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// Copyright (C) 2017-2018, 2020 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
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package libfastimport
import (
"io"
"strings"
"git.lukeshu.com/go/libfastimport/textproto"
"github.com/pkg/errors"
)
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:
parser_commentCmds[prefix] = cmd
default:
panic(errors.Errorf("invalid cmdClass: %d", cmd.fiCmdClass()))
}
}
var parser_regular func(line string) func(fiReader) (Cmd, error)
var parser_comment func(line string) func(fiReader) (Cmd, error)
func parser_compile(cmds map[string]Cmd) func(line string) func(fiReader) (Cmd, error) {
// This assumes that 2 characters is enough to uniquely
// identify a command, and that "#" is the only one-character
// command.
ch2map := make(map[string]string, len(cmds))
for prefix := range cmds {
var ch2 string
if len(prefix) < 2 {
if prefix != "#" {
panic("the assumptions of parser_compile are invalid, it must be rewritten")
}
ch2 = prefix
} else {
ch2 = prefix[:2]
}
if _, dup := ch2map[ch2]; dup {
panic("the assumptions of parser_compile are invalid, it must be rewritten")
}
ch2map[ch2] = prefix
}
return func(line string) func(fiReader) (Cmd, error) {
n := 2
if strings.HasPrefix(line, "#") {
n = 1
}
if len(line) < n {
return nil
}
prototype := cmds[ch2map[line[:n]]]
if prototype == nil {
return nil
}
return prototype.fiCmdRead
}
}
type parser struct {
fir *textproto.FIReader
inCommit bool
buf_line *string
buf_err error
ret_cmd chan Cmd
ret_err error
}
func newParser(fir *textproto.FIReader) *parser {
if parser_regular == nil {
parser_regular = parser_compile(parser_regularCmds)
}
if parser_comment == nil {
parser_comment = parser_compile(parser_commentCmds)
}
ret := &parser{
fir: fir,
ret_cmd: make(chan Cmd),
}
go func() {
ret.ret_err = ret.parse()
close(ret.ret_cmd)
}()
return ret
}
func (p *parser) ReadCmd() (Cmd, error) {
cmd, ok := <-p.ret_cmd
if !ok {
return nil, p.ret_err
}
return cmd, nil
}
func (p *parser) parse() error {
for {
line, err := p.PeekLine()
if err != nil {
if err == io.EOF && p.inCommit {
p.ret_cmd <- CmdCommitEnd{}
}
return err
}
subparser := parser_regular(line)
if subparser == nil {
return UnsupportedCommand(line)
}
cmd, err := subparser(p)
if err != nil {
return err
}
switch cmd.fiCmdClass() {
case cmdClassCommand:
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()))
}
p.ret_cmd <- cmd
}
}
func (p *parser) PeekLine() (string, error) {
for p.buf_line == nil && p.buf_err == nil {
var line string
line, p.buf_err = p.fir.ReadLine()
p.buf_line = &line
if p.buf_err != nil {
return *p.buf_line, p.buf_err
}
subparser := parser_comment(line)
if subparser != nil {
var cmd Cmd
cmd, p.buf_err = subparser(p)
if p.buf_err != nil {
return "", p.buf_err
}
p.ret_cmd <- cmd
}
}
return *p.buf_line, p.buf_err
}
func (p *parser) ReadLine() (string, error) {
line, err := p.PeekLine()
p.buf_line = nil
p.buf_err = nil
return line, err
}
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