1 files changed, 126 insertions, 0 deletions
diff --git a/tpl/partials/partials.go b/tpl/partials/partials.go
new file mode 100644
index 000000000..d6e9fc9c5
--- /dev/null
+++ b/tpl/partials/partials.go
@@ -0,0 +1,126 @@
+// Copyright 2017 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 partials
+
+import (
+	"fmt"
+	"html/template"
+	"strings"
+	"sync"
+	texttemplate "text/template"
+
+	bp "github.com/gohugoio/hugo/bufferpool"
+	"github.com/gohugoio/hugo/deps"
+)
+
+var TestTemplateProvider deps.ResourceProvider
+
+// partialCache represents a cache of partials protected by a mutex.
+type partialCache struct {
+	sync.RWMutex
+	p map[string]interface{}
+}
+
+// New returns a new instance of the templates-namespaced template functions.
+func New(deps *deps.Deps) *Namespace {
+	return &Namespace{
+		deps:           deps,
+		cachedPartials: partialCache{p: make(map[string]interface{})},
+	}
+}
+
+// Namespace provides template functions for the "templates" namespace.
+type Namespace struct {
+	deps           *deps.Deps
+	cachedPartials partialCache
+}
+
+// Include executes the named partial and returns either a string,
+// when the partial is a text/template, or template.HTML when html/template.
+func (ns *Namespace) Include(name string, contextList ...interface{}) (interface{}, error) {
+	if strings.HasPrefix("partials/", name) {
+		name = name[8:]
+	}
+	var context interface{}
+
+	if len(contextList) == 0 {
+		context = nil
+	} else {
+		context = contextList[0]
+	}
+
+	for _, n := range []string{"partials/" + name, "theme/partials/" + name} {
+		templ := ns.deps.Tmpl.Lookup(n)
+		if templ == nil {
+			// For legacy reasons.
+			templ = ns.deps.Tmpl.Lookup(n + ".html")
+		}
+		if templ != nil {
+			b := bp.GetBuffer()
+			defer bp.PutBuffer(b)
+
+			if err := templ.Execute(b, context); err != nil {
+				return "", err
+			}
+
+			if _, ok := templ.Template.(*texttemplate.Template); ok {
+				return b.String(), nil
+			}
+
+			return template.HTML(b.String()), nil
+
+		}
+	}
+
+	return "", fmt.Errorf("Partial %q not found", name)
+}
+
+// getCached executes and caches partial templates.  An optional variant
+// string parameter (a string slice actually, but be only use a variadic
+// argument to make it optional) can be passed so that a given partial can have
+// multiple uses. The cache is created with name+variant as the key.
+func (ns *Namespace) getCached(name string, context interface{}, variant ...string) (interface{}, error) {
+	key := name
+	if len(variant) > 0 {
+		for i := 0; i < len(variant); i++ {
+			key += variant[i]
+		}
+	}
+	return ns.getOrCreate(key, name, context)
+}
+
+func (ns *Namespace) getOrCreate(key, name string, context interface{}) (p interface{}, err error) {
+	var ok bool
+
+	ns.cachedPartials.RLock()
+	p, ok = ns.cachedPartials.p[key]
+	ns.cachedPartials.RUnlock()
+
+	if ok {
+		return
+	}
+
+	ns.cachedPartials.Lock()
+	if p, ok = ns.cachedPartials.p[key]; !ok {
+		ns.cachedPartials.Unlock()
+		p, err = ns.Include(name, context)
+
+		ns.cachedPartials.Lock()
+		ns.cachedPartials.p[key] = p
+
+	}
+	ns.cachedPartials.Unlock()
+
+	return
+}