ART: Refactor hidden_api

Add hidden_api.cc, move handling of hidden fields there. Also
remove an unnecessary include that meant hidden_api was imported
into too many compilation units, and fix transitive includes.

Bug: 73896556
Test: mmma art
Test: m test-art-host
Change-Id: Ie47e11abcea68e326c410bab215ebbfbf049051b
diff --git a/runtime/hidden_api.cc b/runtime/hidden_api.cc
new file mode 100644
index 0000000..f0b36a0
--- /dev/null
+++ b/runtime/hidden_api.cc
@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "hidden_api.h"
+
+#include "base/dumpable.h"
+
+namespace art {
+namespace hiddenapi {
+
+static inline std::ostream& operator<<(std::ostream& os, AccessMethod value) {
+  switch (value) {
+    case kReflection:
+      os << "reflection";
+      break;
+    case kJNI:
+      os << "JNI";
+      break;
+    case kLinking:
+      os << "linking";
+      break;
+  }
+  return os;
+}
+
+static constexpr bool EnumsEqual(EnforcementPolicy policy, HiddenApiAccessFlags::ApiList apiList) {
+  return static_cast<int>(policy) == static_cast<int>(apiList);
+}
+
+// GetMemberAction-related static_asserts.
+static_assert(
+    EnumsEqual(EnforcementPolicy::kAllLists, HiddenApiAccessFlags::kLightGreylist) &&
+    EnumsEqual(EnforcementPolicy::kDarkGreyAndBlackList, HiddenApiAccessFlags::kDarkGreylist) &&
+    EnumsEqual(EnforcementPolicy::kBlacklistOnly, HiddenApiAccessFlags::kBlacklist),
+    "Mismatch between EnforcementPolicy and ApiList enums");
+static_assert(
+    EnforcementPolicy::kAllLists < EnforcementPolicy::kDarkGreyAndBlackList &&
+    EnforcementPolicy::kDarkGreyAndBlackList < EnforcementPolicy::kBlacklistOnly,
+    "EnforcementPolicy values ordering not correct");
+
+namespace detail {
+
+MemberSignature::MemberSignature(ArtField* field) {
+  member_type_ = "field";
+  signature_parts_ = {
+    field->GetDeclaringClass()->GetDescriptor(&tmp_),
+    "->",
+    field->GetName(),
+    ":",
+    field->GetTypeDescriptor()
+  };
+}
+
+MemberSignature::MemberSignature(ArtMethod* method) {
+  member_type_ = "method";
+  signature_parts_ = {
+    method->GetDeclaringClass()->GetDescriptor(&tmp_),
+    "->",
+    method->GetName(),
+    method->GetSignature().ToString()
+  };
+}
+
+bool MemberSignature::DoesPrefixMatch(const std::string& prefix) const {
+  size_t pos = 0;
+  for (const std::string& part : signature_parts_) {
+    size_t count = std::min(prefix.length() - pos, part.length());
+    if (prefix.compare(pos, count, part, 0, count) == 0) {
+      pos += count;
+    } else {
+      return false;
+    }
+  }
+  // We have a complete match if all parts match (we exit the loop without
+  // returning) AND we've matched the whole prefix.
+  return pos == prefix.length();
+}
+
+bool MemberSignature::IsExempted(const std::vector<std::string>& exemptions) {
+  for (const std::string& exemption : exemptions) {
+    if (DoesPrefixMatch(exemption)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void MemberSignature::Dump(std::ostream& os) const {
+  for (std::string part : signature_parts_) {
+    os << part;
+  }
+}
+
+void MemberSignature::WarnAboutAccess(AccessMethod access_method,
+                                      HiddenApiAccessFlags::ApiList list) {
+  LOG(WARNING) << "Accessing hidden " << member_type_ << " " << Dumpable<MemberSignature>(*this)
+               << " (" << list << ", " << access_method << ")";
+}
+
+template<typename T>
+bool ShouldBlockAccessToMemberImpl(T* member, Action action, AccessMethod access_method) {
+  // Get the signature, we need it later.
+  MemberSignature member_signature(member);
+
+  Runtime* runtime = Runtime::Current();
+
+  if (action == kDeny) {
+    // If we were about to deny, check for an exemption first.
+    // Exempted APIs are treated as light grey list.
+    if (member_signature.IsExempted(runtime->GetHiddenApiExemptions())) {
+      action = kAllowButWarn;
+      // Avoid re-examining the exemption list next time.
+      // Note this results in the warning below showing "light greylist", which
+      // seems like what one would expect. Exemptions effectively add new members to
+      // the light greylist.
+      member->SetAccessFlags(HiddenApiAccessFlags::EncodeForRuntime(
+              member->GetAccessFlags(), HiddenApiAccessFlags::kLightGreylist));
+    }
+  }
+
+  // Print a log message with information about this class member access.
+  // We do this regardless of whether we block the access or not.
+  member_signature.WarnAboutAccess(access_method,
+      HiddenApiAccessFlags::DecodeFromRuntime(member->GetAccessFlags()));
+
+  if (action == kDeny) {
+    // Block access
+    return true;
+  }
+
+  // Allow access to this member but print a warning.
+  DCHECK(action == kAllowButWarn || action == kAllowButWarnAndToast);
+
+  // Depending on a runtime flag, we might move the member into whitelist and
+  // skip the warning the next time the member is accessed.
+  if (runtime->ShouldDedupeHiddenApiWarnings()) {
+    member->SetAccessFlags(HiddenApiAccessFlags::EncodeForRuntime(
+        member->GetAccessFlags(), HiddenApiAccessFlags::kWhitelist));
+  }
+
+  // If this action requires a UI warning, set the appropriate flag.
+  if (action == kAllowButWarnAndToast || runtime->ShouldAlwaysSetHiddenApiWarningFlag()) {
+    runtime->SetPendingHiddenApiWarning(true);
+  }
+
+  return false;
+}
+
+// Need to instantiate this.
+template bool ShouldBlockAccessToMemberImpl<ArtField>(ArtField* member,
+                                                      Action action,
+                                                      AccessMethod access_method);
+template bool ShouldBlockAccessToMemberImpl<ArtMethod>(ArtMethod* member,
+                                                       Action action,
+                                                       AccessMethod access_method);
+
+}  // namespace detail
+}  // namespace hiddenapi
+}  // namespace art