Add an OriginFilterBuilder class for [white|black]listing origins.

chrome/browser/browsing_data/origin_filter_builder.cc

Index: chrome/browser/browsing_data/origin_filter_builder.cc
diff --git a/chrome/browser/browsing_data/origin_filter_builder.cc b/chrome/browser/browsing_data/origin_filter_builder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..900b018310032b7c25264d00343dea8c920a9868
--- /dev/null
+++ b/chrome/browser/browsing_data/origin_filter_builder.cc
@@ -0,0 +1,111 @@
+// Copyright 2016 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/browser/browsing_data/origin_filter_builder.h"
+
+#include <string>
+#include <vector>
+
+#include "base/bind.h"
+
+namespace {
+
+bool NoopFilter(const GURL& url) {
+  return true;
+}
+
+}  // namespace
+
+OriginFilterBuilder::OriginFilterBuilder(Mode mode)
+    : mode_(mode) {
+}
+
+OriginFilterBuilder::~OriginFilterBuilder() {
+}
+
+void OriginFilterBuilder::AddOrigin(const url::Origin& origin) {
+  // TODO(msramek): Optimize OriginFilterBuilder for larger filters if needed.
+  DCHECK_LE(origin_list_.size(), 10U) << "OriginFilterBuilder is only suitable "
+                                         "for creating small filters.";
+
+  // By limiting the filter to non-unique origins, we can guarantee that
+  // origin1 < origin2 && origin1 > origin2 <=> origin1.isSameOrigin(origin2).
+  // This means that std::set::find() will use the same semantics for
+  // origin comparison as Origin::IsSameOriginWith(). Furthermore, this
+  // means that two filters are equal iff they are equal element-wise.
+  DCHECK(!origin.unique()) << "Invalid origin passed into OriginFilter.";
+
+  // TODO(msramek): All urls with file scheme currently map to the same
+  // origin. This is currently not a problem, but if it becomes one,
+  // consider recognizing the URL path.
+
+  origin_list_.insert(origin);
+}
+
+void OriginFilterBuilder::SetMode(Mode mode) {
+  mode_ = mode;
+}
+
+base::Callback<bool(const GURL&)>
+    OriginFilterBuilder::BuildSameOriginFilter() const {
+  std::set<url::Origin>* origins = new std::set<url::Origin>(origin_list_);
+  return base::Bind(&OriginFilterBuilder::MatchesURL,
+                    base::Owned(origins), mode_);
+}
+
+base::Callback<bool(const GURL&)>
+    OriginFilterBuilder::BuildDomainFilter() const {
+  std::set<url::Origin>* origins = new std::set<url::Origin>(origin_list_);
+  return base::Bind(&OriginFilterBuilder::MatchesURLWithSubdomains,
+                    base::Owned(origins), mode_);
+}
+
+// static
+base::Callback<bool(const GURL&)> OriginFilterBuilder::BuildNoopFilter() {
+  return base::Bind(&NoopFilter);
+}
+
+// static
+bool OriginFilterBuilder::MatchesURL(
+    std::set<url::Origin>* origins, Mode mode, const GURL& url) {
+  return ((origins->find(url::Origin(url)) != origins->end()) ==
+          (mode == WHITELIST));
+}
+
+// static
+bool OriginFilterBuilder::MatchesURLWithSubdomains(
+    std::set<url::Origin>* origins, Mode mode, const GURL& url) {
+  if (origins->empty())
+    return mode == BLACKLIST;
+
+  // If there is no concept of subdomains, simply delegate to MatchesURL().
+  if (url.HostIsIPAddress())
+    return MatchesURL(origins, mode, url);
+
+  // TODO(msramek): We do not expect filters to be particularly large.
+  // If they are, replace std::set with a trie for faster searching.
+  int port = url.EffectiveIntPort();
+  base::StringPiece host_piece = url.host_piece();
+  for (size_t i = 0; i < host_piece.length(); ++i) {
+    if (i != 0 && host_piece[i - 1] != '.')
+      continue;
+
+    url::Origin origin_with_removed_subdomain =
+        url::Origin::UnsafelyCreateOriginWithoutNormalization(
+            url.scheme_piece(),
+            host_piece.substr(i),
+            port);
+
+    // If we recognize the origin, return true for whitelist and false
+    // for blacklist.
+    if (origins->find(url::Origin(origin_with_removed_subdomain))
+        != origins->end()) {
+      return mode == WHITELIST;
+    }
+  }
+
+  // We do not recognize the URL. Return false for whitelist mode and true
+  // for blacklist mode.
+  return mode == BLACKLIST;
+}