1 files changed, 151 insertions, 0 deletions
diff --git a/image/ImageURL.h b/image/ImageURL.h
new file mode 100644
index 000000000..fa60ff79e
--- /dev/null
+++ b/image/ImageURL.h
@@ -0,0 +1,151 @@
+/* -*- 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_image_ImageURL_h
+#define mozilla_image_ImageURL_h
+
+#include "nsIURI.h"
+#include "MainThreadUtils.h"
+#include "nsNetUtil.h"
+#include "mozilla/HashFunctions.h"
+#include "nsHashKeys.h"
+
+namespace mozilla {
+namespace image {
+
+class ImageCacheKey;
+
+/** ImageURL
+ *
+ * nsStandardURL is not threadsafe, so this class is created to hold only the
+ * necessary URL data required for image loading and decoding.
+ *
+ * Note: Although several APIs have the same or similar prototypes as those
+ * found in nsIURI/nsStandardURL, the class does not implement nsIURI. This is
+ * intentional; functionality is limited, and is only useful for imagelib code.
+ * By not implementing nsIURI, external code cannot unintentionally be given an
+ * nsIURI pointer with this limited class behind it; instead, conversion to a
+ * fully implemented nsIURI is required (e.g. through NS_NewURI).
+ */
+class ImageURL
+{
+public:
+  explicit ImageURL(nsIURI* aURI, nsresult& aRv)
+  {
+    MOZ_ASSERT(NS_IsMainThread(), "Cannot use nsIURI off main thread!");
+
+    aRv = aURI->GetSpec(mSpec);
+    NS_ENSURE_SUCCESS_VOID(aRv);
+
+    aRv = aURI->GetScheme(mScheme);
+    NS_ENSURE_SUCCESS_VOID(aRv);
+
+    aRv = aURI->GetRef(mRef);
+    NS_ENSURE_SUCCESS_VOID(aRv);
+  }
+
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ImageURL)
+
+  nsresult GetSpec(nsACString& result)
+  {
+    result = mSpec;
+    return NS_OK;
+  }
+
+  /// A weak pointer to the URI spec for this ImageURL. For logging only.
+  const char* Spec() const { return mSpec.get(); }
+
+  enum TruncatedSpecStatus {
+    FitsInto1k,
+    TruncatedTo1k
+  };
+  TruncatedSpecStatus GetSpecTruncatedTo1k(nsACString& result)
+  {
+    static const size_t sMaxTruncatedLength = 1024;
+
+    if (sMaxTruncatedLength >= mSpec.Length()) {
+      result = mSpec;
+      return FitsInto1k;
+    }
+
+    result = Substring(mSpec, 0, sMaxTruncatedLength);
+    return TruncatedTo1k;
+  }
+
+  nsresult GetScheme(nsACString& result)
+  {
+    result = mScheme;
+    return NS_OK;
+  }
+
+  nsresult SchemeIs(const char* scheme, bool* result)
+  {
+    NS_PRECONDITION(scheme, "scheme is null");
+    NS_PRECONDITION(result, "result is null");
+
+    *result = mScheme.Equals(scheme);
+    return NS_OK;
+  }
+
+  nsresult GetRef(nsACString& result)
+  {
+    result = mRef;
+    return NS_OK;
+  }
+
+  already_AddRefed<nsIURI> ToIURI()
+  {
+    MOZ_ASSERT(NS_IsMainThread(),
+               "Convert to nsIURI on main thread only; it is not threadsafe.");
+    nsCOMPtr<nsIURI> newURI;
+    NS_NewURI(getter_AddRefs(newURI), mSpec);
+    return newURI.forget();
+  }
+
+  bool operator==(const ImageURL& aOther) const
+  {
+    // Note that we don't need to consider mScheme and mRef, because they're
+    // already represented in mSpec.
+    return mSpec == aOther.mSpec;
+  }
+
+  bool HasSameRef(const ImageURL& aOther) const
+  {
+    return mRef == aOther.mRef;
+  }
+
+private:
+  friend class ImageCacheKey;
+
+  uint32_t ComputeHash(const Maybe<uint64_t>& aBlobSerial) const
+  {
+    if (aBlobSerial) {
+      // For blob URIs, we hash the serial number of the underlying blob, so that
+      // different blob URIs which point to the same blob share a cache entry. We
+      // also include the ref portion of the URI to support media fragments which
+      // requires us to create different Image objects even if the source data is
+      // the same.
+      return HashGeneric(*aBlobSerial, HashString(mRef));
+    }
+    // For non-blob URIs, we hash the URI spec.
+    return HashString(mSpec);
+  }
+
+  // Since this is a basic storage class, no duplication of spec parsing is
+  // included in the functionality. Instead, the class depends upon the
+  // parsing implementation in the nsIURI class used in object construction.
+  // This means each field is stored separately, but since only a few are
+  // required, this small memory tradeoff for threadsafe usage should be ok.
+  nsAutoCString mSpec;
+  nsAutoCString mScheme;
+  nsAutoCString mRef;
+
+  ~ImageURL() { }
+};
+
+} // namespace image
+} // namespace mozilla
+
+#endif // mozilla_image_ImageURL_h