Implement better handling of database errors & database disk space issues (Issue #77) (#80)

* Implement better handling of database exit scenarios when there is zero disk space left on drive where the items database resides (Issue #77)
* Implement better handling of incorrect database permissions
* Implement better handling of different database versions to automatically re-create tables if version mis-match (RHBZ #1598934)

src/itemdb.d

@@ -2,7 +2,9 @@ import std.datetime;
 import std.exception;
 import std.path;
 import std.string;
+import core.stdc.stdlib;
 import sqlite;
+static import log;
 
 enum ItemType {
 	file,
@@ -29,7 +31,7 @@ struct Item {
 final class ItemDatabase
 {
 	// increment this for every change in the db schema
-	immutable int itemDatabaseVersion = 6;
+	immutable int itemDatabaseVersion = 7;
 
 	Database db;
 	Statement insertItemStmt;
@@ -41,33 +43,21 @@ final class ItemDatabase
 	this(const(char)[] filename)
 	{
 		db = Database(filename);
-		if (db.getVersion() == 0) {
-			db.exec("CREATE TABLE item (
-				driveId          TEXT NOT NULL,
-				id               TEXT NOT NULL,
-				name             TEXT NOT NULL,
-				type             TEXT NOT NULL,
-				eTag             TEXT,
-				cTag             TEXT,
-				mtime            TEXT NOT NULL,
-				parentId         TEXT,
-				crc32Hash        TEXT,
-				sha1Hash         TEXT,
-				quickXorHash     TEXT,
-				remoteDriveId    TEXT,
-				remoteId         TEXT,
-				deltaLink        TEXT,
-				PRIMARY KEY (driveId, id),
-				FOREIGN KEY (driveId, parentId)
-				REFERENCES item (driveId, id)
-				ON DELETE CASCADE
-				ON UPDATE RESTRICT
-			)");
-			db.exec("CREATE INDEX name_idx ON item (name)");
-			db.exec("CREATE INDEX remote_idx ON item (remoteDriveId, remoteId)");
-			db.setVersion(itemDatabaseVersion);
+		int dbVersion;
+		try {
+			dbVersion = db.getVersion();
+		} catch (SqliteException e) {
+			// An error was generated - what was the error?
+			log.error("\nAn internal database error occurred: " ~ e.msg ~ "\n");
+			exit(-1);
+		}
+		
+		if (dbVersion == 0) {
+			createTable();
 		} else if (db.getVersion() != itemDatabaseVersion) {
-			throw new Exception("The item database is incompatible, please resync manually");
+			log.log("The item database is incompatible, re-creating database table structures");
+			db.exec("DROP TABLE item");
+			createTable();
 		}
 		db.exec("PRAGMA foreign_keys = ON");
 		db.exec("PRAGMA recursive_triggers = ON");
@@ -91,6 +81,34 @@ final class ItemDatabase
 		deleteItemByIdStmt = db.prepare("DELETE FROM item WHERE driveId = ? AND id = ?");
 	}
 
+	void createTable()
+	{
+		db.exec("CREATE TABLE item (
+				driveId          TEXT NOT NULL,
+				id               TEXT NOT NULL,
+				name             TEXT NOT NULL,
+				type             TEXT NOT NULL,
+				eTag             TEXT,
+				cTag             TEXT,
+				mtime            TEXT NOT NULL,
+				parentId         TEXT,
+				crc32Hash        TEXT,
+				sha1Hash         TEXT,
+				quickXorHash     TEXT,
+				remoteDriveId    TEXT,
+				remoteId         TEXT,
+				deltaLink        TEXT,
+				PRIMARY KEY (driveId, id),
+				FOREIGN KEY (driveId, parentId)
+				REFERENCES item (driveId, id)
+				ON DELETE CASCADE
+				ON UPDATE RESTRICT
+			)");
+		db.exec("CREATE INDEX name_idx ON item (name)");
+		db.exec("CREATE INDEX remote_idx ON item (remoteDriveId, remoteId)");
+		db.setVersion(itemDatabaseVersion);
+	}
+	
 	void insert(const ref Item item)
 	{
 		bindItem(item, insertItemStmt);

src/sqlite.d

@@ -2,6 +2,8 @@ module sqlite;
 import std.stdio;
 import etc.c.sqlite3;
 import std.string: fromStringz, toStringz;
+import core.stdc.stdlib;
+static import log;
 
 extern (C) immutable(char)* sqlite3_errstr(int); // missing from the std library
 
@@ -48,9 +50,16 @@ struct Database
 	{
 		// https://www.sqlite.org/c3ref/open.html
 		int rc = sqlite3_open(toStringz(filename), &pDb);
-		if (rc != SQLITE_OK) {
+		if (rc == SQLITE_CANTOPEN) {
+			// Database cannot be opened
+			log.error("\nThe database cannot be opened. Please check the permissions of ~/.config/onedrive/items.sqlite3\n");
 			close();
-			throw new SqliteException(ifromStringz(sqlite3_errstr(rc)));
+			exit(-1);
+		}
+		if (rc != SQLITE_OK) {
+			log.error("\nA database access error occurred: " ~ getErrorMessage() ~ "\n");
+			close();
+			exit(-1);
 		}
 		sqlite3_extended_result_codes(pDb, 1); // always use extended result codes
 	}
@@ -60,7 +69,9 @@ struct Database
 		// https://www.sqlite.org/c3ref/exec.html
 		int rc = sqlite3_exec(pDb, toStringz(sql), null, null, null);
 		if (rc != SQLITE_OK) {
-			throw new SqliteException(ifromStringz(sqlite3_errmsg(pDb)));
+			log.error("\nA database execution error occurred: "~ getErrorMessage() ~ "\n");
+			close();
+			exit(-1);
 		}
 	}
 
@@ -79,6 +90,11 @@ struct Database
 		return userVersion;
 	}
 
+	string getErrorMessage()
+	{
+		return ifromStringz(sqlite3_errmsg(pDb));
+	}
+	
 	void setVersion(int userVersion)
 	{
 		import std.conv: to;
@@ -135,7 +151,7 @@ struct Statement
 			int rc = sqlite3_step(pStmt);
 			if (rc == SQLITE_BUSY) {
 				// Database is locked by another onedrive process
-				writeln("The database is currently locked by another process - cannot sync");
+				log.error("The database is currently locked by another process - cannot sync");
 				return;
 			}
 			if (rc == SQLITE_DONE) {
@@ -149,7 +165,9 @@ struct Statement
 					column = fromStringz(sqlite3_column_text(pStmt, i));
 				}
 			} else {
-				throw new SqliteException(ifromStringz(sqlite3_errmsg(sqlite3_db_handle(pStmt))));
+				string errorMessage = ifromStringz(sqlite3_errmsg(sqlite3_db_handle(pStmt)));
+				log.error("\nA database statement execution error occurred: "~ errorMessage ~ "\n");
+				exit(-1);
 			}
 		}
 	}