cache entities to avoid allocations

Signed-off-by: Folling <mail@folling.io>

include/ikarus/errors.h

@@ -0,0 +1,71 @@
+#pragma once
+
+/// \file global.h
+/// \author Folling <folling@ikarus.world>
+
+#include <ikarus/macros.h>
+
+/// \addtogroup errors Errors
+/// \brief Error handling within libikarus
+/// \details Errors are stored for each project, akin to the errno handling in C.
+/// We store multiple pieces of information about the error occurring. For more information see
+/// #ikarus_project_get_error_message.
+/// @{
+
+IKARUS_BEGIN_HEADER
+
+/// \brief Delineates what caused an error.
+/// \details First 2 bytes delineate the major type, next 2 bytes delineate the minor type, next 4 bytes delineate the detail
+/// type.
+/// \remark Note that this doesn't show responsibility. An error with source "SubSystem" could still be the fault of
+/// libikarus.
+enum IkarusErrorInfo {
+    /// \brief No error occurred.
+    IkarusErrorInfo_Source_None = 0x0001000000000000,
+    /// \brief The error was caused by the client.
+    IkarusErrorInfo_Source_Client = 0x0001000000000001,
+    /// \brief The error was caused by a sub-system of libikarus.
+    IkarusErrorInfo_Source_SubSystem = 0x0001000000000002,
+    /// \brief The error was caused by libikarus itself.
+    IkarusErrorInfo_Source_LibIkarus = 0x0001000000000003,
+    /// \brief The error was caused by an unknown source.
+    IkarusErrorInfo_Source_Unknown = 0x00010000FFFFFFFF,
+    /// \brief No error occurred.
+    IkarusErrorInfo_Type_None = 0x0002000000000000,
+    /// \brief The user misused the API.
+    /// \example Accessing a resource that does not exist.
+    IkarusErrorInfo_Type_Client_Misuse = 0x0002000100000001,
+    /// \brief The user provided invalid input.
+    /// \example Passing null for a pointer that must not be null.
+    IkarusErrorInfo_Type_Client_Input = 0x0002000100000002,
+    /// \brief An error occurred while interacting with a dependency from ikarus.
+    /// \example An error occurred in the underlying OS library.
+    IkarusErrorInfo_Type_SubSystem_Dependency = 0x0002000200000001,
+    /// \brief An error occurred while interacting with the database.
+    /// \example An error occurred while executing a query.
+    IkarusErrorInfo_Type_SubSystem_Database = 0x0002000200000002,
+    /// \brief An error occurred while interacting with the filesystem.
+    /// \example An error occurred while reading a file.
+    IkarusErrorInfo_Type_SubSystem_Filesystem = 0x0002000200000003,
+    /// \brief A datapoint within ikarus is invalid for the current state of the system.
+    /// \example The name of an object is found to be invalid UTF8.
+    IkarusErrorInfo_Type_LibIkarus_InvalidState = 0x0002000300000001,
+    /// \brief LibIkarus is unable to perform a certain operation that should succeed.
+    /// \example Migrating a project fails
+    IkarusErrorInfo_Type_LibIkarus_CannotPerformOperation = 0x0002000300000002,
+    /// \brief LibIkarus is unable to perform a certain operation within a given timeframe.
+    /// \example A query takes longer than the timeout.
+    IkarusErrorInfo_Type_LibIkarus_Timeout = 0x0002000300000003,
+    /// \brief The type of error is unknown.
+    IkarusErrorInfo_Type_Unknown = 0xFFFFFFFF,
+};
+
+/// \brief Gets the name of an error info.
+/// \param info The error info to get the name of.
+/// \return The name of the error info.
+/// \remark The returned pointer is valid for the lifetime of the program and must not be freed.
+IKA_API char const * get_error_info_name(IkarusErrorInfo info);
+
+IKARUS_END_HEADER
+
+/// @}

include/ikarus/global.h

@@ -1,6 +1,6 @@
 #pragma once
 
-/// \file memory.h
+/// \file global.h
 /// \author Folling <folling@ikarus.world>
 
 #include <ikarus/macros.h>
@@ -9,8 +9,12 @@
 /// \brief Information relevant to the entire library.
 /// @{
 
+IKARUS_BEGIN_HEADER
+
 /// \brief Frees a pointer allocated by ikarus. Every pointer returned by a function must be freed using this function unless
 /// explicitly stated otherwise.
 IKA_API void ikarus_free(void * ptr);
 
+IKARUS_END_HEADER
+
 /// @}

src/errors.cpp

@@ -0,0 +1,22 @@
+#include "ikarus/errors.h"
+
+char const * get_error_info_name(IkarusErrorInfo info) {
+    switch (info) {
+    case IkarusErrorInfo_Source_None: return "IkarusErrorSource_None";
+    case IkarusErrorInfo_Source_Client: return "IkarusErrorSource_Client";
+    case IkarusErrorInfo_Source_SubSystem: return "IkarusErrorSource_SubSystem";
+    case IkarusErrorInfo_Source_LibIkarus: return "IkarusErrorSource_LibIkarus";
+    case IkarusErrorInfo_Source_Unknown: return "IkarusErrorSource_Unknown";
+    case IkarusErrorInfo_Type_None: return "IkarusErrorType_None";
+    case IkarusErrorInfo_Type_Client_Misuse: return "IkarusErrorType_Client_Misuse";
+    case IkarusErrorInfo_Type_Client_Input: return "IkarusErrorType_Client_Input";
+    case IkarusErrorInfo_Type_SubSystem_Dependency: return "IkarusErrorType_SubSystem_Dependency";
+    case IkarusErrorInfo_Type_SubSystem_Database: return "IkarusErrorType_SubSystem_Database";
+    case IkarusErrorInfo_Type_SubSystem_Filesystem: return "IkarusErrorType_SubSystem_Filesystem";
+    case IkarusErrorInfo_Type_LibIkarus_InvalidState: return "IkarusErrorType_LibIkarus_InvalidState";
+    case IkarusErrorInfo_Type_LibIkarus_CannotPerformOperation: return "IkarusErrorType_LibIkarus_CannotPerformOperation";
+    case IkarusErrorInfo_Type_LibIkarus_Timeout: return "IkarusErrorType_LibIkarus_Timeout";
+    case IkarusErrorInfo_Type_Unknown: return "IkarusErrorType_Unknown";
+    default: return "Unknown";
+    }
+}

src/objects/blueprint.cpp

@@ -21,39 +21,56 @@ IkarusBlueprint * ikarus_blueprint_create(struct IkarusProject * project, char c
         return nullptr;
     }
 
-    LOG_VERBOSE("project={}; name={}", project->path.c_str(), name);
+    auto ctx = project->function_context();
 
     if (name == nullptr) {
-        LOG_ERROR("name is nullptr");
+        ctx->set_error("name is nullptr", true, IkarusErrorInfo_Source_Client, IkarusErrorInfo_Type_Client_Input);
         return nullptr;
     }
 
     if (cppbase::is_empty_or_blank(name)) {
-        LOG_ERROR("name is empty or blank");
+        ctx->set_error("name is empty or blank", true, IkarusErrorInfo_Source_Client, IkarusErrorInfo_Type_Client_Input);
         return nullptr;
     }
 
-    VTRYRV(auto id, nullptr, project->db->transact([name](auto * db) -> cppbase::Result<IkarusId, sqlitecpp::TransactionError> {
+    LOG_VERBOSE("project={}; name={}", project->path().c_str(), name);
+
+    VTRYRV(
+        auto id,
+        nullptr,
+        project->db()
+            ->transact([name](auto * db) -> cppbase::Result<IkarusId, sqlitecpp::TransactionError> {
                 LOG_VERBOSE("creating blueprint in objects table");
 
                 TRY(db->execute(
-            "INSERT INTO `objects` (`object_type`, `name`) VALUES(?, ?);", static_cast<int>(IkarusObjectType_Blueprint), name
+                    "INSERT INTO `objects` (`object_type`, `name`) VALUES(?, ?);",
+                    static_cast<int>(IkarusObjectType_Blueprint),
+                    name
                 ));
 
                 auto id = db->last_insert_rowid();
 
-        LOG_VERBOSE("blueprint is {}", id);
+                LOG_VERBOSE("id is {}", id);
 
                 LOG_VERBOSE("inserting blueprint into blueprints table");
 
                 TRY(db->execute("INSERT INTO `blueprints`(`id`) VALUES(?);", id));
 
                 return cppbase::ok(id);
-    }));
+            })
+            .on_error([ctx](auto const& err) {
+                ctx->set_error(
+                    fmt::format("unable to insert blueprint into database: {}", err),
+                    true,
+                    IkarusErrorInfo_Source_SubSystem,
+                    IkarusErrorInfo_Type_SubSystem_Database
+                );
+            })
+    );
 
     LOG_VERBOSE("successfully created blueprint");
 
-    return new IkarusBlueprint{project, id};
+    return project->get_blueprint(id);
 }
 
 void ikarus_blueprint_delete(IkarusBlueprint * blueprint) {
@@ -64,16 +81,27 @@ void ikarus_blueprint_delete(IkarusBlueprint * blueprint) {
         return;
     }
 
+    auto * ctx = blueprint->project->function_context();
+
     LOG_VERBOSE("blueprint={}", blueprint->id);
 
-    if (auto res = blueprint->project->db->execute("DELETE FROM `objects` WHERE `id` = ?", blueprint->id); res.is_err()) {
-        LOG_ERROR("failed to delete blueprint {} from objects table: {}", blueprint->id, res.unwrap_error());
-        return;
-    }
+    TRYRV(
+        ,
+        blueprint->project->db()
+            ->execute("DELETE FROM `objects` WHERE `id` = ?", blueprint->id)
+            .on_error([ctx](auto const& err) {
+                ctx->set_error(
+                    fmt::format("failed to delete blueprint from objects table: {}", err),
+                    true,
+                    IkarusErrorInfo_Source_SubSystem,
+                    IkarusErrorInfo_Type_SubSystem_Database
+                );
+            })
+    );
 
-    LOG_VERBOSE("blueprint was successfully deleted from database, freeing pointer");
+    LOG_VERBOSE("blueprint was successfully deleted from database, freeing blueprint");
 
-    delete blueprint;
+    blueprint->project->remove_blueprint(blueprint);
 
     LOG_VERBOSE("successfully deleted blueprint");
 }
@@ -86,14 +114,23 @@ size_t ikarus_blueprint_get_property_count(IkarusBlueprint const * blueprint) {
         return 0;
     }
 
+    auto * ctx = blueprint->project->function_context();
+
     LOG_VERBOSE("blueprint={}", blueprint->id);
 
     VTRYRV(
         auto count,
         0,
-        blueprint->project->db->query_one<int>(
-            "SELECT COUNT(*) FROM `blueprint_properties` WHERE `blueprint_id` = ?;", blueprint->id
-        )
+        blueprint->project->db()
+            ->query_one<int>("SELECT COUNT(*) FROM `blueprint_properties` WHERE `blueprint_id` = ?;", blueprint->id)
+            .on_error([ctx](auto const& err) {
+                ctx->set_error(
+                    fmt::format("failed to fetch blueprint property count: {}", err),
+                    true,
+                    IkarusErrorInfo_Source_SubSystem,
+                    IkarusErrorInfo_Type_SubSystem_Database
+                );
+            })
     );
 
     return static_cast<size_t>(count);
@@ -109,6 +146,8 @@ void ikarus_blueprint_get_properties(
         return;
     }
 
+    auto * ctx = blueprint->project->function_context();
+
     if (properties_out == nullptr) {
         LOG_ERROR("properties_out is nullptr");
         return;
@@ -118,17 +157,28 @@ void ikarus_blueprint_get_properties(
 
     IkarusId ids[properties_out_size];
 
-    if (auto res = blueprint->project->db->query_many_buffered<IkarusId>(
-            "SELECT `id` FROM `properties` WHERE `source` = ?", static_cast<IkarusId *>(ids), properties_out_size, blueprint->id
+    TRYRV(
+        ,
+        blueprint->project->db()
+            ->query_many_buffered<IkarusId>(
+                "SELECT `id` FROM `properties` WHERE `source` = ?",
+                static_cast<IkarusId *>(ids),
+                properties_out_size,
+                blueprint->id
+            )
+            .on_error([ctx](auto const& err) {
+                ctx->set_error(
+                    fmt::format("failed to fetch blueprint property ids: {}", err),
+                    true,
+                    IkarusErrorInfo_Source_SubSystem,
+                    IkarusErrorInfo_Type_SubSystem_Database
+                );
+            })
     );
-        res.is_err()) {
-        LOG_ERROR("failed to fetch blueprint property ids: {}", res.unwrap_error());
-        return;
-    }
 
     for (size_t i = 0; i < properties_out_size; ++i) {
         /// NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
-        properties_out[i] = new IkarusProperty{blueprint->project, ids[i]};
+        properties_out[i] = blueprint->project->get_property(ids[i]);
     }
 
     LOG_VERBOSE("successfully fetched blueprint properties");

src/objects/entity.hpp

@@ -3,4 +3,7 @@
 #include <objects/object.hpp>
 
 /// \private
-struct IkarusEntity : public IkarusObject {};
+struct IkarusEntity : public IkarusObject {
+    inline IkarusEntity(struct IkarusProject * project, IkarusId id):
+        IkarusObject{project, id} {}
+};

src/persistence/project.hpp

@@ -1,11 +1,148 @@
+#pragma once
+
+#include <concepts>
 #include <filesystem>
+#include <ranges>
+#include <stack>
 #include <string>
 
 #include <sqlitecpp/connection.hpp>
 
+#include <ikarus/errors.h>
+
+constexpr inline size_t MAXIMUM_ERROR_INFOS = 8;
+constexpr inline size_t MAXIMUM_ERROR_MESSAGE_LENGTH = 256;
+
+class FunctionContext {
+public:
+    explicit FunctionContext(struct IkarusProject * project);
+    FunctionContext(FunctionContext const&) noexcept = default;
+    FunctionContext(FunctionContext&&) noexcept = default;
+
+    auto operator=(FunctionContext const&) noexcept -> FunctionContext& = default;
+    auto operator=(FunctionContext&&) noexcept -> FunctionContext& = default;
+
+    ~FunctionContext();
+
+    template<typename... Infos>
+        requires(std::is_same_v<IkarusErrorInfo, Infos> && ...) && (sizeof...(Infos) <= MAXIMUM_ERROR_INFOS)
+    auto set_error(std::string_view error_message, bool log_error, Infos... infos) -> void;
+
+private:
+    struct IkarusProject * _project;
+};
+
 /// \private
 struct IkarusProject {
-    std::string name;
-    std::filesystem::path path;
-    std::unique_ptr<sqlitecpp::Connection> db;
+public:
+    [[nodiscard]] inline auto name() const -> std::string_view {
+        return _name;
+    }
+
+    [[nodiscard]] inline auto path() const -> std::filesystem::path const& {
+        return _path;
+    }
+
+    [[nodiscard]] inline auto db() -> sqlitecpp::Connection * {
+        return _db.get();
+    }
+
+    inline auto function_context() -> FunctionContext * {
+        return &_function_contexts.emplace(this);
+    }
+
+    [[nodiscard]] IkarusBlueprint * get_blueprint(IkarusId id) {
+        return get_cached_object(id, this->_blueprints);
+    }
+
+    auto remove_blueprint(IkarusBlueprint * blueprint) -> void {
+        remove_cached_object(blueprint, _blueprints);
+    }
+
+    [[nodiscard]] auto get_entity(IkarusId id) -> IkarusEntity * {
+        return get_cached_object(id, this->_entities);
+    }
+
+    auto remove_entity(IkarusEntity * entity) -> void {
+        remove_cached_object(entity, _entities);
+    }
+
+    [[nodiscard]] auto get_property(IkarusId id) -> IkarusProperty * {
+        return get_cached_object(id, this->_properties);
+    }
+
+    auto remove_property(IkarusProperty * property) -> void {
+        remove_cached_object(property, _properties);
+    }
+
+private:
+    template<typename T>
+    [[nodiscard]] T * get_cached_object(IkarusId id, std::unordered_map<IkarusId, std::unique_ptr<T>>& cache) {
+        if (auto iter = cache.find(id); iter == cache.cend()) {
+            auto [ret_iter, _] = cache.emplace(id, std::make_unique<T>(this, id));
+
+            return ret_iter->second.get();
+        } else {
+            return iter->second.get();
+        }
+    }
+
+    template<typename T>
+    void remove_cached_object(T * object, std::unordered_map<IkarusId, std::unique_ptr<T>>& cache) {
+        cache.erase(object->id);
+    }
+
+private:
+    friend class FunctionContext;
+
+    std::string _name;
+    std::filesystem::path _path;
+    std::unique_ptr<sqlitecpp::Connection> _db;
+
+    std::array<IkarusErrorInfo, MAXIMUM_ERROR_INFOS> error_infos;
+    std::string error_message_buffer;
+
+    std::unordered_map<IkarusId, std::unique_ptr<IkarusBlueprint>> _blueprints;
+    std::unordered_map<IkarusId, std::unique_ptr<IkarusProperty>> _properties;
+    std::unordered_map<IkarusId, std::unique_ptr<IkarusEntity>> _entities;
+
+    std::stack<FunctionContext> _function_contexts;
 };
+
+FunctionContext::FunctionContext(struct IkarusProject * project):
+    _project{project} {}
+
+FunctionContext::~FunctionContext() {
+    if (_project->_function_contexts.size() == 1) {
+        if (_project->error_message_buffer.empty()) {
+            _project->error_message_buffer.push_back('\0');
+        } else {
+            _project->error_message_buffer[0] = '\0';
+        }
+
+        _project->error_infos = {};
+    }
+
+    _project->_function_contexts.pop();
+}
+
+template<typename... Infos>
+    requires(std::is_same_v<IkarusErrorInfo, Infos> && ...) && (sizeof...(Infos) <= MAXIMUM_ERROR_INFOS)
+auto FunctionContext::set_error(std::string_view error_message, bool log_error, Infos... infos) {
+    if (error_message.size() > _project->error_message_buffer.size()) {
+        _project->error_message_buffer.resize(error_message.size() + 1);
+    }
+
+    for (int i = 0; i < error_message.size(); ++i) {
+        _project->error_message_buffer[i] = error_message[i];
+    }
+
+    _project->error_message_buffer[error_message.size()] = '\0';
+    _project->error_infos = {infos...};
+
+    if (log_error) {
+        LOG_ERROR(
+            "Error({}): {}", fmt::join(_project->error_infos | std::views::transform(get_error_info_name), ", "), error_message
+        );
+    }
+}