CmdCommit.
 type FileDeleteAll struct{}
 
-func (o FileDeleteAll) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o FileDeleteAll) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o FileDeleteAll) fiCmdWrite(fiw fiWriter) error {
 	return fiw.WriteLine("deleteall")
 }
@@ -203,7 +203,7 @@ type NoteModify struct {
 	DataRef   string
 }
 
-func (o NoteModify) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o NoteModify) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o NoteModify) fiCmdWrite(fiw fiWriter) error {
 	return fiw.WriteLine("N", o.DataRef, o.CommitIsh)
 }
@@ -257,7 +257,7 @@ type NoteModifyInline struct {
 	Data      string
 }
 
-func (o NoteModifyInline) fiCmdClass() cmdClass { return cmdClassCommit }
+func (o NoteModifyInline) fiCmdClass() cmdClass { return cmdClassInCommit }
 func (o NoteModifyInline) fiCmdWrite(fiw fiWriter) error {
 	ez := &ezfiw{fiw: fiw}
 	ez.WriteLine("N", "inline", o.CommitIsh)
diff --git a/parse_fastimport.go b/parse_fastimport.go
index 491788b..7f84dfd 100644
--- a/parse_fastimport.go
+++ b/parse_fastimport.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2017-2018, 2020  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2017-2018, 2020-2021  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -27,13 +27,10 @@ var parser_regularCmds = make(map[string]Cmd)
 var parser_commentCmds = make(map[string]Cmd)
 
 func parser_registerCmd(prefix string, cmd Cmd) {
-	switch cmd.fiCmdClass() {
-	case cmdClassCommand, cmdClassCommit:
-		parser_regularCmds[prefix] = cmd
-	case cmdClassComment:
+	if cmdIs(cmd, cmdClassInCommand) {
 		parser_commentCmds[prefix] = cmd
-	default:
-		panic(errors.Errorf("invalid cmdClass: %d", cmd.fiCmdClass()))
+	} else {
+		parser_regularCmds[prefix] = cmd
 	}
 }
 
@@ -133,20 +130,14 @@ func (p *parser) parse() error {
 			return err
 		}
 
-		switch cmd.fiCmdClass() {
-		case cmdClassCommand:
+		switch {
+		case !cmdIs(cmd, cmdClassInCommit):
 			if p.inCommit {
 				p.ret_cmd <- CmdCommitEnd{}
 			}
 			_, p.inCommit = cmd.(CmdCommit)
-		case cmdClassCommit:
-			if !p.inCommit {
-				return errors.Errorf("Got in-commit-only command outside of a commit: %[1]T(%#[1]v)", cmd)
-			}
-		case cmdClassComment:
-			/* do nothing */
-		default:
-			panic(errors.Errorf("invalid cmdClass: %d", cmd.fiCmdClass()))
+		case !p.inCommit && !cmdIs(cmd, cmdClassCommand):
+			return errors.Errorf("Got in-commit-only command outside of a commit: %[1]T(%#[1]v)", cmd)
 		}
 
 		p.ret_cmd <- cmd