1 files changed, 278 insertions, 0 deletions
diff --git a/toolkit/components/url-classifier/ChunkSet.cpp b/toolkit/components/url-classifier/ChunkSet.cpp
new file mode 100644
index 000000000..162a74260
--- /dev/null
+++ b/toolkit/components/url-classifier/ChunkSet.cpp
@@ -0,0 +1,278 @@
+//* -*- Mode: C++; tab-width: 8; 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/. */
+
+#include "ChunkSet.h"
+
+namespace mozilla {
+namespace safebrowsing {
+
+const size_t ChunkSet::IO_BUFFER_SIZE;
+
+nsresult
+ChunkSet::Serialize(nsACString& aChunkStr)
+{
+  aChunkStr.Truncate();
+  for (const Range* range = mRanges.begin(); range != mRanges.end(); range++) {
+    if (range != mRanges.begin()) {
+      aChunkStr.Append(',');
+    }
+
+    aChunkStr.AppendInt((int32_t)range->Begin());
+    if (range->Begin() != range->End()) {
+      aChunkStr.Append('-');
+      aChunkStr.AppendInt((int32_t)range->End());
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult
+ChunkSet::Set(uint32_t aChunk)
+{
+  if (!Has(aChunk)) {
+    Range chunkRange(aChunk, aChunk);
+
+    if (mRanges.Length() == 0) {
+      if (!mRanges.AppendElement(chunkRange, fallible)) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+      return NS_OK;
+    }
+
+    if (mRanges.LastElement().Precedes(chunkRange)) {
+      mRanges.LastElement().End(aChunk);
+    } else if (chunkRange.Precedes(mRanges[0])) {
+      mRanges[0].Begin(aChunk);
+    } else {
+      ChunkSet tmp;
+      if (!tmp.mRanges.AppendElement(chunkRange, fallible)) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+
+      return Merge(tmp);
+    }
+  }
+
+  return NS_OK;
+}
+
+bool
+ChunkSet::Has(uint32_t aChunk) const
+{
+  size_t idx;
+  return BinarySearchIf(mRanges, 0, mRanges.Length(),
+                        Range::IntersectionComparator(Range(aChunk, aChunk)),
+                        &idx);
+                        // IntersectionComparator works because we create a
+                        // single-chunk range.
+}
+
+nsresult
+ChunkSet::Merge(const ChunkSet& aOther)
+{
+  size_t oldLen = mRanges.Length();
+
+  for (const Range* mergeRange = aOther.mRanges.begin();
+       mergeRange != aOther.mRanges.end(); mergeRange++) {
+    if (!HasSubrange(*mergeRange)) {
+      if (!mRanges.InsertElementSorted(*mergeRange, fallible)) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+    }
+  }
+
+  if (oldLen < mRanges.Length()) {
+    for (size_t i = 1; i < mRanges.Length(); i++) {
+      while (mRanges[i - 1].FoldLeft(mRanges[i])) {
+        mRanges.RemoveElementAt(i);
+
+        if (i == mRanges.Length()) {
+          return NS_OK;
+        }
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+uint32_t
+ChunkSet::Length() const
+{
+  uint32_t len = 0;
+  for (const Range* range = mRanges.begin(); range != mRanges.end(); range++) {
+    len += range->Length();
+  }
+
+  return len;
+}
+
+nsresult
+ChunkSet::Remove(const ChunkSet& aOther)
+{
+  for (const Range* removalRange = aOther.mRanges.begin();
+       removalRange != aOther.mRanges.end(); removalRange++) {
+
+    if (mRanges.Length() == 0) {
+      return NS_OK;
+    }
+
+    if (mRanges.LastElement().End() < removalRange->Begin() ||
+        aOther.mRanges.LastElement().End() < mRanges[0].Begin()) {
+      return NS_OK;
+    }
+
+    size_t intersectionIdx;
+    while (BinarySearchIf(mRanges, 0, mRanges.Length(),
+           Range::IntersectionComparator(*removalRange), &intersectionIdx)) {
+
+      ChunkSet remains;
+      nsresult rv = mRanges[intersectionIdx].Remove(*removalRange, remains);
+
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      mRanges.RemoveElementAt(intersectionIdx);
+      if (!mRanges.InsertElementsAt(intersectionIdx, remains.mRanges,
+                                    fallible)) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+void
+ChunkSet::Clear()
+{
+  mRanges.Clear();
+}
+
+nsresult
+ChunkSet::Write(nsIOutputStream* aOut)
+{
+  nsTArray<uint32_t> chunks(IO_BUFFER_SIZE);
+
+  for (const Range* range = mRanges.begin(); range != mRanges.end(); range++) {
+    for (uint32_t chunk = range->Begin(); chunk <= range->End(); chunk++) {
+      chunks.AppendElement(chunk);
+
+      if (chunks.Length() == chunks.Capacity()) {
+        nsresult rv = WriteTArray(aOut, chunks);
+
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+
+        chunks.Clear();
+      }
+    }
+  }
+
+  nsresult rv = WriteTArray(aOut, chunks);
+
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+ChunkSet::Read(nsIInputStream* aIn, uint32_t aNumElements)
+{
+  nsTArray<uint32_t> chunks(IO_BUFFER_SIZE);
+
+  while (aNumElements != 0) {
+    chunks.Clear();
+
+    uint32_t numToRead = aNumElements > IO_BUFFER_SIZE ? IO_BUFFER_SIZE : aNumElements;
+
+    nsresult rv = ReadTArray(aIn, &chunks, numToRead);
+
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    aNumElements -= numToRead;
+
+    for (const uint32_t* c = chunks.begin(); c != chunks.end(); c++) {
+      rv = Set(*c);
+
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+bool
+ChunkSet::HasSubrange(const Range& aSubrange) const
+{
+  for (const Range* range = mRanges.begin(); range != mRanges.end(); range++) {
+    if (range->Contains(aSubrange)) {
+      return true;
+    } else if (!(aSubrange.Begin() > range->End() ||
+                 range->Begin() > aSubrange.End())) {
+      // In this case, aSubrange overlaps this range but is not a subrange.
+      // because the ChunkSet implementation ensures that there are no
+      // overlapping ranges, this means that aSubrange cannot be a subrange of
+      // any of the following ranges
+      return false;
+    }
+  }
+
+  return false;
+}
+
+uint32_t
+ChunkSet::Range::Length() const
+{
+  return mEnd - mBegin + 1;
+}
+
+nsresult
+ChunkSet::Range::Remove(const Range& aRange, ChunkSet& aRemainderSet) const
+{
+  if (mBegin < aRange.mBegin && aRange.mBegin <= mEnd) {
+    // aRange overlaps & follows this range
+    Range range(mBegin, aRange.mBegin - 1);
+    if (!aRemainderSet.mRanges.AppendElement(range, fallible)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+  }
+
+  if (mBegin <= aRange.mEnd && aRange.mEnd < mEnd) {
+    // aRange overlaps & precedes this range
+    Range range(aRange.mEnd + 1, mEnd);
+    if (!aRemainderSet.mRanges.AppendElement(range, fallible)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+  }
+
+  return NS_OK;
+}
+
+bool
+ChunkSet::Range::FoldLeft(const Range& aRange)
+{
+  if (Contains(aRange)) {
+    return true;
+  } else if (Precedes(aRange) ||
+             (mBegin <= aRange.mBegin && aRange.mBegin <= mEnd)) {
+    mEnd = aRange.mEnd;
+    return true;
+  }
+
+  return false;
+}
+
+} // namespace safebrowsing
+} // namespace mozilla