Support replacement of IP address resolutions via command line flag

net/base/ip_pattern.h

Index: net/base/ip_pattern.h
diff --git a/net/base/ip_pattern.h b/net/base/ip_pattern.h
new file mode 100644
index 0000000000000000000000000000000000000000..90a72c8f22628baa2280cf2944aa92b5aaf55e69
--- /dev/null
+++ b/net/base/ip_pattern.h
@@ -0,0 +1,65 @@
+// Copyright (c) 2014 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 NET_BASE_IP_PATTERN_H_
+#define NET_BASE_IP_PATTERN_H_
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/strings/string_piece.h"
+#include "net/base/address_list.h"

[wtc, 2014/02/11 23:52:30]

Include "net/base/net_util.h" instead. You just need the definition of
IPAddressNumber.

[jar (doing other things), 2014/02/15 21:14:56]

Done.

+#include "net/base/net_export.h"
+
+namespace net {
+
+// IPPatterns are used to match IP address resolutions for possible augmentation
+// by a MappedIPResolver, which uses IPMappingRules.
+class NET_EXPORT IPPattern {
+ public:
+  IPPattern();
+  ~IPPattern();
+
+  bool ParsePattern(const std::string& ip_pattern);
+  bool Match(const IPAddressNumber& address) const;

[wtc, 2014/02/11 23:52:30]

Nit: document these two methods.

[jar (doing other things), 2014/02/15 21:14:56]

Done.

+
+  bool is_ipv4() const { return is_ipv4_; }
+
+ private:
+  class ComponentPattern;
+  typedef std::vector<std::string> Strings;
+  // IPv6 addresses have 8 components, while IPv4 addresses have 4 components.
+  // ComponentPattern is used to define patterns to match individual components.
+  bool ParseComponentPattern(const std::string& text,
+                             ComponentPattern* pattern) const;
+  // Convert IP component to an int.  Assume hex vs decimal for IPV6 vs V4.
+  bool ValueTextToInt(const base::StringPiece& input, uint32* output) const;

[wtc, 2014/02/11 23:52:30]

All uses of uint32 in this class probably should be changed to uint16. Four
hexadecimal digits represent two bytes, or uint16. It is possible that using
uint32 is more convenient though.

[jar (doing other things), 2014/02/15 21:14:56]

It was a mistake... but uint32 is more convenient for both conversion and bounds
checking.

+
+  bool is_ipv4_;
+  // The |ip_mask_| indicates,for each component, if this pattern requires an

[wtc, 2014/02/11 23:52:30]

Nit: add a space before "for".

[jar (doing other things), 2014/02/15 21:14:56]

Done.

+  // exact match (OCTET in IPv4, or 4 hex digits in IPv6).
+  // For each true element there is an entry in |component_values_|, and false
+  // means that an entry from our list of ComponentPattern instances must be
+  // applied.
+  std::vector<bool> ip_mask_;
+  // The vector of fixed values that are requried.
+  // Other values may be restricted by the component_patterns_;
+  // The class invariant is:
+  // ip_mask_.size() == component_patterns_.size()
+  //                    + size(our ComponentPattern list)
+  std::vector<uint32> component_values_;
+  // The head of our linked list of ComponentPatterns.
+  // If only one component position was specified using a range, then this
+  // list will only have 1 element (i.e., we only have patterns for each element
+  // of ip_mask_ that is false.)
+  // We own these elements, and need to destroy them all when we are destroyed.
+  ComponentPattern* first_component_pattern_;

[Ryan Hamilton, 2014/02/12 00:44:03]

Ditto here.  Instead of implementing the list traversal and element deletion
manually in the destructor, using a list<ComponentPattern> would let you simply
say:

STLDeleteElements(&component_patterns_) in the destructor.

I think this would improve readability.

[jar (doing other things), 2014/02/15 21:14:56]

Done.

+  DISALLOW_COPY_AND_ASSIGN(IPPattern);

[wtc, 2014/02/11 23:52:30]

Nit: I suggest adding a blank line to separate these members.

[jar (doing other things), 2014/02/15 21:14:56]

Done.

+};
+
+

[wtc, 2014/02/11 23:52:30]

Nit: delete one blank line.

[jar (doing other things), 2014/02/15 21:14:56]

Done.

+}  // namespace net
+
+#endif  // NET_BASE_IP_PATTERN_H_