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Diffstat (limited to 'updater/sql/win/src/backup.h')
| -rwxr-xr-x | updater/sql/win/src/backup.h | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/updater/sql/win/src/backup.h b/updater/sql/win/src/backup.h new file mode 100755 index 0000000..b894aca --- /dev/null +++ b/updater/sql/win/src/backup.h @@ -0,0 +1,209 @@ +#ifndef NODE_SQLITE3_SRC_BACKUP_H +#define NODE_SQLITE3_SRC_BACKUP_H + +#include "database.h" + +#include <string> +#include <queue> +#include <set> + +#include <sqlite3.h> +#include <napi.h> + +using namespace Napi; + +namespace node_sqlite3 { + +/** + * + * A class for managing an sqlite3_backup object. For consistency + * with other node-sqlite3 classes, it maintains an internal queue + * of calls. + * + * Intended usage from node: + * + * var db = new sqlite3.Database('live.db'); + * var backup = db.backup('backup.db'); + * ... + * // in event loop, move backup forward when we have time. + * if (backup.idle) { backup.step(NPAGES); } + * if (backup.completed) { ... success ... } + * if (backup.failed) { ... sadness ... } + * // do other work in event loop - fine to modify live.db + * ... + * + * Here is how sqlite's backup api is exposed: + * + * - `sqlite3_backup_init`: This is implemented as + * `db.backup(filename, [callback])` or + * `db.backup(filename, destDbName, sourceDbName, filenameIsDest, [callback])`. + * - `sqlite3_backup_step`: `backup.step(pages, [callback])`. + * - `sqlite3_backup_finish`: `backup.finish([callback])`. + * - `sqlite3_backup_remaining`: `backup.remaining`. + * - `sqlite3_backup_pagecount`: `backup.pageCount`. + * + * There are the following read-only properties: + * + * - `backup.completed` is set to `true` when the backup + * succeeeds. + * - `backup.failed` is set to `true` when the backup + * has a fatal error. + * - `backup.idle` is set to `true` when no operation + * is currently in progress or queued for the backup. + * - `backup.remaining` is an integer with the remaining + * number of pages after the last call to `backup.step` + * (-1 if `step` not yet called). + * - `backup.pageCount` is an integer with the total number + * of pages measured during the last call to `backup.step` + * (-1 if `step` not yet called). + * + * There is the following writable property: + * + * - `backup.retryErrors`: an array of sqlite3 error codes + * that are treated as non-fatal - meaning, if they occur, + * backup.failed is not set, and the backup may continue. + * By default, this is `[sqlite3.BUSY, sqlite3.LOCKED]`. + * + * The `db.backup(filename, [callback])` shorthand is sufficient + * for making a backup of a database opened by node-sqlite3. If + * using attached or temporary databases, or moving data in the + * opposite direction, the more complete (but daunting) + * `db.backup(filename, destDbName, sourceDbName, filenameIsDest, [callback])` + * signature is provided. + * + * A backup will finish automatically when it succeeds or a fatal + * error occurs, meaning it is not necessary to call `db.finish()`. + * By default, SQLITE_LOCKED and SQLITE_BUSY errors are not + * treated as failures, and the backup will continue if they + * occur. The set of errors that are tolerated can be controlled + * by setting `backup.retryErrors`. To disable automatic + * finishing and stick strictly to sqlite's raw api, set + * `backup.retryErrors` to `[]`. In that case, it is necessary + * to call `backup.finish()`. + * + * In the same way as node-sqlite3 databases and statements, + * backup methods can be called safely without callbacks, due + * to an internal call queue. So for example this naive code + * will correctly back up a db, if there are no errors: + * + * var backup = db.backup('backup.db'); + * backup.step(-1); + * backup.finish(); + * + */ +class Backup : public Napi::ObjectWrap<Backup> { +public: + static Napi::Object Init(Napi::Env env, Napi::Object exports); + + struct Baton { + napi_async_work request = NULL; + Backup* backup; + Napi::FunctionReference callback; + + Baton(Backup* backup_, Napi::Function cb_) : backup(backup_) { + backup->Ref(); + callback.Reset(cb_, 1); + } + virtual ~Baton() { + if (request) napi_delete_async_work(backup->Env(), request); + backup->Unref(); + callback.Reset(); + } + }; + + struct InitializeBaton : Database::Baton { + Backup* backup; + std::string filename; + std::string sourceName; + std::string destName; + bool filenameIsDest; + InitializeBaton(Database* db_, Napi::Function cb_, Backup* backup_) : + Baton(db_, cb_), backup(backup_), filenameIsDest(true) { + backup->Ref(); + } + virtual ~InitializeBaton() override { + backup->Unref(); + if (!db->IsOpen() && db->IsLocked()) { + // The database handle was closed before the backup could be opened. + backup->FinishAll(); + } + } + }; + + struct StepBaton : Baton { + int pages; + std::set<int> retryErrorsSet; + StepBaton(Backup* backup_, Napi::Function cb_, int pages_) : + Baton(backup_, cb_), pages(pages_) {} + virtual ~StepBaton() override = default; + }; + + typedef void (*Work_Callback)(Baton* baton); + + struct Call { + Call(Work_Callback cb_, Baton* baton_) : callback(cb_), baton(baton_) {}; + Work_Callback callback; + Baton* baton; + }; + + Backup(const Napi::CallbackInfo& info); + + ~Backup() { + if (!finished) { + FinishAll(); + } + retryErrors.Reset(); + } + + WORK_DEFINITION(Step) + WORK_DEFINITION(Finish) + + Napi::Value IdleGetter(const Napi::CallbackInfo& info); + Napi::Value CompletedGetter(const Napi::CallbackInfo& info); + Napi::Value FailedGetter(const Napi::CallbackInfo& info); + Napi::Value PageCountGetter(const Napi::CallbackInfo& info); + Napi::Value RemainingGetter(const Napi::CallbackInfo& info); + Napi::Value FatalErrorGetter(const Napi::CallbackInfo& info); + Napi::Value RetryErrorGetter(const Napi::CallbackInfo& info); + + void FatalErrorSetter(const Napi::CallbackInfo& info, const Napi::Value& value); + void RetryErrorSetter(const Napi::CallbackInfo& info, const Napi::Value& value); + +protected: + static void Work_BeginInitialize(Database::Baton* baton); + static void Work_Initialize(napi_env env, void* data); + static void Work_AfterInitialize(napi_env env, napi_status status, void* data); + + void Schedule(Work_Callback callback, Baton* baton); + void Process(); + void CleanQueue(); + template <class T> static void Error(T* baton); + + void FinishAll(); + void FinishSqlite(); + void GetRetryErrors(std::set<int>& retryErrorsSet); + + Database* db; + + sqlite3_backup* _handle = NULL; + sqlite3* _otherDb = NULL; + sqlite3* _destDb = NULL; + + bool inited = false; + bool locked = true; + bool completed = false; + bool failed = false; + int remaining = -1; + int pageCount = -1; + bool finished = false; + + int status; + std::string message; + std::queue<std::unique_ptr<Call>> queue; + + Napi::Reference<Array> retryErrors; +}; + +} + +#endif |