diff --git a/src/impl/transact_log_handler.cpp b/src/impl/transact_log_handler.cpp index 031485e4..299dcaad 100644 --- a/src/impl/transact_log_handler.cpp +++ b/src/impl/transact_log_handler.cpp @@ -24,8 +24,122 @@ #include #include -namespace realm { -class TransactLogHandler { +using namespace realm; + +namespace { +// A transaction log handler that just validates that all operations made are +// ones supported by the object store +class TransactLogValidator { + // Index of currently selected table + size_t m_current_table = 0; + + // Tables which were created during the transaction being processed, which + // can have columns inserted without a schema version bump + std::vector m_new_tables; + + REALM_NORETURN + REALM_NOINLINE + void schema_error() + { + throw std::runtime_error("Schema mismatch detected: another process has modified the Realm file's schema in an incompatible way"); + } + + // Throw an exception if the currently modified table already existed before + // the current set of modifications + bool schema_error_unless_new_table() + { + if (std::find(begin(m_new_tables), end(m_new_tables), m_current_table) == end(m_new_tables)) { + schema_error(); + } + return true; + } + +protected: + size_t current_table() const noexcept { return m_current_table; } + +public: + // Schema changes which don't involve a change in the schema version are + // allowed + bool add_search_index(size_t) { return true; } + bool remove_search_index(size_t) { return true; } + + // Creating entirely new tables without a schema version bump is allowed, so + // we need to track if new columns are being added to a new table or an + // existing one + bool insert_group_level_table(size_t table_ndx, size_t, StringData) + { + // Shift any previously added tables after the new one + for (auto& table : m_new_tables) { + if (table >= table_ndx) + ++table; + } + m_new_tables.push_back(table_ndx); + return true; + } + bool insert_column(size_t, DataType, StringData, bool) { return schema_error_unless_new_table(); } + bool insert_link_column(size_t, DataType, StringData, size_t, size_t) { return schema_error_unless_new_table(); } + bool add_primary_key(size_t) { return schema_error_unless_new_table(); } + bool set_link_type(size_t, LinkType) { return schema_error_unless_new_table(); } + + // Removing or renaming things while a Realm is open is never supported + bool erase_group_level_table(size_t, size_t) { schema_error(); } + bool rename_group_level_table(size_t, StringData) { schema_error(); } + bool erase_column(size_t) { schema_error(); } + bool erase_link_column(size_t, size_t, size_t) { schema_error(); } + bool rename_column(size_t, StringData) { schema_error(); } + bool remove_primary_key() { schema_error(); } + bool move_column(size_t, size_t) { schema_error(); } + bool move_group_level_table(size_t, size_t) { schema_error(); } + + bool select_descriptor(int levels, const size_t*) + { + // subtables not supported + return levels == 0; + } + + bool select_table(size_t group_level_ndx, int, const size_t*) noexcept + { + m_current_table = group_level_ndx; + return true; + } + + bool select_link_list(size_t, size_t, size_t) { return true; } + + // Non-schema changes are all allowed + void parse_complete() { } + bool insert_empty_rows(size_t, size_t, size_t, bool) { return true; } + bool erase_rows(size_t, size_t, size_t, bool) { return true; } + bool swap_rows(size_t, size_t) { return true; } + bool clear_table() noexcept { return true; } + bool link_list_set(size_t, size_t) { return true; } + bool link_list_insert(size_t, size_t) { return true; } + bool link_list_erase(size_t) { return true; } + bool link_list_nullify(size_t) { return true; } + bool link_list_clear(size_t) { return true; } + bool link_list_move(size_t, size_t) { return true; } + bool link_list_swap(size_t, size_t) { return true; } + bool set_int(size_t, size_t, int_fast64_t) { return true; } + bool set_bool(size_t, size_t, bool) { return true; } + bool set_float(size_t, size_t, float) { return true; } + bool set_double(size_t, size_t, double) { return true; } + bool set_string(size_t, size_t, StringData) { return true; } + bool set_binary(size_t, size_t, BinaryData) { return true; } + bool set_date_time(size_t, size_t, DateTime) { return true; } + bool set_table(size_t, size_t) { return true; } + bool set_mixed(size_t, size_t, const Mixed&) { return true; } + bool set_link(size_t, size_t, size_t, size_t) { return true; } + bool set_null(size_t, size_t) { return true; } + bool nullify_link(size_t, size_t, size_t) { return true; } + bool insert_substring(size_t, size_t, size_t, StringData) { return true; } + bool erase_substring(size_t, size_t, size_t, size_t) { return true; } + bool optimize_table() { return true; } + bool set_int_unique(size_t, size_t, int_fast64_t) { return true; } + bool set_string_unique(size_t, size_t, StringData) { return true; } +}; + +// Extends TransactLogValidator to also track changes and report it to the +// binding context if any properties are being observed +class TransactLogObserver : public TransactLogValidator { using ColumnInfo = BindingContext::ColumnInfo; using ObserverState = BindingContext::ObserverState; @@ -34,10 +148,8 @@ class TransactLogHandler { // Userdata pointers for rows which have been deleted std::vector invalidated; // Delegate to send change information to - BindingContext* m_binding_context; + BindingContext* m_context; - // Index of currently selected table - size_t m_current_table = 0; // Change information for the currently selected LinkList, if any ColumnInfo* m_active_linklist = nullptr; @@ -69,8 +181,8 @@ class TransactLogHandler { // Mark the given row/col as needing notifications sent bool mark_dirty(size_t row_ndx, size_t col_ndx) { - auto it = lower_bound(begin(m_observers), end(m_observers), ObserverState{m_current_table, row_ndx, nullptr}); - if (it != end(m_observers) && it->table_ndx == m_current_table && it->row_ndx == row_ndx) { + auto it = lower_bound(begin(m_observers), end(m_observers), ObserverState{current_table(), row_ndx, nullptr}); + if (it != end(m_observers) && it->table_ndx == current_table() && it->row_ndx == row_ndx) { get_change(*it, col_ndx).changed = true; } return true; @@ -84,86 +196,57 @@ class TransactLogHandler { m_observers.erase(m_observers.begin() + (o - &m_observers[0])); } - REALM_NORETURN - REALM_NOINLINE - void schema_error() - { - throw std::runtime_error("Schema mismatch detected: another process has modified the Realm file's schema in an incompatible way"); - } - - bool schema_error_unless_new_table() - { - if (std::find(begin(m_new_tables), end(m_new_tables), m_current_table) == end(m_new_tables)) { - schema_error(); - } - return true; - } - public: template - TransactLogHandler(BindingContext* binding_context, SharedGroup& sg, Func&& func) - : m_binding_context(binding_context) + TransactLogObserver(BindingContext* context, SharedGroup& sg, Func&& func, bool validate_schema_changes) + : m_context(context) { - if (!binding_context) { - func(); + if (!context) { + if (validate_schema_changes) { + // The handler functions are non-virtual, so the parent class's + // versions are called if we don't need to track changes to observed + // objects + func(static_cast(*this)); + } + else { + func(); + } return; } - m_observers = binding_context->get_observed_rows(); + m_observers = context->get_observed_rows(); if (m_observers.empty()) { auto old_version = sg.get_version_of_current_transaction(); - func(); + if (validate_schema_changes) { + func(static_cast(*this)); + } + else { + func(); + } if (old_version != sg.get_version_of_current_transaction()) { - binding_context->did_change({}, {}); + context->did_change({}, {}); } return; } func(*this); - binding_context->did_change(m_observers, invalidated); + context->did_change(m_observers, invalidated); } // Called at the end of the transaction log immediately before the version // is advanced void parse_complete() { - m_binding_context->will_change(m_observers, invalidated); + m_context->will_change(m_observers, invalidated); } - // Schema changes which don't involve a change in the schema version are - // allowed - bool add_search_index(size_t) { return true; } - bool remove_search_index(size_t) { return true; } - - // Creating entirely new tables without a schema version bump is allowed, so - // we need to track if new columns are being added to a new table or an - // existing one - bool insert_group_level_table(size_t table_ndx, size_t, StringData) + bool insert_group_level_table(size_t table_ndx, size_t prior_size, StringData name) { for (auto& observer : m_observers) { if (observer.table_ndx >= table_ndx) ++observer.table_ndx; } - m_new_tables.push_back(table_ndx); - return true; - } - - bool insert_column(size_t, DataType, StringData, bool) { return schema_error_unless_new_table(); } - bool insert_link_column(size_t, DataType, StringData, size_t, size_t) { return schema_error_unless_new_table(); } - bool add_primary_key(size_t) { return schema_error_unless_new_table(); } - bool set_link_type(size_t, LinkType) { return schema_error_unless_new_table(); } - - // Schema changes which are never allowed while a file is open - bool erase_group_level_table(size_t, size_t) { schema_error(); } - bool rename_group_level_table(size_t, StringData) { schema_error(); } - bool erase_column(size_t) { schema_error(); } - bool erase_link_column(size_t, size_t, size_t) { schema_error(); } - bool rename_column(size_t, StringData) { schema_error(); } - bool remove_primary_key() { schema_error(); } - - bool select_table(size_t group_level_ndx, int, const size_t*) noexcept - { - m_current_table = group_level_ndx; + TransactLogValidator::insert_group_level_table(table_ndx, prior_size, name); return true; } @@ -177,7 +260,7 @@ public: { for (size_t i = 0; i < m_observers.size(); ++i) { auto& o = m_observers[i]; - if (o.table_ndx == m_current_table) { + if (o.table_ndx == current_table()) { if (o.row_ndx == row_ndx) { invalidate(&o); --i; @@ -197,7 +280,7 @@ public: { for (size_t i = 0; i < m_observers.size(); ) { auto& o = m_observers[i]; - if (o.table_ndx == m_current_table) { + if (o.table_ndx == current_table()) { invalidate(&o); } else { @@ -211,7 +294,7 @@ public: { m_active_linklist = nullptr; for (auto& o : m_observers) { - if (o.table_ndx == m_current_table && o.row_ndx == row) { + if (o.table_ndx == current_table() && o.row_ndx == row) { m_active_linklist = &get_change(o, col); break; } @@ -342,47 +425,41 @@ public: bool set_string_unique(size_t col, size_t row, StringData) { return mark_dirty(row, col); } bool insert_substring(size_t col, size_t row, size_t, StringData) { return mark_dirty(row, col); } bool erase_substring(size_t col, size_t row, size_t, size_t) { return mark_dirty(row, col); } - - // Doesn't change any data - bool optimize_table() { return true; } - - // Used for subtables, which we currently don't support - bool select_descriptor(int, const size_t*) { return false; } - - // Not implemented - bool swap_rows(size_t, size_t) { return false; } - bool move_column(size_t, size_t) { return false; } - bool move_group_level_table(size_t, size_t) { return false; } }; } // anonymous namespace namespace realm { namespace _impl { namespace transaction { -void advance(SharedGroup& sg, ClientHistory& history, BindingContext* binding_context) { - TransactLogHandler(binding_context, sg, [&](auto&&... args) { +void advance(SharedGroup& sg, ClientHistory& history, BindingContext* context) +{ + TransactLogObserver(context, sg, [&](auto&&... args) { LangBindHelper::advance_read(sg, history, std::move(args)...); - }); + }, true); } -void begin(SharedGroup& sg, ClientHistory& history, BindingContext* binding_context) { - TransactLogHandler(binding_context, sg, [&](auto&&... args) { +void begin(SharedGroup& sg, ClientHistory& history, BindingContext* context, + bool validate_schema_changes) +{ + TransactLogObserver(context, sg, [&](auto&&... args) { LangBindHelper::promote_to_write(sg, history, std::move(args)...); - }); + }, validate_schema_changes); } -void commit(SharedGroup& sg, ClientHistory&, BindingContext* binding_context) { +void commit(SharedGroup& sg, ClientHistory&, BindingContext* context) +{ LangBindHelper::commit_and_continue_as_read(sg); - if (binding_context) { - binding_context->did_change({}, {}); + if (context) { + context->did_change({}, {}); } } -void cancel(SharedGroup& sg, ClientHistory& history, BindingContext* binding_context) { - TransactLogHandler(binding_context, sg, [&](auto&&... args) { +void cancel(SharedGroup& sg, ClientHistory& history, BindingContext* context) +{ + TransactLogObserver(context, sg, [&](auto&&... args) { LangBindHelper::rollback_and_continue_as_read(sg, history, std::move(args)...); - }); + }, false); } } // namespace transaction diff --git a/src/impl/transact_log_handler.hpp b/src/impl/transact_log_handler.hpp index 40ddf3f6..f5d3d58a 100644 --- a/src/impl/transact_log_handler.hpp +++ b/src/impl/transact_log_handler.hpp @@ -33,7 +33,8 @@ void advance(SharedGroup& sg, ClientHistory& history, BindingContext* binding_co // Begin a write transaction // If the read transaction version is not up to date, will first advance to the // most recent read transaction and sent notifications to delegate -void begin(SharedGroup& sg, ClientHistory& history, BindingContext* binding_context); +void begin(SharedGroup& sg, ClientHistory& history, BindingContext* binding_context, + bool validate_schema_changes=true); // Commit a write transaction void commit(SharedGroup& sg, ClientHistory& history, BindingContext* binding_context); diff --git a/src/shared_realm.cpp b/src/shared_realm.cpp index 30e8f928..5c17eb63 100644 --- a/src/shared_realm.cpp +++ b/src/shared_realm.cpp @@ -222,7 +222,11 @@ void Realm::update_schema(std::unique_ptr schema, uint64_t version) return; } - begin_transaction(); + read_group(); + transaction::begin(*m_shared_group, *m_history, m_binding_context.get(), + /* error on schema changes */ false); + m_in_transaction = true; + struct WriteTransactionGuard { Realm& realm; ~WriteTransactionGuard() {