Bug 1386103 (part 2, attempt 3) - Convert nsFixed[C]String uses to nsAuto[C]String. r=erahm.

caps/NullPrincipalURI.cpp

@@ -19,12 +19,10 @@
 //// NullPrincipalURI
 
 NullPrincipalURI::NullPrincipalURI()
-  : mPath(mPathBytes, ArrayLength(mPathBytes), ArrayLength(mPathBytes) - 1)
 {
 }
 
 NullPrincipalURI::NullPrincipalURI(const NullPrincipalURI& aOther)
-  : mPath(mPathBytes, ArrayLength(mPathBytes), ArrayLength(mPathBytes) - 1)
 {
   mPath.Assign(aOther.mPath);
 }
@@ -40,9 +38,9 @@ NullPrincipalURI::Init()
   nsresult rv = uuidgen->GenerateUUIDInPlace(&id);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  MOZ_ASSERT(mPathBytes == mPath.BeginWriting());
-
-  id.ToProvidedString(mPathBytes);
+  mPath.SetLength(NSID_LENGTH - 1); // -1 because NSID_LENGTH counts the '\0'
+  id.ToProvidedString(
+    *reinterpret_cast<char(*)[NSID_LENGTH]>(mPath.BeginWriting()));
 
   MOZ_ASSERT(mPath.Length() == NSID_LENGTH - 1);
   MOZ_ASSERT(strlen(mPath.get()) == NSID_LENGTH - 1);

caps/NullPrincipalURI.h

@@ -52,8 +52,7 @@ private:
 
   nsresult Init();
 
-  char mPathBytes[NSID_LENGTH];
-  nsFixedCString mPath;
+  nsAutoCStringN<NSID_LENGTH> mPath;
 };
 
 #endif // __NullPrincipalURI_h__

dom/indexedDB/ProfilerHelpers.h

@@ -37,7 +37,7 @@ namespace dom {
 namespace indexedDB {
 
 class MOZ_STACK_CLASS LoggingIdString final
-  : public nsAutoCString
+  : public nsAutoCStringN<NSID_LENGTH>
 {
 public:
   LoggingIdString()
@@ -62,8 +62,9 @@ public:
   {
     static_assert(NSID_LENGTH > 1, "NSID_LENGTH is set incorrectly!");
     static_assert(NSID_LENGTH <= kStorageSize,
-                  "nID string won't fit in our storage!");
-    MOZ_ASSERT(Capacity() > NSID_LENGTH);
+                  "nsID string won't fit in our storage!");
+    // Capacity() excludes the null terminator; NSID_LENGTH includes it.
+    MOZ_ASSERT(Capacity() + 1 == NSID_LENGTH);
 
     if (IndexedDatabaseManager::GetLoggingMode() !=
           IndexedDatabaseManager::Logging_Disabled) {

dom/ipc/ContentParent.cpp

@@ -1993,12 +1993,9 @@ ContentParent::LaunchSubprocess(ProcessPriority aInitialPriority /* = PROCESS_PR
   extraArgs.push_back(idStr);
   extraArgs.push_back(IsForBrowser() ? "-isForBrowser" : "-notForBrowser");
 
-  char boolBuf[1024];
-  char intBuf[1024];
-  char strBuf[1024];
-  nsFixedCString boolPrefs(boolBuf, 1024, 0);
-  nsFixedCString intPrefs(intBuf, 1024, 0);
-  nsFixedCString stringPrefs(strBuf, 1024, 0);
+  nsAutoCStringN<1024> boolPrefs;
+  nsAutoCStringN<1024> intPrefs;
+  nsAutoCStringN<1024> stringPrefs;
 
   size_t prefsLen;
   ContentPrefs::GetContentPrefs(&prefsLen);

dom/xul/templates/nsXULContentBuilder.cpp

@@ -600,8 +600,7 @@ nsXULContentBuilder::BuildContentFromTemplate(nsIContent *aTemplateNode,
             // given node.
             // SynchronizeUsingTemplate contains code used to update textnodes,
             // so make sure to modify both when changing this
-            char16_t attrbuf[128];
-            nsFixedString attrValue(attrbuf, ArrayLength(attrbuf), 0);
+            nsAutoString attrValue;
             tmplKid->GetAttr(kNameSpaceID_None, nsGkAtoms::value, attrValue);
             if (!attrValue.IsEmpty()) {
                 nsAutoString value;
@@ -737,11 +736,7 @@ nsXULContentBuilder::CopyAttributesToElement(nsIContent* aTemplateNode,
 
         // XXXndeakin ignore namespaces until bug 321182 is fixed
         if (attribName != nsGkAtoms::id && attribName != nsGkAtoms::uri) {
-            // Create a buffer here, because there's a chance that an
-            // attribute in the template is going to be an RDF URI, which is
-            // usually longish.
-            char16_t attrbuf[128];
-            nsFixedString attribValue(attrbuf, ArrayLength(attrbuf), 0);
+            nsAutoString attribValue;
             aTemplateNode->GetAttr(attribNameSpaceID, attribName, attribValue);
             if (!attribValue.IsEmpty()) {
                 nsAutoString value;
@@ -878,8 +873,7 @@ nsXULContentBuilder::SynchronizeUsingTemplate(nsIContent* aTemplateNode,
         // This code is similar to that in BuildContentFromTemplate
         if (tmplKid->NodeInfo()->Equals(nsGkAtoms::textnode,
                                         kNameSpaceID_XUL)) {
-            char16_t attrbuf[128];
-            nsFixedString attrValue(attrbuf, ArrayLength(attrbuf), 0);
+            nsAutoString attrValue;
             tmplKid->GetAttr(kNameSpaceID_None, nsGkAtoms::value, attrValue);
             if (!attrValue.IsEmpty()) {
                 nsAutoString value;

dom/xul/templates/nsXULContentUtils.cpp

@@ -255,8 +255,7 @@ nsXULContentUtils::GetResource(int32_t aNameSpaceID, const nsAString& aAttribute
 
     nsresult rv;
 
-    char16_t buf[256];
-    nsFixedString uri(buf, ArrayLength(buf), 0);
+    nsAutoStringN<256> uri;
     if (aNameSpaceID != kNameSpaceID_Unknown && aNameSpaceID != kNameSpaceID_None) {
         rv = nsContentUtils::NameSpaceManager()->GetNameSpaceURI(aNameSpaceID, uri);
         // XXX ignore failure; treat as "no namespace"

rdf/base/nsRDFContainer.cpp

@@ -687,8 +687,7 @@ RDFContainerImpl::GetNextValue(nsIRDFResource** aResult)
     }
 
     static const char kRDFNameSpaceURI[] = RDF_NAMESPACE_URI;
-    char buf[sizeof(kRDFNameSpaceURI) + 16];
-    nsFixedCString nextValStr(buf, sizeof(buf), 0);
+    nsAutoCStringN<sizeof(kRDFNameSpaceURI) + 16> nextValStr;
     nextValStr = kRDFNameSpaceURI;
     nextValStr.Append('_');
     nextValStr.AppendInt(nextVal, 10);

xpcom/string/nsPrintfCString.h

@@ -20,23 +20,18 @@
  *
  * See also nsCString::AppendPrintf().
  */
-class nsPrintfCString : public nsFixedCString
+class nsPrintfCString : public nsAutoCStringN<16>
 {
   typedef nsCString string_type;
 
 public:
   explicit nsPrintfCString(const char_type* aFormat, ...) MOZ_FORMAT_PRINTF(2, 3)
-    : nsFixedCString(mLocalBuffer, kLocalBufferSize, 0)
   {
     va_list ap;
     va_start(ap, aFormat);
     AppendPrintf(aFormat, ap);
     va_end(ap);
   }
-
-private:
-  static const uint32_t kLocalBufferSize = 16;
-  char_type mLocalBuffer[kLocalBufferSize];
 };
 
 #endif // !defined(nsPrintfCString_h___)