image/src/ImageURL.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef MOZILLA_IMAGELIB_IMAGEURL_H_
   7 #define MOZILLA_IMAGELIB_IMAGEURL_H_
   8
   9 #include "nsIURI.h"
  10 #include "MainThreadUtils.h"
  11 #include "nsNetUtil.h"
  12
  13 namespace mozilla {
  14 namespace image {
  15
  16 /** ImageURL
  17  *
  18  * nsStandardURL is not threadsafe, so this class is created to hold only the
  19  * necessary URL data required for image loading and decoding.
  20  *
  21  * Note: Although several APIs have the same or similar prototypes as those
  22  * found in nsIURI/nsStandardURL, the class does not implement nsIURI. This is
  23  * intentional; functionality is limited, and is only useful for imagelib code.
  24  * By not implementing nsIURI, external code cannot unintentionally be given an
  25  * nsIURI pointer with this limited class behind it; instead, conversion to a
  26  * fully implemented nsIURI is required (e.g. through NS_NewURI).
  27  */
  28 class ImageURL
  29 {
  30 public:
  31   explicit ImageURL(nsIURI* aURI)
  32   {
  33     MOZ_ASSERT(NS_IsMainThread(), "Cannot use nsIURI off main thread!");
  34     aURI->GetSpec(mSpec);
  35     aURI->GetScheme(mScheme);
  36     aURI->GetRef(mRef);
  37   }
  38
  39   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ImageURL)
  40
  41   nsresult GetSpec(nsACString& result)
  42   {
  43     result = mSpec;
  44     return NS_OK;
  45   }
  46
  47   nsresult GetScheme(nsACString& result)
  48   {
  49     result = mScheme;
  50     return NS_OK;
  51   }
  52
  53   nsresult SchemeIs(const char* scheme, bool* result)
  54   {
  55     NS_PRECONDITION(scheme, "scheme is null");
  56     NS_PRECONDITION(result, "result is null");
  57
  58     *result = mScheme.Equals(scheme);
  59     return NS_OK;
  60   }
  61
  62   nsresult GetRef(nsACString& result)
  63   {
  64     result = mRef;
  65     return NS_OK;
  66   }
  67
  68   already_AddRefed<nsIURI> ToIURI()
  69   {
  70     MOZ_ASSERT(NS_IsMainThread(),
  71                "Convert to nsIURI on main thread only; it is not threadsafe.");
  72     nsCOMPtr<nsIURI> newURI;
  73     NS_NewURI(getter_AddRefs(newURI), mSpec);
  74     return newURI.forget();
  75   }
  76
  77 private:
  78   // Since this is a basic storage class, no duplication of spec parsing is
  79   // included in the functionality. Instead, the class depends upon the
  80   // parsing implementation in the nsIURI class used in object construction.
  81   // This means each field is stored separately, but since only a few are
  82   // required, this small memory tradeoff for threadsafe usage should be ok.
  83   nsAutoCString mSpec;
  84   nsAutoCString mScheme;
  85   nsAutoCString mRef;
  86
  87   ~ImageURL() { }
  88 };
  89
  90 } // namespace image
  91 } // namespace mozilla
  92
  93 #endif // MOZILLA_IMAGELIB_IMAGEURL_H_