1 files changed, 149 insertions, 0 deletions
diff --git a/init/interface_utils.cpp b/init/interface_utils.cpp
new file mode 100644
index 000000000..a54860fa4
--- /dev/null
+++ b/init/interface_utils.cpp
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2019 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 "interface_utils.h"
+
+#include <fstream>
+#include <sstream>
+
+#include <android-base/strings.h>
+#include <hidl-util/FqInstance.h>
+#include <json/json.h>
+
+using android::FqInstance;
+using android::FQName;
+using android::base::Error;
+
+namespace android {
+namespace init {
+
+namespace {
+
+std::string FQNamesToString(const std::set<FQName>& fqnames) {
+    std::set<std::string> fqname_strings;
+    for (const FQName& fqname : fqnames) {
+        fqname_strings.insert(fqname.string());
+    }
+    return android::base::Join(fqname_strings, " ");
+}
+
+}  // namespace
+
+Result<InterfaceInheritanceHierarchyMap> ReadInterfaceInheritanceHierarchy(
+        const std::string& path) {
+    Json::Value root;
+    Json::Reader reader;
+    std::ifstream stream(path);
+    if (!reader.parse(stream, root)) {
+        return Error() << "Failed to read interface inheritance hierarchy file: " << path << "\n"
+                       << reader.getFormattedErrorMessages();
+    }
+
+    InterfaceInheritanceHierarchyMap result;
+    for (const Json::Value& entry : root) {
+        std::set<FQName> inherited_interfaces;
+        for (const Json::Value& intf : entry["inheritedInterfaces"]) {
+            FQName fqname;
+            if (!fqname.setTo(intf.asString())) {
+                return Error() << "Unable to parse interface '" << intf.asString() << "'";
+            }
+            inherited_interfaces.insert(fqname);
+        }
+        std::string intf_string = entry["interface"].asString();
+        FQName fqname;
+        if (!fqname.setTo(intf_string)) {
+            return Error() << "Unable to parse interface '" << intf_string << "'";
+        }
+        result[fqname] = inherited_interfaces;
+    }
+
+    return result;
+}
+
+Result<void> CheckInterfaceInheritanceHierarchy(const std::set<std::string>& instances,
+                                                const InterfaceInheritanceHierarchyMap& hierarchy) {
+    std::set<FQName> interface_fqnames;
+    for (const std::string& instance : instances) {
+        FqInstance fqinstance;
+        if (!fqinstance.setTo(instance)) {
+            return Error() << "Unable to parse interface instance '" << instance << "'";
+        }
+        interface_fqnames.insert(fqinstance.getFqName());
+    }
+    return CheckInterfaceInheritanceHierarchy(interface_fqnames, hierarchy);
+}
+
+Result<void> CheckInterfaceInheritanceHierarchy(const std::set<FQName>& interfaces,
+                                                const InterfaceInheritanceHierarchyMap& hierarchy) {
+    std::ostringstream error_stream;
+    for (const FQName& intf : interfaces) {
+        if (hierarchy.count(intf) == 0) {
+            error_stream << "\nInterface is not in the known set of hidl_interfaces: '"
+                         << intf.string()
+                         << "'. Please ensure the interface is spelled correctly and built "
+                         << "by a hidl_interface target.";
+            continue;
+        }
+        const std::set<FQName>& required_interfaces = hierarchy.at(intf);
+        std::set<FQName> diff;
+        std::set_difference(required_interfaces.begin(), required_interfaces.end(),
+                            interfaces.begin(), interfaces.end(),
+                            std::inserter(diff, diff.begin()));
+        if (!diff.empty()) {
+            error_stream << "\nInterface '" << intf.string() << "' requires its full inheritance "
+                         << "hierarchy to be listed in this init_rc file. Missing "
+                         << "interfaces: [" << FQNamesToString(diff) << "]";
+        }
+    }
+    const std::string& errors = error_stream.str();
+    if (!errors.empty()) {
+        return Error() << errors;
+    }
+
+    return {};
+}
+
+std::optional<std::set<FQName>> known_interfaces;
+
+void SetKnownInterfaces(const InterfaceInheritanceHierarchyMap& hierarchy) {
+    known_interfaces = std::set<FQName>();
+    for (const auto& [intf, inherited_interfaces] : hierarchy) {
+        known_interfaces->insert(intf);
+    }
+}
+
+Result<void> IsKnownInterface(const std::string& instance) {
+    FqInstance fqinstance;
+    if (!fqinstance.setTo(instance)) {
+        return Error() << "Unable to parse interface instance '" << instance << "'";
+    }
+    return IsKnownInterface(fqinstance.getFqName());
+}
+
+Result<void> IsKnownInterface(const FQName& intf) {
+    if (!known_interfaces) {
+        return Error() << "No known interfaces have been loaded.";
+    }
+    if (known_interfaces->count(intf) == 0) {
+        return Error() << "Interface is not in the known set of hidl_interfaces: '" << intf.string()
+                       << "'. Please ensure the interface is spelled correctly and built "
+                       << "by a hidl_interface target.";
+    }
+    return {};
+}
+
+}  // namespace init
+}  // namespace android