public void Prefetch_InitialPages()
{
const int NumBooks = 3;
var context = new PageCacheContext(ScreenWidth, GetLibrary(NumBooks));
// Run method
var policy = new PagePrefetchAndRetainPolicy()
{
Retain_Initial = 10
};
var keys = policy.PrefetchKeyOrder(context);
AssertMustRetainAllKeys(keys, policy, context);
// Check for each book
var booksPos = context.BookPositions;
for (int bookIdx = 0; bookIdx < NumBooks; bookIdx++)
{
// Has the GUID
CollectionAssert.Contains(keys.Select(x=>x.BookId), booksPos[bookIdx].BookId);
// Has all the elements
var bookKeys = LinqExtensions.IntRange(1, 10)
.Select(x => new PageKey(booksPos[bookIdx].BookId, x, ScreenWidth));
CollectionAssert.IsSubsetOf(bookKeys, keys);
}
}
public void EmptyPolicy()
{
var policy = new PagePrefetchAndRetainPolicy();
var key = new PageKey(Guid.Empty, 1, ScreenWidth);
var context = new PageCacheContext(ScreenWidth, GetLibrary(0));
Assert.IsFalse(policy.MustRetain(key, context), "not retain with empty library");
var dict = GetCacheDict(0);
CollectionAssert.IsEmpty(policy.KeysToRemove(dict, context), "no keys exist");
dict = GetCacheDict(5);
CollectionAssert.AreEquivalent(dict.Keys, policy.KeysToRemove(dict, context), "return all keys");
CollectionAssert.IsEmpty(policy.PrefetchKeyOrder(context), "prefetch list empty");
}
public void Prefetch_CurrentBookFirst()
{
const int NumBooks = 3;
var library = GetLibrary(NumBooks);
library.CurrentBook = library.Books.Last();
var context = new PageCacheContext(ScreenWidth, library);
// Run method
var policy = new PagePrefetchAndRetainPolicy()
{
Retain_Initial = 10
};
var keys = policy.PrefetchKeyOrder(context);
// Has all the elements
var curBookKeys = LinqExtensions.IntRange(1, 10)
.Select(x => new PageKey(library.CurrentBook.Id, x, ScreenWidth));
CollectionAssert.AreEqual(curBookKeys, keys.Take(10), "current book's pages come first");
}
public void Stop()
{
_stopLoop = true;
_currentContext = null;
_waitForContextChange.Set();
// Wait for the thread to end
_prefetchThread.Join();
}
void OnCacheContextChanged(object sender, EvArgs<PageCacheContext> e)
{
_currentContext = e.Value;
_waitForContextChange.Set();
}
public void Prefetch_CurrentPage()
{
var library = GetLibrary(1);
Book book = library.Books[0];
book.CurrentPosition = PositionInBook.FromPhysicalPage(33, 100);
var context = new PageCacheContext(ScreenWidth, library);
var policy = new PagePrefetchAndRetainPolicy();
var keys = policy.PrefetchKeyOrder(context);
AssertMustRetainAllKeys(keys, policy, context);
Assert.AreEqual(1, keys.Count());
Assert.AreEqual(33, keys.First().PageNum);
}
void AssertMustRetainAllKeys(IEnumerable<PageKey> keys, IPageRetainPolicy policy, PageCacheContext context)
{
foreach (var key in keys)
{
Assert.IsTrue(policy.MustRetain(key, context), "Must retain all prefetched keys");
}
}
public void Remove_KeepOtherItems()
{
var context = new PageCacheContext(ScreenWidth, GetLibrary(1));
var policy = new PagePrefetchAndRetainPolicy()
{
OtherItemsToKeepCount = 7
};
var dict = GetCacheDict(10);
var keysToRemove = policy.KeysToRemove(dict, context);
// Keeping 7 items, removing 3
Assert.AreEqual(3, keysToRemove.Count());
// Makes sure *oldest* ones are removed
Assert.AreEqual(BaseTime + TimeSpan.FromDays(0), dict[keysToRemove.ElementAt(2)].LastAccessTime);
Assert.AreEqual(BaseTime + TimeSpan.FromDays(1), dict[keysToRemove.ElementAt(1)].LastAccessTime);
Assert.AreEqual(BaseTime + TimeSpan.FromDays(2), dict[keysToRemove.ElementAt(0)].LastAccessTime);
// Must NOT retain those keys
foreach (var key in keysToRemove)
{
Assert.IsFalse(policy.MustRetain(key, context));
}
}
public void Remove_AllNotFetched()
{
var library = GetLibrary(3);
var context = new PageCacheContext(ScreenWidth, library);
var policy = new PagePrefetchAndRetainPolicy()
{
Retain_Initial = 2
};
var dict = GetCacheDict(10, library.Books.ToArray());
var keysToRemove = policy.KeysToRemove(dict, context);
CollectionAssert.AreEquivalent(
LinqExtensions.IntRange(3, 8).RepeatSequence(3),
keysToRemove.Select(x => x.PageNum));
}
public void Prefetch_ThreeBooksComplex()
{
var library = GetLibrary(3);
Book curBook = library.Books.Last();
library.CurrentBook = curBook;
curBook.CurrentPosition = PositionInBook.FromPhysicalPage(33, 100);
library.Books[1].CurrentPosition = PositionInBook.FromPhysicalPage(66, 100);
var context = new PageCacheContext(ScreenWidth, library);
var policy = new PagePrefetchAndRetainPolicy()
{
Retain_InCurrentBookAfter = 3,
Retain_InCurrentBookBefore = 1,
Retain_InOtherBookAfter = 2,
Retain_InOtherBookBefore = 1,
Retain_Initial = 2
};
var keys = policy.PrefetchKeyOrder(context);
AssertMustRetainAllKeys(keys, policy, context);
CollectionAssert.AreEqual(
LinqExtensions.RepeatElements(curBook.Id, 7),
keys.Take(7).Select(x => x.BookId), "First items from current book");
// Complex pattern, read the rules...
CollectionAssert.AreEqual(
new int[] {
33, 34, 35, 32, 36, 1, 2,
1, 2,
66, 67, 68, 65, 1, 2
},
keys.Select(x => x.PageNum));
}
public void Prefetch_CurrentPageComplex()
{
var library = GetLibrary(1);
Book book = library.Books[0];
library.CurrentBook = book;
book.CurrentPosition = PositionInBook.FromPhysicalPage(33, 100);
var context = new PageCacheContext(ScreenWidth, library);
var policy = new PagePrefetchAndRetainPolicy()
{
Retain_InCurrentBookBefore = 2,
Retain_InCurrentBookAfter = 7,
Retain_Initial = 3
};
var keys = policy.PrefetchKeyOrder(context);
AssertMustRetainAllKeys(keys, policy, context);
// current, 2 x after, 1 x before..., initial
CollectionAssert.AreEqual(
new int[] { 33, 34, 35, 32, 36, 37, 31, 38, 39, 40, 1, 2, 3 },
keys.Select(x => x.PageNum));
}
public void Prefetch_CurrentPageBefore()
{
var library = GetLibrary(1);
Book book = library.Books[0];
library.CurrentBook = book;
book.CurrentPosition = PositionInBook.FromPhysicalPage(33, 100);
var context = new PageCacheContext(ScreenWidth, library);
var policy = new PagePrefetchAndRetainPolicy()
{
Retain_InCurrentBookBefore = 10
};
var keys = policy.PrefetchKeyOrder(context);
AssertMustRetainAllKeys(keys, policy, context);
// Note that current page is added to the total, so 11 items, not 10
CollectionAssert.AreEqual(
LinqExtensions.IntRange(33-10, 11).Reverse(),
keys.Select(x => x.PageNum));
}