Merge lp:~thomas-voss/trust-store/add-click-based-package-name-query into lp:trust-store

[Thomas Voß]

Add an interface to installed click packages.

Add an interface to installed click packages.

[lp:~thomas-voss/trust-store/add-click-based-package-name-query]

39. By Thomas Voß on 2014-08-26

More fixes.

Unmerged revisions

39. By Thomas Voß on 2014-08-26

More fixes.

38. By Thomas Voß on 2014-08-21

Add an interface to installed click packages.

=== modified file 'CMakeLists.txt'
--- CMakeLists.txt	2014-08-13 08:24:18 +0000
+++ CMakeLists.txt	2014-08-26 14:23:37 +0000
@@ -28,7 +28,7 @@
 ENDIF(CMAKE_BUILD_TYPE MATCHES [cC][oO][vV][eE][rR][aA][gG][eE])
 
 find_package(PkgConfig)
-find_package(Boost COMPONENTS program_options system REQUIRED)
+find_package(Boost COMPONENTS filesystem program_options system REQUIRED)
 
 option(
   TRUST_STORE_MIR_AGENT_ENABLED
@@ -45,6 +45,7 @@
 
 pkg_check_modules(GFLAGS libgflags REQUIRED)
 pkg_check_modules(GLOG libglog REQUIRED)
+pkg_check_modules(JSON_C json-c REQUIRED)
 pkg_check_modules(PROCESS_CPP process-cpp REQUIRED)
 
 set(TRUST_STORE_VERSION_MAJOR 1)
@@ -58,6 +59,7 @@
 
   ${GFLAGS_INCLUDE_DIRS}
   ${GLOG_INCLUDE_DIRS}
+  ${JSON_C_INCLUDE_DIRS}
   ${PROCESS_CPP_INCLUDE_DIRS}
 )
 

=== added file 'include/core/trust/click.h'
--- include/core/trust/click.h	1970-01-01 00:00:00 +0000
+++ include/core/trust/click.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,36 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CORE_TRUST_CLICK_H_
+#define CORE_TRUST_CLICK_H_
+
+#include <string>
+
+namespace core
+{
+namespace trust
+{
+namespace click
+{
+/** @brief A helper function that resolves an AppArmor confinement profile to an application name. */
+std::string localized_app_name_for_confinement_profile(const std::string& profile);
+}
+}
+}
+
+#endif // CORE_TRUST_CLICK_H_

=== modified file 'src/CMakeLists.txt'
--- src/CMakeLists.txt	2014-08-14 13:22:53 +0000
+++ src/CMakeLists.txt	2014-08-26 14:23:37 +0000
@@ -127,6 +127,33 @@
   core/trust/dbus/codec.h
   core/trust/dbus/interface.h
 
+  # The publicly exposed click helper
+  core/trust/click.cpp
+
+  # An internal implementation of the click spec
+  core/trust/click/database.h
+  core/trust/click/framework.h
+  core/trust/click/framework_registry.h
+  core/trust/click/manifest.h
+  core/trust/click/package.h
+
+  core/trust/click/deb822.h
+  core/trust/click/deb822.cpp
+
+  core/trust/click/paths.h
+  core/trust/click/paths.cpp
+
+  core/trust/click/index.h
+  core/trust/click/index.cpp
+
+  core/trust/click/in_memory_framework_registry.h
+  core/trust/click/in_memory_framework_registry.cpp
+  core/trust/click/file_system_database.h
+  core/trust/click/file_system_database.cpp
+  core/trust/click/file_system_resource_resolver.h
+
+  core/trust/click/json_object.h
+  core/trust/click/json_object.cpp
   # The default implementation leverages SQLite3 to persist
   # requests.
   core/trust/impl/sqlite3/store.cpp  
@@ -176,6 +203,7 @@
   ${DBUS_LIBRARIES}
   ${GFLAGS_LDFLAGS}
   ${GLOG_LDFLAGS}
+  ${JSON_C_LDFLAGS}
   ${LIBAPPARMOR_LDFLAGS}
   ${MIR_CLIENT_LDFLAGS}
   ${PROCESS_CPP_LDFLAGS}

=== added directory 'src/core/trust/click'
=== added file 'src/core/trust/click.cpp'
--- src/core/trust/click.cpp	1970-01-01 00:00:00 +0000
+++ src/core/trust/click.cpp	2014-08-26 14:23:37 +0000
@@ -0,0 +1,58 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#include <core/trust/click.h>
+
+#include <core/trust/click/index.h>
+
+#include <regex>
+
+namespace
+{
+click::Index click_index{click::Index::Configuration{}};
+}
+
+std::string core::trust::click::localized_app_name_for_confinement_profile(const std::string& profile)
+{
+    // Please see https://wiki.ubuntu.com/AppStore/Interfaces/ApplicationId.
+    static const std::regex regex{"(.*)_(.*)_(.*)"};
+    static constexpr std::size_t index_package{1};
+    static constexpr std::size_t index_app{2};
+
+    // We store our matches here.
+    std::smatch match;
+
+    // See if the profile matches the pattern described in
+    // https://wiki.ubuntu.com/AppStore/Interfaces/ApplicationId
+    if (not std::regex_match(profile, match, regex)) throw std::runtime_error
+    {
+        "Profile " + profile + " does not match expected pattern"
+    };
+
+    auto current_version = click_index.find_package_for_name(match[index_package])->current_version();
+
+    auto& installed_version = current_version->resolve_to_installed_version_or_throw();
+
+    auto dot_desktop_file_name =
+            std::string{match[index_package]} + "_" + std::string{match[index_app]} + ".desktop";
+    auto dot_desktop_file = installed_version.resolve_named_resource(dot_desktop_file_name);
+
+    std::cout << dot_desktop_file << std::endl;
+
+    return "lalelu";
+}

=== added file 'src/core/trust/click/database.cpp'
=== added file 'src/core/trust/click/database.h'
--- src/core/trust/click/database.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/database.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,53 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_DATABASE_H_
+#define CLICK_DATABASE_H_
+
+#include <core/trust/click/package.h>
+
+#include <functional>
+#include <memory>
+
+namespace click
+{
+struct FrameworkRegistry;
+
+/** @brief Abstracts an enumerateable and queryable collection of click::Package's */
+struct Database
+{
+    /** @brief To save some typing. */
+    typedef std::shared_ptr<Database> Ptr;
+
+    /** @brief Functor called for every package in a database. */
+    typedef std::function<void(const Package::Ptr&)> PackageEnumerator;
+
+    /** @cond */
+    Database() = default;
+    virtual ~Database() = default;
+    /** @endcond */
+
+    /** @brief Enumerates all packages known to a database instance. */
+    virtual void enumerate_packages(const PackageEnumerator& enumerator) const = 0;
+
+    /** @brief Tries to lookup a package in the database. */
+    virtual Package::Ptr find_package_for_name(const std::string& package_name) const = 0;
+};
+}
+
+#endif // CLICK_DATABASE_H_

=== added file 'src/core/trust/click/database_of_installed_packages.h'
=== added file 'src/core/trust/click/deb822.cpp'
--- src/core/trust/click/deb822.cpp	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/deb822.cpp	2014-08-26 14:23:37 +0000
@@ -0,0 +1,50 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#include <core/trust/click/deb822.h>
+
+#include <istream>
+#include <regex>
+
+std::map<std::string, std::string> click::deb822::parse_from_stream(std::istream& in)
+{
+    // Matches the entirely blank line
+    static const std::regex blank_re{R"foo(^[[:space:]]*$)foo"};
+    // Matches key:value lines
+    static const std::regex line_re{R"foo(^([^\s]+)\s*:\s*([^\s]*)\s*)foo"};
+    static const std::size_t index_key{1};
+    static const std::size_t index_value{2};
+
+    std::map<std::string, std::string> result;
+
+    std::smatch match;
+    std::string line;
+
+    while (std::getline(in, line))
+    {
+        if (std::regex_match(line, blank_re))
+            continue;
+
+        if (std::regex_match(line, match, line_re))
+        {
+            result[match[index_key]] = match[index_value];
+        }
+    }
+
+    return result;
+}

=== added file 'src/core/trust/click/deb822.h'
--- src/core/trust/click/deb822.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/deb822.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,35 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_DEB822_H_
+#define CLICK_DEB822_H_
+
+#include <iosfwd>
+#include <map>
+#include <string>
+
+namespace click
+{
+namespace deb822
+{
+// A simple Deb822 parser for single-line, non-folded formats.
+std::map<std::string, std::string> parse_from_stream(std::istream& in);
+}
+}
+
+#endif // CLICK_DEB822_H_

=== added file 'src/core/trust/click/file_system_database.cpp'
--- src/core/trust/click/file_system_database.cpp	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/file_system_database.cpp	2014-08-26 14:23:37 +0000
@@ -0,0 +1,192 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#include <core/trust/click/file_system_database.h>
+
+#include <core/trust/click/framework_registry.h>
+#include <core/trust/click/manifest.h>
+#include <core/trust/click/package.h>
+
+// Just a helper
+#include <core/trust/click/json_object.h>
+
+#include <fstream>
+
+namespace
+{
+struct FilesystemPackage
+        : public click::Package,
+          public std::enable_shared_from_this<FilesystemPackage>
+{
+    struct FilesystemVersion : public click::installed::Version
+    {
+        struct Configuration
+        {
+            click::Package::Ptr parent;
+            boost::filesystem::path root;
+            click::FrameworkRegistry::Ptr framework_registry;
+        };
+
+        FilesystemVersion(const Configuration& configuration)
+            : configuration(configuration)
+        {
+            if (not boost::filesystem::is_directory(configuration.root)) throw std::logic_error
+            {
+                "Path has to be a directory: " + configuration.root.string()
+            };
+
+            std::ifstream in{(configuration.root / ".click" / "info" / (configuration.parent->name() + ".manifest")).string().c_str()};
+            std::string contents{std::istream_iterator<char>(in), std::istream_iterator<char>()};
+
+            auto object = json::Object::parse_from_string(contents);
+
+            manifest.installed_size = object.get(click::Manifest::Json::installed_size).to_int64();
+            manifest.required_frameworks.insert(
+                    configuration.framework_registry->find_framework_for_base_name(
+                        object.get(click::Manifest::Json::framework).to_string()));
+        }
+
+        click::installed::Version& resolve_to_installed_version_or_throw() override
+        {
+            return *this;
+        }
+
+        Package& parent() override
+        {
+            return *configuration.parent;
+        }
+
+        std::string specifier() override
+        {
+            return configuration.root.filename().string();
+        }
+
+        boost::filesystem::path resolve_named_resource(const std::string& resource) override
+        {
+            return configuration.root / resource;
+        }
+
+        std::size_t size() override
+        {
+            return manifest.installed_size;
+        }
+
+        void enumerate_required_frameworks(click::Package::Version::FrameworkEnumerator enumerator) override
+        {
+            for (const auto& framework : manifest.required_frameworks)
+                enumerator(framework);
+        }
+
+        Configuration configuration;
+
+        struct
+        {
+            std::int64_t installed_size;
+            std::set<click::Framework::Ptr> required_frameworks;
+        } manifest;
+    };
+
+    struct Configuration
+    {
+        boost::filesystem::path root;
+        click::FrameworkRegistry::Ptr framework_registry;
+    };
+
+    FilesystemPackage(const Configuration& configuration) : configuration(configuration)
+    {
+        if (not boost::filesystem::is_directory(configuration.root)) throw std::logic_error
+        {
+            "Path has to be a directory: " + configuration.root.string()
+        };
+    }
+
+    std::string name() override
+    {
+        return configuration.root.filename().string();
+    }
+
+    void enumerate_versions(click::Package::VersionEnumerator enumerator) override
+    {
+        boost::filesystem::directory_iterator it{configuration.root}, itE;
+
+        for (; it != itE; ++it)
+        {
+            // We post-process all symlinks and just store them during this iteration.
+            if (boost::filesystem::is_symlink(*it))
+                continue;
+
+            enumerator(std::make_shared<FilesystemVersion>(
+                           FilesystemVersion::Configuration
+                           {
+                               shared_from_this(),
+                               *it,
+                               configuration.framework_registry
+                           }));
+        }
+    }
+
+    Version::Ptr current_version() override
+    {
+        auto path = boost::filesystem::read_symlink(configuration.root / "current");
+
+        if (not boost::filesystem::is_directory(path)) throw std::runtime_error
+        {
+            "Could not resolve current version of package"
+        };
+
+        return std::make_shared<FilesystemVersion>(FilesystemVersion::Configuration
+        {
+            shared_from_this(),
+            path,
+            configuration.framework_registry
+        });
+    }
+
+    Configuration configuration;
+};
+}
+
+click::FileSystemDatabase::FileSystemDatabase(const Configuration& config)
+    : root{config.path},
+      framework_registry{config.framework_registry}
+{
+    if (not boost::filesystem::exists(root)) throw std::logic_error
+    {
+        "Cannot operate on non-existant directory: " + config.path
+    };
+
+    if (not boost::filesystem::is_directory(root)) throw std::logic_error
+    {
+        "Cannot operator on file: " + config.path
+    };
+}
+
+void click::FileSystemDatabase::enumerate_packages(const click::Database::PackageEnumerator& enumerator) const
+{
+    boost::filesystem::directory_iterator it{root}, itE{};
+
+    for (; it != itE; ++it)
+        enumerator(std::make_shared<FilesystemPackage>(
+                       FilesystemPackage::Configuration{*it, framework_registry}));
+}
+
+click::Package::Ptr click::FileSystemDatabase::find_package_for_name(const std::string& package_name) const
+{
+    return std::make_shared<FilesystemPackage>(FilesystemPackage::Configuration{root / package_name, framework_registry});
+}
+

=== added file 'src/core/trust/click/file_system_database.h'
--- src/core/trust/click/file_system_database.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/file_system_database.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,61 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_FILE_SYSTEM_DATABASE_H_
+#define CLICK_FILE_SYSTEM_DATABASE_H_
+
+#include <core/trust/click/database.h>
+
+#include <core/trust/click/file_system_resource_resolver.h>
+
+#include <boost/filesystem.hpp>
+
+namespace click
+{
+// An implementation of the Database interface using the filesystem as repository
+// for click packages.
+class FileSystemDatabase : public Database
+{
+public:
+    // To save some typing.
+    typedef std::shared_ptr<FileSystemDatabase> Ptr;
+
+    // Creation time options go here.
+    struct Configuration
+    {
+        // Root path of the database.
+        std::string path;
+        // FrameworkRegistry instance for resolving framework base names.
+        std::shared_ptr<FrameworkRegistry> framework_registry;
+    };
+
+    // Creates a new instance with the given root path.
+    // Throws if the root path does not exist or does not refer to a directory.
+    FileSystemDatabase(const Configuration& Configuration);
+
+    // From Database.
+    void enumerate_packages(const Database::PackageEnumerator& enumerator) const override;
+    Package::Ptr find_package_for_name(const std::string& package_name) const override;
+
+private:
+    boost::filesystem::path root;
+    std::shared_ptr<FrameworkRegistry> framework_registry;
+};
+}
+
+#endif // CLICK_FILE_SYSTEM_DATABASE_H_

=== added file 'src/core/trust/click/file_system_resource_resolver.h'
--- src/core/trust/click/file_system_resource_resolver.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/file_system_resource_resolver.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,44 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_FILE_SYSTEM_RESOURCE_RESOLVER_H_
+#define CLICK_FILE_SYSTEM_RESOURCE_RESOLVER_H_
+
+#include <core/trust/click/package.h>
+
+#include <boost/filesystem.hpp>
+
+namespace click
+{
+/** @brief Abstracts lookup of package resources in locally available filesystems. */
+struct FileSystemResourceResolver
+{
+    /** @brief A descriptor for resources contained in a specific version of a click package. */
+    typedef boost::filesystem::path ResourceDescriptor;
+
+    /** @cond */
+    FileSystemResourceResolver() = default;
+    virtual ~FileSystemResourceResolver() = default;
+    /** @endcond */
+
+    /** @brief Resolves a resource in a package version. */
+    virtual ResourceDescriptor resolve_named_resource_in_package_version(const std::string& resource_name, const Package::Version& version) = 0;
+};
+}
+
+#endif // CLICK_FILE_SYSTEM_RESOURCE_RESOLVER_H_

=== added file 'src/core/trust/click/framework.cpp'
=== added file 'src/core/trust/click/framework.h'
--- src/core/trust/click/framework.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/framework.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,53 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_FRAMEWORK_H_
+#define CLICK_FRAMEWORK_H_
+
+#include <memory>
+#include <string>
+
+namespace click
+{
+/** @brief Click Frameworks are "contracts" between the platform (OS) and apps. */
+struct Framework
+{
+    /** @brief To save some typing. */
+    typedef std::shared_ptr<Framework> Ptr;
+
+    /**
+     * @brief Compile-time constants for the keys in a .framework file.
+     *
+     * The file is in Deb822 format.
+     */
+    struct Keys
+    {
+        Keys() = delete;
+
+        static constexpr const char* base_name{"Base-Name"};
+        static constexpr const char* base_version{"Base-Version"};
+    };
+
+    /** @brief The 'base name' of the framework is here to permit click to support a wider range of underlying software than Ubuntu for phones in future. */
+    std::string base_name;
+    /** @brief The 'base version' of the framework is determined by the release of Ubuntu that the framework first targeted. */
+    std::string base_version;
+};
+}
+
+#endif // CLICK_FRAMEWORK_H_

=== added file 'src/core/trust/click/framework_registry.h'
--- src/core/trust/click/framework_registry.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/framework_registry.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,44 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_FRAMEWORK_REGISTRY_H_
+#define CLICK_FRAMEWORK_REGISTRY_H_
+
+#include <memory>
+
+namespace click
+{
+struct Framework;
+
+/** @brief Keeps track of all installed frameworks. */
+struct FrameworkRegistry
+{
+    /** @brief To save some typing. */
+    typedef std::shared_ptr<FrameworkRegistry> Ptr;
+
+    /** @cond */
+    FrameworkRegistry() = default;
+    virtual ~FrameworkRegistry() = default;
+    /** @endcond */
+
+    /** @brief Returns the framework corresponding to the given base_name or throws. */
+    virtual std::shared_ptr<Framework> find_framework_for_base_name(const std::string& base_name) const = 0;
+};
+}
+
+#endif // CLICK_FRAMEWORK_REGISTRY_H_

=== added file 'src/core/trust/click/in_memory_framework_registry.cpp'
--- src/core/trust/click/in_memory_framework_registry.cpp	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/in_memory_framework_registry.cpp	2014-08-26 14:23:37 +0000
@@ -0,0 +1,43 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#include <core/trust/click/in_memory_framework_registry.h>
+
+#include <core/trust/click/framework.h>
+
+void click::InMemoryFrameworkRegistry::register_framework(const std::shared_ptr<click::Framework>& framework)
+{
+    frameworks[framework->base_name] = framework;
+}
+
+void click::InMemoryFrameworkRegistry::unregister_framework(const std::shared_ptr<click::Framework>& framework)
+{
+    frameworks.erase(framework->base_name);
+}
+
+std::shared_ptr<click::Framework> click::InMemoryFrameworkRegistry::find_framework_for_base_name(const std::string& base_name) const
+{
+    auto it = frameworks.find(base_name);
+
+    if (it == frameworks.end()) throw std::out_of_range
+    {
+        "No entry for " + base_name
+    };
+
+    return it->second;
+}

=== added file 'src/core/trust/click/in_memory_framework_registry.h'
--- src/core/trust/click/in_memory_framework_registry.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/in_memory_framework_registry.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,53 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_IN_MEMORY_FRAMEWORK_REGISTRY_H_
+#define CLICK_IN_MEMORY_FRAMEWORK_REGISTRY_H_
+
+#include <core/trust/click/framework_registry.h>
+
+#include <memory>
+#include <unordered_map>
+
+namespace click
+{
+struct Framework;
+
+// Implements FrameworkRegistry using a hash-map.
+class InMemoryFrameworkRegistry : public FrameworkRegistry
+{
+public:
+    // To save some typing
+    typedef std::shared_ptr<InMemoryFrameworkRegistry> Ptr;
+
+    InMemoryFrameworkRegistry() = default;
+
+    // Allow for registering ...
+    void register_framework(const std::shared_ptr<Framework>& framework);
+    // and unregistering frameworks.
+    void unregister_framework(const std::shared_ptr<Framework>& framework);
+
+    // From FrameworkRegistry.
+    std::shared_ptr<Framework> find_framework_for_base_name(const std::string& base_name) const override;
+
+private:
+    std::unordered_map<std::string, std::shared_ptr<Framework>> frameworks;
+};
+}
+
+#endif // CLICK_IN_MEMORY_FRAMEWORK_REGISTRY_H_

=== added file 'src/core/trust/click/index.cpp'
--- src/core/trust/click/index.cpp	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/index.cpp	2014-08-26 14:23:37 +0000
@@ -0,0 +1,86 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#include <core/trust/click/index.h>
+
+#include <core/trust/click/deb822.h>
+
+#include <boost/filesystem.hpp>
+#include <boost/property_tree/ini_parser.hpp>
+#include <boost/property_tree/ptree.hpp>
+
+// Constructs a new instance, querying filesystem path setups
+click::Index::Index(const click::Index::Configuration& configuration)
+{
+    // Iterate over all known frameworks.
+    boost::filesystem::directory_iterator it{configuration.paths->default_frameworks_config_dir()}, itE;
+    for (; it != itE; ++it)
+    {
+        std::ifstream in{it->path().string().c_str()};
+        auto kv = click::deb822::parse_from_stream(in);
+
+        if (kv.count(click::Framework::Keys::base_name) == 0 || kv.count(click::Framework::Keys::base_version) == 0)
+            continue;
+
+        framework_registry->register_framework(Framework::Ptr
+        {
+            new Framework
+            {
+                kv.at(click::Framework::Keys::base_name),
+                kv.at(click::Framework::Keys::base_version)
+            }
+        });
+    }
+
+    // Iterate over all configured databases.
+    boost::filesystem::directory_iterator itd{configuration.paths->default_database_config_dir()}, itdE;
+    for (; itd != itdE; ++itd)
+    {
+        boost::property_tree::ptree ptree;
+        boost::property_tree::ini_parser::read_ini(itd->path().string(), ptree);
+
+        auto root = ptree.get_child("Click Database").get<std::string>("root");
+        databases.push_back(std::make_shared<click::FileSystemDatabase>(
+            click::FileSystemDatabase::Configuration{root, framework_registry}
+        ));
+    }
+}
+
+// From Database
+void click::Index::enumerate_packages(const click::Database::PackageEnumerator& enumerator) const
+{
+    for(auto database : databases)
+    {
+        database->enumerate_packages(enumerator);
+    }
+}
+
+click::Package::Ptr click::Index::find_package_for_name(const std::string& name) const
+{
+    for(auto database : databases)
+    {
+        try
+        {
+            return database->find_package_for_name(name);
+        } catch(...)
+        {
+        }
+    }
+    return click::Package::Ptr{};
+}
+

=== added file 'src/core/trust/click/index.h'
--- src/core/trust/click/index.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/index.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,70 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_INDEX_H_
+#define CLICK_INDEX_H_
+
+#include <core/trust/click/file_system_database.h>
+#include <core/trust/click/paths.h>
+
+#include <core/trust/click/in_memory_framework_registry.h>
+
+#include <boost/filesystem.hpp>
+
+#include <memory>
+
+namespace click
+{
+// Ties together multiple parts of the click world and renders
+// them readily accessible by implementing click::Database.
+class Index: public click::Database,
+             public std::enable_shared_from_this<Index>
+{
+public:
+    // Creation time arguments go here.
+    struct Configuration
+    {
+        // Provides the path configuration to the index.
+        Paths::Ptr paths
+        {
+            std::make_shared<click::Paths>()
+        };
+    };
+
+    // Constructs a new instance, querying filesystem path setups
+    Index(const Configuration& configuration);
+
+    // From Database
+    void enumerate_packages(const PackageEnumerator& enumerator) const override;
+    Package::Ptr find_package_for_name(const std::string& package_name) const override;
+
+private:
+    // Keeps track of all known frameworks
+    InMemoryFrameworkRegistry::Ptr framework_registry
+    {
+        std::make_shared<InMemoryFrameworkRegistry>()
+    };
+    // Sorted in descending order of priority.
+    std::vector<FileSystemDatabase::Ptr> databases
+    {
+        // Empty by default
+    };
+};
+}
+
+#endif // CLICK_INDEX_H_

=== added file 'src/core/trust/click/json_object.cpp'
--- src/core/trust/click/json_object.cpp	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/json_object.cpp	2014-08-26 14:23:37 +0000
@@ -0,0 +1,191 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#include <core/trust/click/json_object.h>
+
+#include <json-c/json.h>
+
+#include <stdexcept>
+
+namespace json
+{
+Object Object::parse_from_string(const std::string& s)
+{
+    return Object{json_tokener_parse(s.c_str())};
+}
+
+Object Object::create_array()
+{
+    return Object{json_object_new_array()};
+}
+
+Object Object::create_object()
+{
+    return Object{json_object_new_object()};
+}
+
+Object::Object(json_object* object) : object(object)
+{
+}
+
+Object::Object(const Object& rhs) : object(json_object_get(rhs.object))
+{
+}
+
+Object::~Object()
+{
+    json_object_put(object);
+}
+
+Object& Object::operator=(const Object& rhs)
+{
+    json_object_put(object);
+    object = json_object_get(rhs.object);
+
+    return *this;
+}
+
+std::string Object::to_plain_string()
+{
+    return std::string
+    {
+        json_object_to_json_string_ext(object, JSON_C_TO_STRING_PLAIN)
+    };
+}
+
+Object Object::get(const std::string& name) const
+{
+    json_object* result{nullptr};
+
+    json_object_object_get_ex(object, name.c_str(), &result);
+
+    if (not result) throw std::out_of_range
+    {
+        name.c_str()
+    };
+
+    return Object{result};
+}
+
+namespace
+{
+template<json_type type> void throw_if_type_mismatch(json_object* object)
+{
+    if (not json_object_is_type(object, type)) throw std::logic_error
+    {
+        "Type mismatch."
+    };
+}
+}
+// Attempts to resolve the object to a boolean value.
+// Throws std::logic_error in case of type mismatches.
+bool Object::to_bool() const
+{
+    throw_if_type_mismatch<json_type_boolean>(object);
+    return json_object_get_boolean(object);
+}
+
+std::int32_t Object::to_int32() const
+{
+    throw_if_type_mismatch<json_type_int>(object);
+    return json_object_get_int(object);
+}
+
+std::int64_t Object::to_int64() const
+{
+    throw_if_type_mismatch<json_type_int>(object);
+    return json_object_get_int64(object);
+}
+
+double Object::to_double() const
+{
+    throw_if_type_mismatch<json_type_double>(object);
+    return json_object_get_double(object);
+}
+
+std::string Object::to_string() const
+{
+    throw_if_type_mismatch<json_type_string>(object);
+    return std::string{json_object_get_string(object)};
+}
+
+void Object::put_array(const std::string& name, Object array)
+{
+    json_object_object_add(object, name.c_str(), json_object_get(array.object));
+}
+
+void Object::put_object(const std::string& name, Object other)
+{
+    json_object_object_add(object, name.c_str(), json_object_get(other.object));
+}
+
+void Object::put_boolean(const std::string& name, bool value)
+{
+    json_object_object_add(object, name.c_str(), json_object_new_boolean(value));
+}
+
+void Object::put_int32(const std::string& name, std::int32_t value)
+{
+    json_object_object_add(object, name.c_str(), json_object_new_int(value));
+}
+
+void Object::put_int64(const std::string& name, std::int64_t value)
+{
+    json_object_object_add(object, name.c_str(), json_object_new_int64(value));
+}
+
+void Object::put_double(const std::string& name, double value)
+{
+    json_object_object_add(object, name.c_str(), json_object_new_double(value));
+}
+
+void Object::put_string(const std::string& name, const std::string& value)
+{
+    json_object_object_add(object, name.c_str(), json_object_new_string_len(value.c_str(), value.size()));
+}
+
+std::size_t Object::array_size() const
+{
+    throw_if_type_mismatch<json_type_array>(object);
+    return json_object_array_length(object);
+}
+
+void Object::append(Object other)
+{
+    throw_if_type_mismatch<json_type_array>(object);
+    json_object_array_add(object, json_object_get(other.object));
+}
+
+void Object::put_object_for_index(std::size_t index, Object other)
+{
+    throw_if_type_mismatch<json_type_array>(object);
+    json_object_array_put_idx(object, index, json_object_get(other.object));
+}
+
+// Queries the object at index 'index'.
+// Throws std::logic_error if the object does not represent an array.
+// Throws std::out_of_range if the index exceeds the bounds of the array.
+Object Object::get_object_for_index(std::size_t index)
+{
+    throw_if_type_mismatch<json_type_array>(object);
+    return Object
+    {
+        json_object_get(json_object_array_get_idx(object, index))
+    };
+}
+}

=== added file 'src/core/trust/click/json_object.h'
--- src/core/trust/click/json_object.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/json_object.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,114 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_JSON_OBJECT_H_
+#define CLICK_JSON_OBJECT_H_
+
+#include <cstdint>
+
+#include <string>
+
+// Forward declare the opaque json_object handle from json-c here.
+struct json_object;
+
+// We are wrapping libjson-c and introduce a generic Object type for that purpose.
+namespace json
+{
+// For internal purposes only
+class Object
+{
+public:
+    // Parses a new object from the given string.
+    // Throws std::runtime_error in case of parsing errors.
+    static Object parse_from_string(const std::string& s);
+    // Creates a new object of type array.
+    static Object create_array();
+    // Creates a new object of type object.
+    static Object create_object();
+
+    // Shallow copy, only increments reference count.
+    Object(const Object& rhs);
+    // Decrements the reference count of the object.
+    ~Object();
+
+    // Shallow copy, decrements reference count of this object,
+    // increments reference count of object contained in rhs.
+    Object& operator=(const Object& rhs);
+
+    // Encodes this object instance as a valid JSON string without any
+    // unneccessary whitespace
+    std::string to_plain_string();
+
+    // Resolves the object with the given name.
+    // Throws std::out_of_range if no object with the given name is known.
+    Object get(const std::string& name) const;
+
+    // Attempts to resolve the object to a boolean value.
+    // Throws std::logic_error in case of type mismatches.
+    bool to_bool() const;
+    // Attempts to resolve the object to an integer value of 32bit width.
+    // Throws std::logic_error in case of type mismatches.
+    std::int32_t to_int32() const;
+    // Attempts to resolve the object to an integer value of 64bit width.
+    // Throws std::logic_error in case of type mismatches.
+    std::int64_t to_int64() const;
+    // Attempts to resolve the object to a floating point value.
+    // Throws std::logic_error in case of type mismatches.
+    double to_double() const;
+    // Attempts to resolve the object to a string value.
+    // Throws std::logic_error in case of type mismatches.
+    std::string to_string() const;
+
+    // Adds the given array under the given name to this object instance.
+    void put_array(const std::string& name, Object array);
+    // Adds the given object under the given name to this object instance.
+    void put_object(const std::string& name, Object other);
+    // Adds the given boolean under the given name to this object instance.
+    void put_boolean(const std::string& name, bool value);
+    // Adds the given integer under the given name to this object instance.
+    void put_int32(const std::string& name, std::int32_t value);
+    // Adds the given integer under the given name to this object instance.
+    void put_int64(const std::string& name, std::int64_t value);
+    // Adds the given floating point value under the given name to this object instance.
+    void put_double(const std::string& name, double value);
+    // Adds the given string value under the given name to this object instance.
+    void put_string(const std::string& name, const std::string& value);
+
+    // Only valid for array objects
+    // Returns the size of the array, throws std::logic_error if the object
+    // does not represent an array.
+    std::size_t array_size() const;
+    // Appends an object to the end of the array, throws std::logic_error if
+    // the object does not represent an array.
+    void append(Object other);
+    // Replaces the object at index 'index' with the given instance.
+    // Throws std::logic_error if the object does not represent an array.
+    // Throws std::out_of_range if the index exceeds the bounds of the array.
+    void put_object_for_index(std::size_t index, Object other);
+    // Queries the object at index 'index'.
+    // Throws std::logic_error if the object does not represent an array.
+    // Throws std::out_of_range if the index exceeds the bounds of the array.
+    Object get_object_for_index(std::size_t index);
+
+private:
+    Object(json_object* object);
+    json_object* object;
+};
+}
+
+#endif // CLICK_JSON_OBJECT_H_

=== added file 'src/core/trust/click/manifest.h'
--- src/core/trust/click/manifest.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/manifest.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,65 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_MANIFEST_H_
+#define CLICK_MANIFEST_H_
+
+namespace click
+{
+/**
+ * @brief Describes the click package contents, in JSON format.
+ *
+ * Please see http://click.readthedocs.org/en/latest/file-format.html#manifest
+ *
+ */
+struct Manifest
+{
+    /** @brief Enumerates all known JSON keys. */
+    struct Json
+    {
+        Json() = delete;
+
+        /** @brief Unique name for the application. */
+        static constexpr const char* name {"name"};
+        /** @brief Version number of the application. */
+        static constexpr const char* version {"version"};
+        /** @brief The system framework(s) for which the package was built. */
+        static constexpr const char* framework {"framework"};
+        /** @brief The size of the unpacked package in KiB. */
+        static constexpr const char* installed_size {"installed-size"};
+
+        /** @brief Short (one-line) synopsis of the application. */
+        static constexpr const char* title {"title"};
+        /** @brief Extended description of the application; may be multi-paragraph. */
+        static constexpr const char* description {"description"};
+        /** @brief Name and email address of maintainer of the application. */
+        static constexpr const char* maintainer {"maintainer"};
+        /**
+         * @brief Icon to display in interfaces listing click packages.
+         *
+         * If the name refers to an existing file when resolved relative to the
+         * base directory of the package, the given file will be used; if not,
+         * the algorithm described in the Icon Theme Specification will be used
+         * to locate the icon
+         */
+        static constexpr const char* icon {"icon"};
+    };
+};
+}
+
+#endif // CLICK_MANIFEST_H_

=== added file 'src/core/trust/click/package.h'
--- src/core/trust/click/package.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/package.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,103 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_PACKAGE_H_
+#define CLICK_PACKAGE_H_
+
+#include <core/trust/click/framework.h>
+
+#include <boost/filesystem.hpp>
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+
+namespace click
+{
+namespace installed
+{
+struct Version;
+}
+/** @brief A click package. */
+struct Package
+{
+    /** @brief To save some typing. */
+    typedef std::shared_ptr<Package> Ptr;
+
+    /** @brief A specific version of a package. */
+    struct Version
+    {
+        /** @brief To save some typing. */
+        typedef std::shared_ptr<Version> Ptr;
+
+        /** @brief Functor invoked for every required framework. */
+        typedef std::function<void(const Framework::Ptr&)> FrameworkEnumerator;
+
+        /** @cond */
+        Version() = default;
+        virtual ~Version() = default;
+        /** @endcond */
+
+        /** @brief Parent package of this specific version. */
+        virtual Package&  parent() = 0;
+
+        /** @brief Version number of the package. */
+        virtual std::string specifier() = 0;
+
+        /** @brief Frameworks required by this specific version of the package. */
+        virtual void enumerate_required_frameworks(FrameworkEnumerator) = 0;
+
+        /** @brief Returns the installed details if the package is installed or throws. */
+        virtual installed::Version& resolve_to_installed_version_or_throw() = 0;
+    };
+
+    /** @brief Functor invoked for every known version of the package. */
+    typedef std::function<void(const Version::Ptr&)> VersionEnumerator;
+
+    /** @cond */
+    Package() = default;
+    virtual ~Package() = default;
+    /** @endcond */
+
+    /** @brief Unique name of the package. */
+    virtual std::string name() = 0;
+
+    /** @brief All known versions of the package. */
+    virtual void enumerate_versions(VersionEnumerator) = 0;
+
+    /** @brief Queries the current version of the package. */
+    virtual Version::Ptr current_version() = 0;
+};
+
+namespace installed
+{
+/** @brief Marks an installed, locally available version. */
+struct Version : public click::Package::Version
+{
+    /** @brief Resolves a resource in a package version. */
+    virtual boost::filesystem::path resolve_named_resource(const std::string& resource_name) = 0;
+
+    /** @brief Size of the unpackaged package in KiB. */
+    virtual std::size_t size() = 0;
+};
+}
+}
+
+#endif // CLICK_PACKAGE_H_

=== added file 'src/core/trust/click/paths.cpp'
--- src/core/trust/click/paths.cpp	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/paths.cpp	2014-08-26 14:23:37 +0000
@@ -0,0 +1,42 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#include <core/trust/click/paths.h>
+
+namespace
+{
+static constexpr const char* the_database_config_dir
+{
+    "/etc/click/databases"
+};
+
+static constexpr const char* the_frameworks_config_dir
+{
+    "/usr/share/click/frameworks"
+};
+}
+
+std::string click::Paths::default_database_config_dir() const
+{
+    return the_database_config_dir;
+}
+
+std::string click::Paths::default_frameworks_config_dir() const
+{
+    return the_frameworks_config_dir;
+}

=== added file 'src/core/trust/click/paths.h'
--- src/core/trust/click/paths.h	1970-01-01 00:00:00 +0000
+++ src/core/trust/click/paths.h	2014-08-26 14:23:37 +0000
@@ -0,0 +1,45 @@
+/*
+ * Copyright © 2014 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Thomas Voß <[e-mail]>
+ */
+
+#ifndef CLICK_PATHS_H_
+#define CLICK_PATHS_H_
+
+#include <memory>
+#include <string>
+
+namespace click
+{
+/** @brief Provides default settings for config directories. */
+struct Paths
+{
+    /** @brief To save some typing. */
+    typedef std::shared_ptr<Paths> Ptr;
+
+    /** @cond */
+    Paths() = default;
+    virtual ~Paths() = default;
+    /** @endcond */
+
+    /** @brief The default database config directory, i.e., /etc/click/databases */
+    virtual std::string default_database_config_dir() const;
+    /** @brief The default frameworks config directory, i.e., /usr/share/click/frameworks */
+    virtual std::string default_frameworks_config_dir() const;
+};
+}
+
+#endif // CLICK_PATHS_H_