Source file based relative linking

ala GitHub repository markdown for both md files and non-md files

Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au>

helpers/content.go

@@ -43,27 +43,29 @@ var SummaryDivider = []byte("<!--more-->")
 
 // Blackfriday holds configuration values for Blackfriday rendering.
 type Blackfriday struct {
-	Smartypants     bool
-	AngledQuotes    bool
-	Fractions       bool
-	HrefTargetBlank bool
-	SmartDashes     bool
-	LatexDashes     bool
-	PlainIDAnchors  bool
-	Extensions      []string
-	ExtensionsMask  []string
+	Smartypants             bool
+	AngledQuotes            bool
+	Fractions               bool
+	HrefTargetBlank         bool
+	SmartDashes             bool
+	LatexDashes             bool
+	PlainIDAnchors          bool
+	SourceRelativeLinksEval bool
+	Extensions              []string
+	ExtensionsMask          []string
 }
 
 // NewBlackfriday creates a new Blackfriday filled with site config or some sane defaults
 func NewBlackfriday() *Blackfriday {
 	combinedParam := map[string]interface{}{
-		"smartypants":     true,
-		"angledQuotes":    false,
-		"fractions":       true,
-		"hrefTargetBlank": false,
-		"smartDashes":     true,
-		"latexDashes":     true,
-		"plainIDAnchors":  false,
+		"smartypants":         true,
+		"angledQuotes":        false,
+		"fractions":           true,
+		"hrefTargetBlank":     false,
+		"smartDashes":         true,
+		"latexDashes":         true,
+		"plainIDAnchors":      false,
+		"sourceRelativeLinks": false,
 	}
 
 	siteParam := viper.GetStringMap("blackfriday")
@@ -198,7 +200,9 @@ func GetHTMLRenderer(defaultFlags int, ctx *RenderingContext) blackfriday.Render
 	}
 
 	return &HugoHtmlRenderer{
-		blackfriday.HtmlRendererWithParameters(htmlFlags, "", "", renderParameters),
+		FileResolver: ctx.FileResolver,
+		LinkResolver: ctx.LinkResolver,
+		Renderer:     blackfriday.HtmlRendererWithParameters(htmlFlags, "", "", renderParameters),
 	}
 }
 
@@ -329,11 +333,13 @@ func ExtractTOC(content []byte) (newcontent []byte, toc []byte) {
 // RenderingContext holds contextual information, like content and configuration,
 // for a given content renderin.g
 type RenderingContext struct {
-	Content    []byte
-	PageFmt    string
-	DocumentID string
-	Config     *Blackfriday
-	configInit sync.Once
+	Content      []byte
+	PageFmt      string
+	DocumentID   string
+	Config       *Blackfriday
+	FileResolver FileResolverFunc
+	LinkResolver LinkResolverFunc
+	configInit   sync.Once
 }
 
 func (c *RenderingContext) getConfig() *Blackfriday {

helpers/content_renderer.go

@@ -19,12 +19,18 @@ import (
 
 	"github.com/miekg/mmark"
 	"github.com/russross/blackfriday"
+	jww "github.com/spf13/jwalterweatherman"
 	"github.com/spf13/viper"
 )
 
+type LinkResolverFunc func(ref string) (string, error)
+type FileResolverFunc func(ref string) (string, error)
+
 // Wraps a blackfriday.Renderer, typically a blackfriday.Html
 // Enabling Hugo to customise the rendering experience
 type HugoHtmlRenderer struct {
+	FileResolver FileResolverFunc
+	LinkResolver LinkResolverFunc
 	blackfriday.Renderer
 }
 
@@ -38,6 +44,33 @@ func (renderer *HugoHtmlRenderer) BlockCode(out *bytes.Buffer, text []byte, lang
 	}
 }
 
+func (renderer *HugoHtmlRenderer) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
+	if renderer.LinkResolver == nil || bytes.HasPrefix(link, []byte("{@{@HUGOSHORTCODE")) {
+		// Use the blackfriday built in Link handler
+		renderer.Renderer.Link(out, link, title, content)
+	} else {
+		newLink, err := renderer.LinkResolver(string(link))
+		if err != nil {
+			newLink = string(link)
+			jww.ERROR.Printf("LinkResolver: %s", err)
+		}
+		renderer.Renderer.Link(out, []byte(newLink), title, content)
+	}
+}
+func (renderer *HugoHtmlRenderer) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
+	if renderer.FileResolver == nil || bytes.HasPrefix(link, []byte("{@{@HUGOSHORTCODE")) {
+		// Use the blackfriday built in Image handler
+		renderer.Renderer.Image(out, link, title, alt)
+	} else {
+		newLink, err := renderer.FileResolver(string(link))
+		if err != nil {
+			newLink = string(link)
+			jww.ERROR.Printf("FileResolver: %s", err)
+		}
+		renderer.Renderer.Image(out, []byte(newLink), title, alt)
+	}
+}
+
 // Wraps a mmark.Renderer, typically a mmark.html
 // Enabling Hugo to customise the rendering experience
 type HugoMmarkHtmlRenderer struct {