125 lines
2.6 KiB
Go
125 lines
2.6 KiB
Go
// Copyright 2014 The Cayley Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package sexp
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// Defines a running session of the sexp query language.
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import (
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"encoding/json"
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"errors"
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"fmt"
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"sort"
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"github.com/google/cayley/graph"
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"github.com/google/cayley/query"
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)
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type Session struct {
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qs graph.QuadStore
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debug bool
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}
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func NewSession(qs graph.QuadStore) *Session {
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var s Session
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s.qs = qs
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return &s
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}
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func (s *Session) Debug(ok bool) {
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s.debug = ok
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}
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func (s *Session) Parse(input string) (query.ParseResult, error) {
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var parenDepth int
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for i, x := range input {
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if x == '(' {
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parenDepth++
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}
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if x == ')' {
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parenDepth--
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if parenDepth < 0 {
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min := 0
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if (i - 10) > min {
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min = i - 10
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}
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return query.ParseFail, fmt.Errorf("too many close parentheses at char %d: %s", i, input[min:i])
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}
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}
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}
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if parenDepth > 0 {
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return query.ParseMore, nil
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}
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if len(ParseString(input)) > 0 {
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return query.Parsed, nil
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}
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return query.ParseFail, errors.New("invalid syntax")
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}
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func (s *Session) Execute(input string, out chan interface{}, limit int) {
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it := BuildIteratorTreeForQuery(s.qs, input)
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newIt, changed := it.Optimize()
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if changed {
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it = newIt
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}
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if s.debug {
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b, err := json.MarshalIndent(it.Describe(), "", " ")
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if err != nil {
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fmt.Printf("failed to format description: %v", err)
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} else {
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fmt.Printf("%s", b)
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}
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}
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nResults := 0
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for graph.Next(it) {
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tags := make(map[string]graph.Value)
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it.TagResults(tags)
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out <- &tags
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nResults++
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if nResults > limit && limit != -1 {
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break
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}
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for it.NextPath() == true {
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tags := make(map[string]graph.Value)
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it.TagResults(tags)
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out <- &tags
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nResults++
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if nResults > limit && limit != -1 {
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break
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}
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}
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}
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close(out)
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}
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func (s *Session) Format(result interface{}) string {
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out := fmt.Sprintln("****")
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tags := result.(map[string]graph.Value)
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tagKeys := make([]string, len(tags))
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i := 0
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for k := range tags {
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tagKeys[i] = k
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i++
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}
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sort.Strings(tagKeys)
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for _, k := range tagKeys {
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if k == "$_" {
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continue
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}
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out += fmt.Sprintf("%s : %s\n", k, s.qs.NameOf(tags[k]))
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}
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return out
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}
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