diff options
Diffstat (limited to 'common/maps/scratch.go')
-rw-r--r-- | common/maps/scratch.go | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/common/maps/scratch.go b/common/maps/scratch.go new file mode 100644 index 000000000..7a3cd3748 --- /dev/null +++ b/common/maps/scratch.go @@ -0,0 +1,162 @@ +// Copyright 2019 The Hugo Authors. 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 maps + +import ( + "reflect" + "sort" + "sync" + + "github.com/gohugoio/hugo/common/collections" + "github.com/gohugoio/hugo/common/math" +) + +// Scratch is a writable context used for stateful operations in Page/Node rendering. +type Scratch struct { + values map[string]interface{} + mu sync.RWMutex +} + +// Scratcher provides a scratching service. +type Scratcher interface { + Scratch() *Scratch +} + +type scratcher struct { + s *Scratch +} + +func (s scratcher) Scratch() *Scratch { + return s.s +} + +// NewScratcher creates a new Scratcher. +func NewScratcher() Scratcher { + return scratcher{s: NewScratch()} +} + +// Add will, for single values, add (using the + operator) the addend to the existing addend (if found). +// Supports numeric values and strings. +// +// If the first add for a key is an array or slice, then the next value(s) will be appended. +func (c *Scratch) Add(key string, newAddend interface{}) (string, error) { + + var newVal interface{} + c.mu.RLock() + existingAddend, found := c.values[key] + c.mu.RUnlock() + if found { + var err error + + addendV := reflect.TypeOf(existingAddend) + + if addendV.Kind() == reflect.Slice || addendV.Kind() == reflect.Array { + newVal, err = collections.Append(existingAddend, newAddend) + if err != nil { + return "", err + } + } else { + newVal, err = math.DoArithmetic(existingAddend, newAddend, '+') + if err != nil { + return "", err + } + } + } else { + newVal = newAddend + } + c.mu.Lock() + c.values[key] = newVal + c.mu.Unlock() + return "", nil // have to return something to make it work with the Go templates +} + +// Set stores a value with the given key in the Node context. +// This value can later be retrieved with Get. +func (c *Scratch) Set(key string, value interface{}) string { + c.mu.Lock() + c.values[key] = value + c.mu.Unlock() + return "" +} + +// Delete deletes the given key. +func (c *Scratch) Delete(key string) string { + c.mu.Lock() + delete(c.values, key) + c.mu.Unlock() + return "" +} + +// Get returns a value previously set by Add or Set. +func (c *Scratch) Get(key string) interface{} { + c.mu.RLock() + val := c.values[key] + c.mu.RUnlock() + + return val +} + +// Values returns the raw backing map. Note that you should just use +// this method on the locally scoped Scratch instances you obtain via newScratch, not +// .Page.Scratch etc., as that will lead to concurrency issues. +func (c *Scratch) Values() map[string]interface{} { + c.mu.RLock() + defer c.mu.RUnlock() + return c.values +} + +// SetInMap stores a value to a map with the given key in the Node context. +// This map can later be retrieved with GetSortedMapValues. +func (c *Scratch) SetInMap(key string, mapKey string, value interface{}) string { + c.mu.Lock() + _, found := c.values[key] + if !found { + c.values[key] = make(map[string]interface{}) + } + + c.values[key].(map[string]interface{})[mapKey] = value + c.mu.Unlock() + return "" +} + +// GetSortedMapValues returns a sorted map previously filled with SetInMap. +func (c *Scratch) GetSortedMapValues(key string) interface{} { + c.mu.RLock() + + if c.values[key] == nil { + c.mu.RUnlock() + return nil + } + + unsortedMap := c.values[key].(map[string]interface{}) + c.mu.RUnlock() + var keys []string + for mapKey := range unsortedMap { + keys = append(keys, mapKey) + } + + sort.Strings(keys) + + sortedArray := make([]interface{}, len(unsortedMap)) + for i, mapKey := range keys { + sortedArray[i] = unsortedMap[mapKey] + } + + return sortedArray +} + +// NewScratch returns a new instance of Scratch. +func NewScratch() *Scratch { + return &Scratch{values: make(map[string]interface{})} +} |