The Tor Browser: dom/bindings/DOMString.h@6474c204b198 (annotated)

dom/bindings/DOMString.h@6474c204b198 (annotated)

dom/bindings/DOMString.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef mozilla_dom_DOMString_h
 #define mozilla_dom_DOMString_h
 #include "nsStringGlue.h"
 #include "nsStringBuffer.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/Maybe.h"
 #include "nsDOMString.h"
 #include "nsIAtom.h"
 namespace mozilla {
 namespace dom {
 /**
  * A class for representing string return values.  This can be either passed to
  * callees that have an nsString or nsAString out param or passed to a callee
  * that actually knows about this class and can work with it.  Such a callee may
  * call SetStringBuffer or SetOwnedString or SetOwnedAtom on this object, but
  * only if it plans to keep holding a strong ref to the internal stringbuffer!
  *
  * The proper way to store a value in this class is to either to do nothing
  * (which leaves this as an empty string), to call SetStringBuffer with a
  * non-null stringbuffer, to call SetOwnedString, to call SetOwnedAtom, to call
  * SetNull(), or to call AsAString() and set the value in the resulting
  * nsString.  These options are mutually exclusive! Don't do more than one of
  * them.
  *
  * The proper way to extract a value is to check IsNull().  If not null, then
  * check HasStringBuffer().  If that's true, check for a zero length, and if the
  * length is nonzero call StringBuffer().  If the length is zero this is the
  * empty string.  If HasStringBuffer() returns false, call AsAString() and get
  * the value from that.
  */
 class MOZ_STACK_CLASS DOMString {
 public:
   DOMString()
     : mStringBuffer(nullptr)
     , mLength(0)
     , mIsNull(false)
   {}
   ~DOMString()
   {
     MOZ_ASSERT(mString.empty() || !mStringBuffer,
                "Shouldn't have both present!");
   }
   operator nsString&()
   {
     return AsAString();
   }
   nsString& AsAString()
   {
     MOZ_ASSERT(!mStringBuffer, "We already have a stringbuffer?");
     MOZ_ASSERT(!mIsNull, "We're already set as null");
     if (mString.empty()) {
       mString.construct();
     }
     return mString.ref();
   }
   bool HasStringBuffer() const
   {
     MOZ_ASSERT(mString.empty() || !mStringBuffer,
                "Shouldn't have both present!");
     MOZ_ASSERT(!mIsNull, "Caller should have checked IsNull() first");
     return mString.empty();
   }
   // Get the stringbuffer.  This can only be called if HasStringBuffer()
   // returned true and StringBufferLength() is nonzero.  If that's true, it will
   // never return null.
   nsStringBuffer* StringBuffer() const
   {
     MOZ_ASSERT(!mIsNull, "Caller should have checked IsNull() first");
     MOZ_ASSERT(HasStringBuffer(),
                "Don't ask for the stringbuffer if we don't have it");
     MOZ_ASSERT(StringBufferLength() != 0, "Why are you asking for this?");
     MOZ_ASSERT(mStringBuffer,
                "If our length is nonzero, we better have a stringbuffer.");
     return mStringBuffer;
   }
   // Get the length of the stringbuffer.  Can only be called if
   // HasStringBuffer().
   uint32_t StringBufferLength() const
   {
     MOZ_ASSERT(HasStringBuffer(), "Don't call this if there is no stringbuffer");
     return mLength;
   }
   void SetStringBuffer(nsStringBuffer* aStringBuffer, uint32_t aLength)
   {
     MOZ_ASSERT(mString.empty(), "We already have a string?");
     MOZ_ASSERT(!mIsNull, "We're already set as null");
     MOZ_ASSERT(!mStringBuffer, "Setting stringbuffer twice?");
     MOZ_ASSERT(aStringBuffer, "Why are we getting null?");
     mStringBuffer = aStringBuffer;
     mLength = aLength;
   }
   void SetOwnedString(const nsAString& aString)
   {
     MOZ_ASSERT(mString.empty(), "We already have a string?");
     MOZ_ASSERT(!mIsNull, "We're already set as null");
     MOZ_ASSERT(!mStringBuffer, "Setting stringbuffer twice?");
     nsStringBuffer* buf = nsStringBuffer::FromString(aString);
     if (buf) {
       SetStringBuffer(buf, aString.Length());
     } else if (aString.IsVoid()) {
       SetNull();
     } else if (!aString.IsEmpty()) {
       AsAString() = aString;
     }
   }
   enum NullHandling
   {
     eTreatNullAsNull,
     eTreatNullAsEmpty,
     eNullNotExpected
   };
   void SetOwnedAtom(nsIAtom* aAtom, NullHandling aNullHandling)
   {
     MOZ_ASSERT(mString.empty(), "We already have a string?");
     MOZ_ASSERT(!mIsNull, "We're already set as null");
     MOZ_ASSERT(!mStringBuffer, "Setting stringbuffer twice?");
     MOZ_ASSERT(aAtom || aNullHandling != eNullNotExpected);
     if (aNullHandling == eNullNotExpected || aAtom) {
       SetStringBuffer(aAtom->GetStringBuffer(), aAtom->GetLength());
     } else if (aNullHandling == eTreatNullAsNull) {
       SetNull();
     }
   }
   void SetNull()
   {
     MOZ_ASSERT(!mStringBuffer, "Should have no stringbuffer if null");
     MOZ_ASSERT(mString.empty(), "Should have no string if null");
     mIsNull = true;
   }
   bool IsNull() const
   {
     MOZ_ASSERT(!mStringBuffer || mString.empty(),
                "How could we have a stringbuffer and a nonempty string?");
     return mIsNull || (!mString.empty() && mString.ref().IsVoid());
   }
   void ToString(nsAString& aString)
   {
     if (IsNull()) {
       SetDOMStringToNull(aString);
     } else if (HasStringBuffer()) {
       if (StringBufferLength() == 0) {
         aString.Truncate();
       } else {
         StringBuffer()->ToString(StringBufferLength(), aString);
       }
     } else {
       aString = AsAString();
     }
   }
 private:
   // We need to be able to act like a string as needed
   Maybe<nsAutoString> mString;
   // For callees that know we exist, we can be a stringbuffer/length/null-flag
   // triple.
   nsStringBuffer* mStringBuffer;
   uint32_t mLength;
   bool mIsNull;
 };
 } // namespace dom
 } // namespace mozilla
 #endif // mozilla_dom_DOMString_h

The Tor Browser / annotate

dom/bindings/DOMString.h@6474c204b198 (annotated)

dom/bindings/DOMString.h