/// <summary>
/// Decompresses the items.
/// </summary>
private void DecompressItems()
{
ErrorUtilities.VerifyThrow(_uncompressedItems == null, "Items already decompressed.");
using (MemoryStream serializedStream = new MemoryStream(_compressedItems, 0, _compressedItems.Length, writable: false, publiclyVisible: true))
{
using (DeflateStream inflateStream = new DeflateStream(serializedStream, CompressionMode.Decompress))
{
INodePacketTranslator serializedBufferTranslator = NodePacketTranslator.GetReadTranslator(inflateStream, null);
LookasideStringInterner interner = new LookasideStringInterner(serializedBufferTranslator);
byte[] buffer = null;
serializedBufferTranslator.Translate(ref buffer);
ErrorUtilities.VerifyThrow(buffer != null, "Unexpected null items buffer during decompression.");
using (MemoryStream itemsStream = new MemoryStream(buffer, 0, buffer.Length, writable: false, publiclyVisible: true))
{
INodePacketTranslator itemTranslator = NodePacketTranslator.GetReadTranslator(itemsStream, null);
_uncompressedItems = new TaskItem[_itemsCount];
for (int i = 0; i < _uncompressedItems.Length; i++)
{
_uncompressedItems[i] = TaskItem.FactoryForDeserialization(itemTranslator, interner);
}
}
}
}
_compressedItems = null;
}
public void ReuseOfDeserializedInternerNotAllowed()
{
var interner = new LookasideStringInterner(StringComparer.OrdinalIgnoreCase, 1);
int strIndex = interner.Intern("abc123def456");
MemoryStream stream = new MemoryStream();
INodePacketTranslator writetranslator = NodePacketTranslator.GetWriteTranslator(stream);
interner.Translate(writetranslator);
INodePacketTranslator readtranslator = NodePacketTranslator.GetReadTranslator(stream, null);
var newInterner = new LookasideStringInterner(readtranslator);
bool gotException = false;
try
{
newInterner.Intern("foo");
}
catch (Exception)
{
gotException = true;
}
Assert.IsTrue(gotException);
}
public void ComparerIsObeyed()
{
var interner = new LookasideStringInterner(StringComparer.OrdinalIgnoreCase, 1);
int strIndex = interner.Intern("abc123def456");
Assert.AreEqual(interner.Intern("ABC123DEF456"), strIndex);
var interner2 = new LookasideStringInterner(StringComparer.Ordinal, 1);
int strIndex2 = interner2.Intern("abc123def456");
Assert.AreNotEqual(interner.Intern("ABC123DEF456"), strIndex2);
}
public void BasicInterning()
{
var interner = new LookasideStringInterner(StringComparer.OrdinalIgnoreCase, 1);
int nullIndex = interner.Intern(null);
int emptyIndex = interner.Intern(String.Empty);
int strIndex = interner.Intern("abc123def456");
Assert.AreEqual(interner.Intern(null), nullIndex);
Assert.AreEqual(interner.Intern(String.Empty), emptyIndex);
Assert.AreEqual(interner.Intern("abc123def456"), strIndex);
Assert.AreEqual(interner.GetString(nullIndex), null);
Assert.AreEqual(interner.GetString(emptyIndex), String.Empty);
Assert.AreEqual(interner.GetString(strIndex), "abc123def456");
}
/// <summary>
/// Compresses the items.
/// </summary>
private void CompressItems()
{
ErrorUtilities.VerifyThrow(_compressedItems == null, "Items already compressed.");
// We will just calculate a very rough starting buffer size for the memory stream based on the number of items and a
// rough guess for an average number of bytes needed to store them compressed. This doesn't have to be accurate, just
// big enough to avoid unnecessary buffer reallocations in most cases.
int defaultCompressedBufferCapacity = _uncompressedItems.Length * 64;
using (MemoryStream serializedStream = new MemoryStream(defaultCompressedBufferCapacity))
{
using (DeflateStream deflateStream = new DeflateStream(serializedStream, CompressionMode.Compress))
{
INodePacketTranslator serializedBufferTranslator = NodePacketTranslator.GetWriteTranslator(deflateStream);
// Again, a rough calculation of buffer size, this time for an uncompressed buffer. We assume compression
// will give us 2:1, as it's all text.
int defaultUncompressedBufferCapacity = defaultCompressedBufferCapacity * 2;
using (MemoryStream itemsStream = new MemoryStream(defaultUncompressedBufferCapacity))
{
INodePacketTranslator itemTranslator = NodePacketTranslator.GetWriteTranslator(itemsStream);
// When creating the interner, we use the number of items as the initial size of the collections since the
// number of strings will be of the order of the number of items in the collection. This assumes basically
// one unique string per item (frequently a path related to the item) with most of the rest of the metadata
// being the same (and thus interning.) This is a hueristic meant to get us in the ballpark to avoid
// too many reallocations when growing the collections.
LookasideStringInterner interner = new LookasideStringInterner(StringComparer.Ordinal, _uncompressedItems.Length);
for (int i = 0; i < _uncompressedItems.Length; i++)
{
_uncompressedItems[i].TranslateWithInterning(itemTranslator, interner);
}
interner.Translate(serializedBufferTranslator);
byte[] buffer = itemsStream.ToArray();
serializedBufferTranslator.Translate(ref buffer);
}
}
_compressedItems = serializedStream.ToArray();
}
_uncompressedItems = null;
}
public void Serialization()
{
var interner = new LookasideStringInterner(StringComparer.OrdinalIgnoreCase, 1);
int nullIndex = interner.Intern(null);
int emptyIndex = interner.Intern(String.Empty);
int strIndex = interner.Intern("abc123def456");
MemoryStream stream = new MemoryStream();
INodePacketTranslator writetranslator = NodePacketTranslator.GetWriteTranslator(stream);
interner.Translate(writetranslator);
INodePacketTranslator readtranslator = NodePacketTranslator.GetReadTranslator(stream, null);
var newInterner = new LookasideStringInterner(readtranslator);
Assert.AreEqual(newInterner.GetString(nullIndex), null);
Assert.AreEqual(newInterner.GetString(emptyIndex), String.Empty);
Assert.AreEqual(newInterner.GetString(strIndex), "abc123def456");
}
public void Empty()
{
var interner = new LookasideStringInterner(StringComparer.OrdinalIgnoreCase, 1);
interner.GetString(0);
}