hugolib: Cache the value of Page's RelPermalink

diff --git a/hugolib/page.go b/hugolib/page.go
index 8fce69b355768a606723385e5402323536f1f23f..7ca1662908adb332702ec92c64e2640b5590e878 100644 (file)
--- a/hugolib/page.go
+++ b/hugolib/page.go
@@ -189,7 +189,8 @@ type Page struct {
        RSSLink template.HTML
 
        URLPath
-       permalink *url.URL
+       permalink    *url.URL
+       relPermalink string
 
        paginator *Pager
 
@@ -213,6 +214,7 @@ type pageInit struct {
        plainWordsInit      sync.Once
        renderingConfigInit sync.Once
        pageURLInit         sync.Once
+       relPermalinkInit    sync.Once
 }
 
 // IsNode returns whether this is an item of one of the list types in Hugo,
@@ -927,34 +929,39 @@ func (p *Page) URL() string {
 }
 
 func (p *Page) RelPermalink() string {
-       link := p.getPermalink()
+       p.relPermalinkInit.Do(func() {
+               link := p.getPermalink()
 
-       if p.s.Info.canonifyURLs {
-               // replacements for relpermalink with baseURL on the form http://myhost.com/sub/ will fail later on
-               // have to return the URL relative from baseURL
-               relpath, err := helpers.GetRelativePath(link.String(), string(p.Site.BaseURL))
-               if err != nil {
-                       return ""
-               }
+               if p.s.Info.canonifyURLs {
+                       // replacements for relpermalink with baseURL on the form http://myhost.com/sub/ will fail later on
+                       // have to return the URL relative from baseURL
+                       relpath, err := helpers.GetRelativePath(link.String(), string(p.Site.BaseURL))
+                       if err != nil {
+                               return
+                       }
 
-               relpath = filepath.ToSlash(relpath)
+                       relpath = filepath.ToSlash(relpath)
 
-               if relpath[0] == '.' {
-                       relpath = relpath[1:]
-               }
+                       if relpath[0] == '.' {
+                               relpath = relpath[1:]
+                       }
+
+                       if !strings.HasPrefix(relpath, "/") {
+                               relpath = "/" + relpath
+                       }
 
-               if !strings.HasPrefix(relpath, "/") {
-                       relpath = "/" + relpath
+                       p.relPermalink = relpath
+                       return
                }
 
-               return relpath
-       }
+               link.Scheme = ""
+               link.Host = ""
+               link.User = nil
+               link.Opaque = ""
+               p.relPermalink = link.String()
+       })
 
-       link.Scheme = ""
-       link.Host = ""
-       link.User = nil
-       link.Opaque = ""
-       return link.String()
+       return p.relPermalink
 }
 
 var ErrHasDraftAndPublished = errors.New("both draft and published parameters were found in page's frontmatter")