Merge pull request #7 from realm/tg-results

Port Results functionality from RLMResults

I will make the remaining fixes in another pr.

object_store.cpp

@@ -30,6 +30,7 @@
 
 using namespace realm;
 
+namespace {
 const char * const c_metadataTableName = "metadata";
 const char * const c_versionColumnName = "version";
 const size_t c_versionColumnIndex = 0;
@@ -42,8 +43,8 @@ const size_t c_primaryKeyPropertyNameColumnIndex =  1;
 
 const size_t c_zeroRowIndex = 0;
 
-const std::string c_object_table_prefix = "class_";
+const char c_object_table_prefix[] = "class_";
-const size_t c_object_table_prefix_length = c_object_table_prefix.length();
+}
 
 const uint64_t ObjectStore::NotVersioned = std::numeric_limits<uint64_t>::max();
 
@@ -119,15 +120,15 @@ void ObjectStore::set_primary_key_for_object(Group *group, StringData object_typ
     }
 }
 
-std::string ObjectStore::object_type_for_table_name(const std::string &table_name) {
+StringData ObjectStore::object_type_for_table_name(StringData table_name) {
-    if (table_name.size() >= c_object_table_prefix_length && table_name.compare(0, c_object_table_prefix_length, c_object_table_prefix) == 0) {
+    if (table_name.begins_with(c_object_table_prefix)) {
-        return table_name.substr(c_object_table_prefix_length, table_name.length() - c_object_table_prefix_length);
+        return table_name.substr(sizeof(c_object_table_prefix) - 1);
     }
-    return std::string();
+    return StringData();
 }
 
-std::string ObjectStore::table_name_for_object_type(const std::string &object_type) {
+std::string ObjectStore::table_name_for_object_type(StringData object_type) {
-    return c_object_table_prefix + object_type;
+    return std::string(c_object_table_prefix) + object_type.data();
 }
 
 TableRef ObjectStore::table_for_object_type(Group *group, StringData object_type) {
@@ -138,7 +139,7 @@ ConstTableRef ObjectStore::table_for_object_type(const Group *group, StringData
     return group->get_table(table_name_for_object_type(object_type));
 }
 
-TableRef ObjectStore::table_for_object_type_create_if_needed(Group *group, const StringData &object_type, bool &created) {
+TableRef ObjectStore::table_for_object_type_create_if_needed(Group *group, StringData object_type, bool &created) {
     return group->get_or_add_table(table_name_for_object_type(object_type), &created);
 }
 
@@ -494,7 +495,7 @@ void ObjectStore::validate_primary_column_uniqueness(const Group *group, Schema
     }
 }
 
-void ObjectStore::delete_data_for_object(Group *group, const StringData &object_type) {
+void ObjectStore::delete_data_for_object(Group *group, StringData object_type) {
     TableRef table = table_for_object_type(group, object_type);
     if (table) {
         group->remove_table(table->get_index_in_group());

object_store.hpp

@@ -68,11 +68,14 @@ namespace realm {
         static Schema schema_from_group(const Group *group);
 
         // deletes the table for the given type
-        static void delete_data_for_object(Group *group, const StringData &object_type);
+        static void delete_data_for_object(Group *group, StringData object_type);
 
         // indicates if this group contains any objects
         static bool is_empty(const Group *group);
 
+        static std::string table_name_for_object_type(StringData class_name);
+        static StringData object_type_for_table_name(StringData table_name);
+
     private:
         // set a new schema version
         static void set_schema_version(Group *group, uint64_t version);
@@ -102,9 +105,7 @@ namespace realm {
         // must be in write transaction to set
         static void set_primary_key_for_object(Group *group, StringData object_type, StringData primary_key);
 
-        static TableRef table_for_object_type_create_if_needed(Group *group, const StringData &object_type, bool &created);
+        static TableRef table_for_object_type_create_if_needed(Group *group, StringData object_type, bool &created);
-        static std::string table_name_for_object_type(const std::string &class_name);
-        static std::string object_type_for_table_name(const std::string &table_name);
 
         // returns if any indexes were changed
         static bool update_indexes(Group *group, Schema &schema);

results.cpp

@@ -1,44 +1,334 @@
-/* Copyright 2015 Realm Inc - All Rights Reserved
+////////////////////////////////////////////////////////////////////////////
- * Proprietary and Confidential
+//
- */
+// Copyright 2015 Realm Inc.
+//
+// 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 "results.hpp"
-#import <stdexcept>
+
+#include <stdexcept>
 
 using namespace realm;
 
-Results::Results(SharedRealm &r, ObjectSchema &o, Query q, SortOrder s) :
+#ifdef __has_cpp_attribute
-    realm(r), object_schema(o), backing_query(q), table_view(backing_query.find_all())
+#define REALM_HAS_CCP_ATTRIBUTE(attr) __has_cpp_attribute(attr)
+#else
+#define REALM_HAS_CCP_ATTRIBUTE(attr) 0
+#endif
+
+#if REALM_HAS_CCP_ATTRIBUTE(clang::fallthrough)
+#define REALM_FALLTHROUGH [[clang::fallthrough]]
+#else
+#define REALM_FALLTHROUGH
+#endif
+
+Results::Results(SharedRealm r, Query q, SortOrder s)
+: m_realm(std::move(r))
+, m_query(std::move(q))
+, m_table(m_query.get_table().get())
+, m_sort(std::move(s))
+, m_mode(Mode::Query)
 {
-    setSort(std::move(s));
+}
+
+Results::Results(SharedRealm r, Table& table)
+: m_realm(std::move(r))
+, m_table(&table)
+, m_mode(Mode::Table)
+{
+}
+
+void Results::validate_read() const
+{
+    if (m_realm)
+        m_realm->verify_thread();
+    if (m_table && !m_table->is_attached())
+        throw InvalidatedException();
+}
+
+void Results::validate_write() const
+{
+    validate_read();
+    if (!m_realm || !m_realm->is_in_transaction())
+        throw InvalidTransactionException("Must be in a write transaction");
 }
 
 size_t Results::size()
 {
-    verify_attached();
+    validate_read();
-    return table_view.size();
+    switch (m_mode) {
-}
+        case Mode::Empty: return 0;
-
+        case Mode::Table: return m_table->size();
-void Results::setSort(SortOrder s)
+        case Mode::Query: return m_query.count();
-{
+        case Mode::TableView:
-    sort_order = std::make_unique<SortOrder>(std::move(s));
+            update_tableview();
-    table_view.sort(sort_order->columnIndices, sort_order->ascending);
+            return m_table_view.size();
-}
-
-Row Results::get(std::size_t row_ndx)
-{
-    verify_attached();
-    if (row_ndx >= table_view.size()) {
-        throw std::out_of_range(std::string("Index ") + std::to_string(row_ndx) + " is outside of range 0..." +
-                               std::to_string(table_view.size()) + ".");
     }
-    return table_view.get(row_ndx);
+    REALM_UNREACHABLE();
 }
 
-void Results::verify_attached()
+RowExpr Results::get(size_t row_ndx)
 {
-    if (!table_view.is_attached()) {
+    validate_read();
-        throw std::runtime_error("Tableview is not attached");
+    switch (m_mode) {
+        case Mode::Empty: break;
+        case Mode::Table:
+            if (row_ndx < m_table->size())
+                return m_table->get(row_ndx);
+            break;
+        case Mode::Query:
+        case Mode::TableView:
+            update_tableview();
+            if (row_ndx < m_table_view.size())
+                return m_table_view.get(row_ndx);
+            break;
     }
-    table_view.sync_if_needed();
+
+    throw OutOfBoundsIndexException{row_ndx, size()};
+}
+
+util::Optional<RowExpr> Results::first()
+{
+    validate_read();
+    switch (m_mode) {
+        case Mode::Empty:
+            return none;
+        case Mode::Table:
+            return m_table->size() == 0 ? util::none : util::make_optional(m_table->front());
+        case Mode::Query:
+            update_tableview();
+            REALM_FALLTHROUGH;
+        case Mode::TableView:
+            return m_table_view.size() == 0 ? util::none : util::make_optional(m_table_view.front());
+    }
+    REALM_UNREACHABLE();
+}
+
+util::Optional<RowExpr> Results::last()
+{
+    validate_read();
+    switch (m_mode) {
+        case Mode::Empty:
+            return none;
+        case Mode::Table:
+            return m_table->size() == 0 ? util::none : util::make_optional(m_table->back());
+        case Mode::Query:
+            update_tableview();
+            REALM_FALLTHROUGH;
+        case Mode::TableView:
+            return m_table_view.size() == 0 ? util::none : util::make_optional(m_table_view.back());
+    }
+    REALM_UNREACHABLE();
+}
+
+void Results::update_tableview()
+{
+    validate_read();
+    switch (m_mode) {
+        case Mode::Empty:
+        case Mode::Table:
+            return;
+        case Mode::Query:
+            m_table_view = m_query.find_all();
+            if (m_sort) {
+                m_table_view.sort(m_sort.columnIndices, m_sort.ascending);
+            }
+            m_mode = Mode::TableView;
+            break;
+        case Mode::TableView:
+            m_table_view.sync_if_needed();
+            break;
+    }
+}
+
+size_t Results::index_of(Row const& row)
+{
+    validate_read();
+    if (!row) {
+        throw DetatchedAccessorException{};
+    }
+    if (m_table && row.get_table() != m_table) {
+        throw IncorrectTableException{
+            ObjectStore::object_type_for_table_name(m_table->get_name()),
+            ObjectStore::object_type_for_table_name(row.get_table()->get_name())};
+    }
+    return index_of(row.get_index());
+}
+
+size_t Results::index_of(size_t row_ndx)
+{
+    validate_read();
+    switch (m_mode) {
+        case Mode::Empty:
+            return not_found;
+        case Mode::Table:
+            return row_ndx;
+        case Mode::Query:
+            if (!m_sort)
+                return m_query.count(row_ndx, row_ndx + 1) ? m_query.count(0, row_ndx) : not_found;
+            REALM_FALLTHROUGH;
+        case Mode::TableView:
+            update_tableview();
+            return m_table_view.find_by_source_ndx(row_ndx);
+    }
+    REALM_UNREACHABLE();
+}
+
+template<typename Int, typename Float, typename Double, typename DateTime>
+util::Optional<Mixed> Results::aggregate(size_t column, bool return_none_for_empty,
+                                         Int agg_int, Float agg_float,
+                                         Double agg_double, DateTime agg_datetime)
+{
+    validate_read();
+    if (!m_table)
+        return none;
+    if (column > m_table->get_column_count())
+        throw OutOfBoundsIndexException{column, m_table->get_column_count()};
+
+    auto do_agg = [&](auto const& getter) -> util::Optional<Mixed> {
+        switch (m_mode) {
+            case Mode::Empty:
+                return none;
+            case Mode::Table:
+                if (return_none_for_empty && m_table->size() == 0)
+                    return none;
+                return util::Optional<Mixed>(getter(*m_table));
+            case Mode::Query:
+            case Mode::TableView:
+                this->update_tableview();
+                if (return_none_for_empty && m_table_view.size() == 0)
+                    return none;
+                return util::Optional<Mixed>(getter(m_table_view));
+        }
+        REALM_UNREACHABLE();
+    };
+
+    switch (m_table->get_column_type(column))
+    {
+        case type_DateTime: return do_agg(agg_datetime);
+        case type_Double: return do_agg(agg_double);
+        case type_Float: return do_agg(agg_float);
+        case type_Int: return do_agg(agg_int);
+        default:
+            throw UnsupportedColumnTypeException{column, m_table};
+    }
+}
+
+util::Optional<Mixed> Results::max(size_t column)
+{
+    return aggregate(column, true,
+                     [=](auto const& table) { return table.maximum_int(column); },
+                     [=](auto const& table) { return table.maximum_float(column); },
+                     [=](auto const& table) { return table.maximum_double(column); },
+                     [=](auto const& table) { return table.maximum_datetime(column); });
+}
+
+util::Optional<Mixed> Results::min(size_t column)
+{
+    return aggregate(column, true,
+                     [=](auto const& table) { return table.minimum_int(column); },
+                     [=](auto const& table) { return table.minimum_float(column); },
+                     [=](auto const& table) { return table.minimum_double(column); },
+                     [=](auto const& table) { return table.minimum_datetime(column); });
+}
+
+util::Optional<Mixed> Results::sum(size_t column)
+{
+    return aggregate(column, false,
+                     [=](auto const& table) { return table.sum_int(column); },
+                     [=](auto const& table) { return table.sum_float(column); },
+                     [=](auto const& table) { return table.sum_double(column); },
+                     [=](auto const&) -> util::None { throw UnsupportedColumnTypeException{column, m_table}; });
+}
+
+util::Optional<Mixed> Results::average(size_t column)
+{
+    return aggregate(column, true,
+                     [=](auto const& table) { return table.average_int(column); },
+                     [=](auto const& table) { return table.average_float(column); },
+                     [=](auto const& table) { return table.average_double(column); },
+                     [=](auto const&) -> util::None { throw UnsupportedColumnTypeException{column, m_table}; });
+}
+
+void Results::clear()
+{
+    switch (m_mode) {
+        case Mode::Empty:
+            return;
+        case Mode::Table:
+            validate_write();
+            m_table->clear();
+            break;
+        case Mode::Query:
+            // Not using Query:remove() because building the tableview and
+            // clearing it is actually significantly faster
+        case Mode::TableView:
+            validate_write();
+            update_tableview();
+            m_table_view.clear();
+            break;
+    }
+}
+
+Query Results::get_query() const
+{
+    validate_read();
+    switch (m_mode) {
+        case Mode::Empty:
+        case Mode::Query:
+        case Mode::TableView:
+            return m_query;
+        case Mode::Table:
+            return m_table->where();
+    }
+    REALM_UNREACHABLE();
+}
+
+TableView Results::get_tableview()
+{
+    validate_read();
+    switch (m_mode) {
+        case Mode::Empty:
+            return {};
+        case Mode::Query:
+        case Mode::TableView:
+            update_tableview();
+            return m_table_view;
+        case Mode::Table:
+            return m_table->where().find_all();
+    }
+    REALM_UNREACHABLE();
+}
+
+StringData Results::get_object_type() const noexcept
+{
+    return ObjectStore::object_type_for_table_name(m_table->get_name());
+}
+
+Results Results::sort(realm::SortOrder&& sort) const
+{
+    return Results(m_realm, get_query(), std::move(sort));
+}
+
+Results Results::filter(Query&& q) const
+{
+    return Results(m_realm, get_query().and_query(std::move(q)), get_sort());
+}
+
+Results::UnsupportedColumnTypeException::UnsupportedColumnTypeException(size_t column, const Table* table) {
+    column_index = column;
+    column_name = table->get_column_name(column);
+    column_type = table->get_column_type(column);
 }

results.hpp

@@ -1,39 +1,168 @@
-/* Copyright 2015 Realm Inc - All Rights Reserved
+////////////////////////////////////////////////////////////////////////////
- * Proprietary and Confidential
+//
- */
+// Copyright 2015 Realm Inc.
+//
+// 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.
+//
+////////////////////////////////////////////////////////////////////////////
 
 #ifndef REALM_RESULTS_HPP
 #define REALM_RESULTS_HPP
 
-#import "shared_realm.hpp"
+#include "shared_realm.hpp"
-#import <realm/table_view.hpp>
+
+#include <realm/table_view.hpp>
+#include <realm/table.hpp>
+#include <realm/util/optional.hpp>
 
 namespace realm {
-    struct SortOrder {
+template<typename T> class BasicRowExpr;
-        std::vector<size_t> columnIndices;
+using RowExpr = BasicRowExpr<Table>;
-        std::vector<bool> ascending;
+class Mixed;
 
-        explicit operator bool() const {
+struct SortOrder {
-            return !columnIndices.empty();
+    std::vector<size_t> columnIndices;
-        }
+    std::vector<bool> ascending;
+
+    explicit operator bool() const
+    {
+        return !columnIndices.empty();
+    }
+};
+
+class Results {
+public:
+    // Results can be either be backed by nothing, a thin wrapper around a table,
+    // or a wrapper around a query and a sort order which creates and updates
+    // the tableview as needed
+    Results() = default;
+    Results(SharedRealm r, Table& table);
+    Results(SharedRealm r, Query q, SortOrder s = {});
+
+    // Results is copyable and moveable
+    Results(Results const&) = default;
+    Results(Results&&) = default;
+    Results& operator=(Results const&) = default;
+    Results& operator=(Results&&) = default;
+
+    // Get a query which will match the same rows as is contained in this Results
+    // Returned query will not be valid if the current mode is Empty
+    Query get_query() const;
+
+    // Get the currently applied sort order for this Results
+    SortOrder const& get_sort() const noexcept { return m_sort; }
+
+    // Get a tableview containing the same rows as this Results
+    TableView get_tableview();
+
+    // Get the object type which will be returned by get()
+    StringData get_object_type() const noexcept;
+
+    // Get the size of this results
+    // Can be either O(1) or O(N) depending on the state of things
+    size_t size();
+
+    // Get the row accessor for the given index
+    // Throws OutOfBoundsIndexException if index >= size()
+    RowExpr get(size_t index);
+
+    // Get a row accessor for the first/last row, or none if the results are empty
+    // More efficient than calling size()+get()
+    util::Optional<RowExpr> first();
+    util::Optional<RowExpr> last();
+
+    // Get the first index of the given row in this results, or not_found
+    // Throws DetachedAccessorException if row is not attached
+    // Throws IncorrectTableException if row belongs to a different table
+    size_t index_of(size_t row_ndx);
+    size_t index_of(Row const& row);
+
+    // Delete all of the rows in this Results from the Realm
+    // size() will always be zero afterwards
+    // Throws InvalidTransactionException if not in a write transaction
+    void clear();
+
+    // Create a new Results by further filtering or sorting this Results
+    Results filter(Query&& q) const;
+    Results sort(SortOrder&& sort) const;
+
+    // Get the min/max/average/sum of the given column
+    // All but sum() returns none when there are zero matching rows
+    // sum() returns 0, except for when it returns none
+    // Throws UnsupportedColumnTypeException for sum/average on datetime or non-numeric column
+    // Throws OutOfBoundsIndexException for an out-of-bounds column
+    util::Optional<Mixed> max(size_t column);
+    util::Optional<Mixed> min(size_t column);
+    util::Optional<Mixed> average(size_t column);
+    util::Optional<Mixed> sum(size_t column);
+
+    enum class Mode {
+        Empty, // Backed by nothing (for missing tables)
+        Table, // Backed directly by a Table
+        Query, // Backed by a query that has not yet been turned into a TableView
+        TableView // Backed by a TableView created from a Query
+    };
+    // Get the currrent mode of the Results
+    // Ideally this would not be public but it's needed for some KVO stuff
+    Mode get_mode() const { return m_mode; }
+
+    // The Results object has been invalidated (due to the Realm being invalidated)
+    // All non-noexcept functions can throw this
+    struct InvalidatedException {};
+
+    // The input index parameter was out of bounds
+    struct OutOfBoundsIndexException {
+        size_t requested;
+        size_t valid_count;
     };
 
-    static SortOrder s_defaultSort = {{}, {}};
+    // The input Row object is not attached
+    struct DetatchedAccessorException { };
 
-    struct Results {
+    // The input Row object belongs to a different table
-        Results(SharedRealm &r, ObjectSchema &o, Query q, SortOrder s = s_defaultSort);
+    struct IncorrectTableException {
-        size_t size();
+        StringData expected;
-        Row get(std::size_t row_ndx);
+        StringData actual;
-        void verify_attached();
-
-        SharedRealm realm;
-        ObjectSchema &object_schema;
-        Query backing_query;
-        TableView table_view;
-        std::unique_ptr<SortOrder> sort_order;
-
-        void setSort(SortOrder s);
     };
+
+    // The requested aggregate operation is not supported for the column type
+    struct UnsupportedColumnTypeException {
+        size_t column_index;
+        StringData column_name;
+        DataType column_type;
+
+        UnsupportedColumnTypeException(size_t column, const Table* table);
+    };
+
+private:
+    SharedRealm m_realm;
+    Query m_query;
+    TableView m_table_view;
+    Table* m_table = nullptr;
+    SortOrder m_sort;
+
+    Mode m_mode = Mode::Empty;
+
+    void validate_read() const;
+    void validate_write() const;
+
+    void update_tableview();
+
+    template<typename Int, typename Float, typename Double, typename DateTime>
+    util::Optional<Mixed> aggregate(size_t column, bool return_none_for_empty,
+                                    Int agg_int, Float agg_float,
+                                    Double agg_double, DateTime agg_datetime);
+};
 }
 
 #endif /* REALM_RESULTS_HPP */

shared_realm.cpp

@@ -47,6 +47,8 @@ Realm::Config::Config(const Config& c)
     }
 }
 
+Realm::Config::Config() = default;
+Realm::Config::Config(Config&&) = default;
 Realm::Config::~Config() = default;
 
 Realm::Config& Realm::Config::operator=(realm::Realm::Config const& c)
@@ -237,7 +239,14 @@ static void check_read_write(Realm *realm)
 void Realm::verify_thread() const
 {
     if (m_thread_id != std::this_thread::get_id()) {
-        throw IncorrectThreadException("Realm accessed from incorrect thread.");
+        throw IncorrectThreadException();
+    }
+}
+
+void Realm::verify_in_write() const
+{
+    if (!is_in_transaction()) {
+        throw InvalidTransactionException("Cannot modify persisted objects outside of a write transaction.");
     }
 }
 

shared_realm.hpp

@@ -19,7 +19,6 @@
 #ifndef REALM_REALM_HPP
 #define REALM_REALM_HPP
 
-#include <map>
 #include <memory>
 #include <thread>
 #include <vector>
@@ -56,8 +55,8 @@ namespace realm {
 
             MigrationFunction migration_function;
 
-            Config() = default;
+            Config();
-            Config(Config&&) = default;
+            Config(Config&&);
             Config(const Config& c);
             ~Config();
 
@@ -100,6 +99,7 @@ namespace realm {
 
         std::thread::id thread_id() const { return m_thread_id; }
         void verify_thread() const;
+        void verify_in_write() const;
 
         // Close this Realm and remove it from the cache. Continuing to use a
         // Realm after closing it will produce undefined behavior.
@@ -145,11 +145,9 @@ namespace realm {
         std::mutex m_mutex;
     };
 
-    class RealmFileException : public std::runtime_error
+    class RealmFileException : public std::runtime_error {
-    {
+    public:
-      public:
+        enum class Kind {
-        enum class Kind
-        {
             /** Thrown for any I/O related exception scenarios when a realm is opened. */
             AccessError,
             /** Thrown if the user does not have permission to open or create
@@ -169,32 +167,28 @@ namespace realm {
         Kind kind() const { return m_kind; }
         const std::string& path() const { return m_path; }
         
-      private:
+    private:
         Kind m_kind;
         std::string m_path;
     };
 
-    class MismatchedConfigException : public std::runtime_error
+    class MismatchedConfigException : public std::runtime_error {
-    {
+    public:
-      public:
         MismatchedConfigException(std::string message) : std::runtime_error(message) {}
     };
 
-    class InvalidTransactionException : public std::runtime_error
+    class InvalidTransactionException : public std::runtime_error {
-    {
+    public:
-      public:
         InvalidTransactionException(std::string message) : std::runtime_error(message) {}
     };
 
-    class IncorrectThreadException : public std::runtime_error
+    class IncorrectThreadException : public std::runtime_error {
-    {
+    public:
-      public:
+        IncorrectThreadException() : std::runtime_error("Realm accessed from incorrect thread.") {}
-        IncorrectThreadException(std::string message) : std::runtime_error(message) {}
     };
 
-    class UnitializedRealmException : public std::runtime_error
+    class UnitializedRealmException : public std::runtime_error {
-    {
+    public:
-      public:
         UnitializedRealmException(std::string message) : std::runtime_error(message) {}
     };
 }