Bug 457810 - Speculatively load stylesheets from preloading. r=mrbkap, sr=bzbarsky

parser/htmlparser/src/nsParser.cpp

@@ -71,6 +71,9 @@
 #include "nsDataHashtable.h"
 #include "nsIThreadPool.h"
 #include "nsXPCOMCIDInternal.h"
+#include "nsICSSStyleSheet.h"
+#include "nsICSSLoaderObserver.h"
+#include "nsICSSLoader.h"
 
 #ifdef MOZ_VIEW_SOURCE
 #include "nsViewSourceHTML.h"
@@ -221,7 +224,7 @@ public:
   nsresult StartParsing(nsParser *aParser);
   void StopParsing(PRBool aFromDocWrite);
 
-  enum PrefetchType { SCRIPT, STYLESHEET, IMAGE };
+  enum PrefetchType { NONE, SCRIPT, STYLESHEET, IMAGE };
   struct PrefetchEntry {
     PrefetchType type;
     nsString uri;
@@ -291,6 +294,21 @@ private:
   PRBool mTerminated;
 };
 
+/**
+ * Used if we need to pass an nsICSSLoaderObserver as parameter,
+ * but don't really need its services
+ */
+class nsDummyCSSLoaderObserver : public nsICSSLoaderObserver {
+public:
+  NS_IMETHOD
+  StyleSheetLoaded(nsICSSStyleSheet* aSheet, PRBool aWasAlternate, nsresult aStatus) {
+      return NS_OK;
+  }
+  NS_DECL_ISUPPORTS
+};
+
+NS_IMPL_ISUPPORTS1(nsDummyCSSLoaderObserver, nsICSSLoaderObserver)
+
 class nsPreloadURIs : public nsIRunnable {
 public:
   nsPreloadURIs(nsAutoTArray<nsSpeculativeScriptThread::PrefetchEntry, 5> &aURIs,
@@ -343,10 +361,6 @@ nsPreloadURIs::PreloadURIs(const nsAutoTArray<nsSpeculativeScriptThread::Prefetc
     aScriptThread->GetPreloadedURIs();
   for (PRUint32 i = 0, e = aURIs.Length(); i < e; ++i) {
     const nsSpeculativeScriptThread::PrefetchEntry &pe = aURIs[i];
-    if (pe.type != nsSpeculativeScriptThread::SCRIPT) {
-      continue;
-    }
-
     nsCOMPtr<nsIURI> uri;
     nsresult rv = NS_NewURI(getter_AddRefs(uri), pe.uri, charset.get(), base);
     if (NS_FAILED(rv)) {
@@ -364,7 +378,15 @@ nsPreloadURIs::PreloadURIs(const nsAutoTArray<nsSpeculativeScriptThread::Prefetc
 
     alreadyPreloaded.Put(spec, PR_TRUE);
 
-    doc->ScriptLoader()->PreloadURI(uri, pe.charset, pe.elementType);
+    switch (pe.type) {
+      case nsSpeculativeScriptThread::SCRIPT:
+        doc->ScriptLoader()->PreloadURI(uri, pe.charset, pe.elementType);
+        break; 
+      case nsSpeculativeScriptThread::STYLESHEET:
+        nsCOMPtr<nsICSSLoaderObserver> obs = new nsDummyCSSLoaderObserver();
+        doc->CSSLoader()->LoadSheet(uri, doc->NodePrincipal(), obs);
+        break;
+    }
   }
 }
 
@@ -553,84 +575,68 @@ nsSpeculativeScriptThread::ProcessToken(CToken *aToken)
         nsAutoString src;
         nsAutoString elementType;
         nsAutoString charset;
-        PrefetchType ptype = SCRIPT;
+        nsAutoString href;
+        nsAutoString rel;
+        PrefetchType ptype = NONE;
 
         switch (tag) {
-#if 0 // TODO Support stylesheet and image preloading.
-          case eHTMLTag_link: {
-            // If this is a <link rel=stylesheet> find the src.
-            PRBool isRelStylesheet = PR_FALSE;
-            for (; i < attrs; ++i) {
-              CAttributeToken *attr = static_cast<CAttributeToken *>(mTokenizer->PopToken());
-              NS_ASSERTION(attr->GetTokenType() == eToken_attribute, "Weird token");
+          case eHTMLTag_link:
+              ptype = STYLESHEET;
+              break;
 
-              if (attr->GetKey().EqualsLiteral("rel")) {
-                if (!attr->GetValue().EqualsLiteral("stylesheet")) {
-                  IF_FREE(attr, &mTokenAllocator);
-                  break;
-                }
-                isRelStylesheet = PR_TRUE;
-              } else if (attr->GetKey().EqualsLiteral("src")) {
-                src.Assign(attr->GetValue());
-                if (isRelStylesheet) {
-                  IF_FREE(attr, &mTokenAllocator);
-                  break;
-                }
-              }
-
-              IF_FREE(attr, &mTokenAllocator);
-            }
-
-            if (isRelStylesheet && !src.IsEmpty()) {
-              AddToPrefetchList(src, STYLESHEET);
-            }
-            break;
-          }
-
-          case eHTMLTag_style:
-            ptype = STYLESHEET;
-            /* FALL THROUGH */
-          case eHTMLTag_img:
-            if (tag == eHTMLTag_img)
-              ptype = IMAGE;
-            /* FALL THROUGH */
-#endif
           case eHTMLTag_script:
-            if (tag == eHTMLTag_script)
               ptype = SCRIPT;
+              break;
 
-            for (; i < attrs; ++i) {
+          default:
+              break;
+        }
+
+        // We currently handle the following element/attribute combos :
+        //     <link rel="stylesheet" href= charset= type>
+        //     <script src= charset= type=>
+        if (ptype != NONE) {
+      
+            // loop over all attributes to extract relevant info
+            for (; i < attrs ; ++i) {
               CAttributeToken *attr = static_cast<CAttributeToken *>(mTokenizer->PopToken());
               NS_ASSERTION(attr->GetTokenType() == eToken_attribute, "Weird token");
-
+    
               if (attr->GetKey().EqualsLiteral("src")) {
                 src.Assign(attr->GetValue());
+              } else if (attr->GetKey().EqualsLiteral("href")) {
+                href.Assign(attr->GetValue());
+              } else if (attr->GetKey().EqualsLiteral("rel")) {
+                rel.Assign(attr->GetValue());
               } else if (attr->GetKey().EqualsLiteral("charset")) {
                 charset.Assign(attr->GetValue());
               } else if (attr->GetKey().EqualsLiteral("type")) {
                 elementType.Assign(attr->GetValue());
               }
+
               IF_FREE(attr, &mTokenAllocator);
             }
 
+            // ensure we have the right kind if it's a link-element
+            if (ptype == STYLESHEET) {
+              if (rel.EqualsLiteral("stylesheet")) {
+                src = href; // src is the important variable below
+              } else {
+                src.Truncate(); // clear src if wrong kind of link
+              }
+            }
+
+            // add to list if we have a valid src
             if (!src.IsEmpty()) {
               AddToPrefetchList(src, charset, elementType, ptype);
             }
-            break;
-
-          default:
-            break;
+        } else {
+            // Irrelevant tag, but pop and free all its attributes in any case
+            for (; i < attrs ; ++i) {
+              CToken *attr = mTokenizer->PopToken();
+              IF_FREE(attr, &mTokenAllocator);
+            }
         }
-
-        for (; i < attrs; ++i) {
-          CToken *attr = mTokenizer->PopToken();
-          if (!attr) {
-            break;
-          }
-          NS_ASSERTION(attr->GetTokenType() == eToken_attribute, "Weird token");
-          IF_FREE(attr, &mTokenAllocator);
-        }
-
         break;
       }