Introduce a new non-heap-allocated type for holding nsStringBuffer* in the HTML parser.

An innerHTML setter profile shows about 10% of the time being spent under nsHtml5HtmlAttributes::clear, mostly deleting nsStrings.

1 files changed, 18 insertions, 15 deletions

diff --git a/parser/html/nsHtml5ViewSourceUtils.cpp b/parser/html/nsHtml5ViewSourceUtils.cpp
index 4dd33fc05..b2f635bff 100644
--- a/parser/html/nsHtml5ViewSourceUtils.cpp
+++ b/parser/html/nsHtml5ViewSourceUtils.cpp
@@ -6,32 +6,35 @@
 #include "nsHtml5ViewSourceUtils.h"
 #include "nsHtml5AttributeName.h"
 #include "mozilla/Preferences.h"
-#include "mozilla/UniquePtr.h"
+#include "nsHtml5String.h"
 
 // static
 nsHtml5HtmlAttributes*
 nsHtml5ViewSourceUtils::NewBodyAttributes()
 {
   nsHtml5HtmlAttributes* bodyAttrs = new nsHtml5HtmlAttributes(0);
-  auto id = MakeUnique<nsString>(NS_LITERAL_STRING("viewsource"));
-  bodyAttrs->addAttribute(nsHtml5AttributeName::ATTR_ID, id.release(), -1);
+  nsHtml5String id = nsHtml5Portability::newStringFromLiteral("viewsource");
+  bodyAttrs->addAttribute(nsHtml5AttributeName::ATTR_ID, id, -1);
 
-  auto klass = MakeUnique<nsString>();
+  nsString klass;
   if (mozilla::Preferences::GetBool("view_source.wrap_long_lines", true)) {
-    klass->Append(NS_LITERAL_STRING("wrap "));
+    klass.Append(NS_LITERAL_STRING("wrap "));
   }
   if (mozilla::Preferences::GetBool("view_source.syntax_highlight", true)) {
-    klass->Append(NS_LITERAL_STRING("highlight"));
+    klass.Append(NS_LITERAL_STRING("highlight"));
   }
-  if (!klass->IsEmpty()) {
-    bodyAttrs->addAttribute(nsHtml5AttributeName::ATTR_CLASS, klass.release(), -1);
+  if (!klass.IsEmpty()) {
+    bodyAttrs->addAttribute(
+      nsHtml5AttributeName::ATTR_CLASS, nsHtml5String::FromString(klass), -1);
   }
 
   int32_t tabSize = mozilla::Preferences::GetInt("view_source.tab_size", 4);
   if (tabSize > 0) {
-    auto style = MakeUnique<nsString>(NS_LITERAL_STRING("-moz-tab-size: "));
-    style->AppendInt(tabSize);
-    bodyAttrs->addAttribute(nsHtml5AttributeName::ATTR_STYLE, style.release(), -1);
+    nsString style;
+    style.AssignASCII("-moz-tab-size: ");
+    style.AppendInt(tabSize);
+    bodyAttrs->addAttribute(
+      nsHtml5AttributeName::ATTR_STYLE, nsHtml5String::FromString(style), -1);
   }
 
   return bodyAttrs;
@@ -42,12 +45,12 @@ nsHtml5HtmlAttributes*
 nsHtml5ViewSourceUtils::NewLinkAttributes()
 {
   nsHtml5HtmlAttributes* linkAttrs = new nsHtml5HtmlAttributes(0);
-  nsString* rel = new nsString(NS_LITERAL_STRING("stylesheet"));
+  nsHtml5String rel = nsHtml5Portability::newStringFromLiteral("stylesheet");
   linkAttrs->addAttribute(nsHtml5AttributeName::ATTR_REL, rel, -1);
-  nsString* type = new nsString(NS_LITERAL_STRING("text/css"));
+  nsHtml5String type = nsHtml5Portability::newStringFromLiteral("text/css");
   linkAttrs->addAttribute(nsHtml5AttributeName::ATTR_TYPE, type, -1);
-  nsString* href = new nsString(
-      NS_LITERAL_STRING("resource://gre-resources/viewsource.css"));
+  nsHtml5String href = nsHtml5Portability::newStringFromLiteral(
+    "resource://gre-resources/viewsource.css");
   linkAttrs->addAttribute(nsHtml5AttributeName::ATTR_HREF, href, -1);
   return linkAttrs;
 }