forked from googlecodelabs/tools
/
parse.go
70 lines (62 loc) · 1.83 KB
/
parse.go
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// Copyright 2016 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package parser
import (
"fmt"
"io"
"sync"
"github.com/googlecodelabs/tools/claat/types"
)
// ParseFunc parses source r into a Codelab for the specified environment env.
type ParseFunc func(r io.Reader) (*types.Codelab, error)
var (
parsersMu sync.Mutex // guards parsers
parsers = make(map[string]ParseFunc)
)
// Register registers a new parser f under specified name.
// It panics if another parser is already registered under the same name.
func Register(name string, f ParseFunc) {
parsersMu.Lock()
defer parsersMu.Unlock()
if _, exists := parsers[name]; exists {
panic(fmt.Sprintf("parser %q already registered", name))
}
parsers[name] = f
}
// Parsers returns a slice of all registered parser names.
func Parsers() []string {
parsersMu.Lock()
defer parsersMu.Unlock()
p := make([]string, 0, len(parsers))
for k := range parsers {
p = append(p, k)
}
return p
}
// Parse parses source r into a Codelab using a parser registered with
// the specified name.
func Parse(name string, r io.Reader) (*types.Codelab, error) {
parsersMu.Lock()
p, ok := parsers[name]
parsersMu.Unlock()
if !ok {
return nil, fmt.Errorf("no parser named %q", name)
}
c, err := p(r)
if err != nil {
return nil, err
}
c.URL = c.ID
return c, err
}