Bug 1341880 - do not emit trailing \0 in PrintfState; r=glandium

MozReview-Commit-ID: 2di7CsDCWLF

--HG--
extra : rebase_source : f5469d4b3e818204848123ea163c7f0f08563f7c

mozglue/misc/Printf.cpp

@@ -880,10 +880,6 @@ mozilla::PrintfTarget::vprint(const char* fmt, va_list ap)
         }
     }
 
-    // Stuff trailing NUL
-    if (!emit("\0", 1))
-        return false;
-
     return true;
 }
 

mozglue/misc/Printf.h

@@ -105,7 +105,7 @@ private:
 
 // Used in the implementation of Smprintf et al.
 template<typename AllocPolicy>
-class MOZ_STACK_CLASS SprintfState final : public mozilla::PrintfTarget, private AllocPolicy
+class MOZ_STACK_CLASS SprintfState final : private mozilla::PrintfTarget, private AllocPolicy
 {
  public:
     explicit SprintfState(char* base)
@@ -119,6 +119,12 @@ class MOZ_STACK_CLASS SprintfState final : public mozilla::PrintfTarget, private
         this->free_(mBase);
     }
 
+    bool vprint(const char* format, va_list ap_list) {
+        // The "" here has a single \0 character, which is what we're
+        // trying to append.
+        return mozilla::PrintfTarget::vprint(format, ap_list) && append("", 1);
+    }
+
     char* release() {
         char* result = mBase;
         mBase = nullptr;

xpcom/base/nsDebugImpl.cpp

@@ -265,7 +265,7 @@ GetAssertBehavior()
   return gAssertBehavior;
 }
 
-struct FixedBuffer : public mozilla::PrintfTarget
+struct FixedBuffer final : public mozilla::PrintfTarget
 {
   FixedBuffer() : curlen(0)
   {
@@ -285,11 +285,6 @@ FixedBuffer::append(const char* aBuf, size_t aLen)
     return true;
   }
 
-  // strip the trailing null, we add it again later
-  if (aBuf[aLen - 1] == '\0') {
-    --aLen;
-  }
-
   if (curlen + aLen >= sizeof(buffer)) {
     aLen = sizeof(buffer) - curlen - 1;
   }

xpcom/string/nsTSubstring.cpp

@@ -931,11 +931,6 @@ struct MOZ_STACK_CLASS PrintfAppend_CharT : public mozilla::PrintfTarget
       return true;
     }
 
-    // Printf sends us the final null terminator even though we don't want it
-    if (aStr[aLen - 1] == '\0') {
-      --aLen;
-    }
-
     mString->AppendASCII(aStr, aLen);
     return true;
   }