Add DMGIterator, which composes the UDIFParser and HFSIterator.

No new tests at this level, since the components are both tested.

BUG=496898

Review URL: https://codereview.chromium.org/1292753008

Cr-Commit-Position: refs/heads/master@{#344447}

2 files changed, 142 insertions, 0 deletions

diff --git a/chrome/utility/safe_browsing/mac/dmg_iterator.cc b/chrome/utility/safe_browsing/mac/dmg_iterator.cc
new file mode 100644
index 0000000..270bef7
--- /dev/null
+++ b/chrome/utility/safe_browsing/mac/dmg_iterator.cc
@@ -0,0 +1,83 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/utility/safe_browsing/mac/dmg_iterator.h"
+
+#include "chrome/utility/safe_browsing/mac/hfs.h"
+#include "chrome/utility/safe_browsing/mac/read_stream.h"
+
+namespace safe_browsing {
+namespace dmg {
+
+DMGIterator::DMGIterator(ReadStream* stream)
+    : udif_(stream),
+      partitions_(),
+      current_partition_(0),
+      hfs_() {
+}
+
+DMGIterator::~DMGIterator() {}
+
+bool DMGIterator::Open() {
+  if (!udif_.Parse())
+    return false;
+
+  // Collect all the HFS partitions up-front. The data are accessed lazily, so
+  // this is relatively inexpensive.
+  for (size_t i = 0; i < udif_.GetNumberOfPartitions(); ++i) {
+    if (udif_.GetPartitionType(i) == "Apple_HFS" ||
+        udif_.GetPartitionType(i) == "Apple_HFSX") {
+      partitions_.push_back(udif_.GetPartitionReadStream(i).Pass());
+    }
+  }
+
+  return partitions_.size() > 0;
+}
+
+bool DMGIterator::Next() {
+  // Iterate through all the HFS partitions in the DMG file.
+  for (; current_partition_ < partitions_.size(); ++current_partition_) {
+    if (!hfs_) {
+      hfs_.reset(new HFSIterator(partitions_[current_partition_]));
+      if (!hfs_->Open())
+        continue;
+    }
+
+    // Iterate through the HFS filesystem until a concrete file is found.
+    while (true) {
+      if (!hfs_->Next())
+        break;
+
+      // Skip directories and symlinks.
+      if (hfs_->IsDirectory() || hfs_->IsSymbolicLink())
+        continue;
+
+      // Hard links are not supported by the HFSIterator.
+      if (hfs_->IsHardLink())
+        continue;
+
+      // Decmpfs compression is not supported by the HFSIterator.
+      if (hfs_->IsDecmpfsCompressed())
+        continue;
+
+      // This must be a normal file!
+      return true;
+    }
+
+    hfs_.reset();
+  }
+
+  return false;
+}
+
+base::string16 DMGIterator::GetPath() {
+  return hfs_->GetPath();
+}
+
+scoped_ptr<ReadStream> DMGIterator::GetReadStream() {
+  return hfs_->GetReadStream();
+}
+
+}  // namespace dmg
+}  // namespace safe_browsing
diff --git a/chrome/utility/safe_browsing/mac/dmg_iterator.h b/chrome/utility/safe_browsing/mac/dmg_iterator.h
new file mode 100644
index 0000000..763285c
--- /dev/null
+++ b/chrome/utility/safe_browsing/mac/dmg_iterator.h
@@ -0,0 +1,59 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_UTILITY_SAFE_BROWSING_MAC_DMG_ITERATOR_H_
+#define CHROME_UTILITY_SAFE_BROWSING_MAC_DMG_ITERATOR_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "base/strings/string16.h"
+#include "chrome/utility/safe_browsing/mac/udif.h"
+
+namespace safe_browsing {
+namespace dmg {
+
+class HFSIterator;
+class ReadStream;
+
+// DMGIterator provides iterator access over all of the concrete files located
+// on HFS+ and HFSX volumes in a UDIF/DMG file. This class maintains the
+// limitations of its composed components.
+class DMGIterator {
+ public:
+  // Creates a DMGIterator from a ReadStream. In most cases, this will be a
+  // FileReadStream opened from a DMG file. This does not take ownership
+  // of the stream.
+  explicit DMGIterator(ReadStream* stream);
+  ~DMGIterator();
+
+  // Opens the DMG file for iteration. This must be called before any other
+  // method. If this returns false, it is illegal to call any other methods
+  // on this class. If this returns true, the iterator is advanced to an
+  // invalid element before the first item.
+  bool Open();
+
+  // Advances the iterator to the next file item. Returns true on success
+  // and false on end-of-iterator.
+  bool Next();
+
+  // Returns the full path in a DMG filesystem to the current file item.
+  base::string16 GetPath();
+
+  // Returns a ReadStream for the current file item.
+  scoped_ptr<ReadStream> GetReadStream();
+
+ private:
+  UDIFParser udif_;  // The UDIF parser that accesses the partitions.
+  ScopedVector<ReadStream> partitions_;  // Streams for all the HFS partitions.
+  size_t current_partition_;  // The index in |partitions_| of the current one.
+  scoped_ptr<HFSIterator> hfs_;  // The HFSIterator for |current_partition_|.
+
+  DISALLOW_COPY_AND_ASSIGN(DMGIterator);
+};
+
+}  // namespace dmg
+}  // namespace safe_browsing
+
+#endif  // CHROME_UTILITY_SAFE_BROWSING_MAC_DMG_ITERATOR_H_