feat(backend): add database SQL export/import with backup

- Enable rusqlite backup feature for SQL dump support
- Implement export_sql to generate SQLite-compatible SQL dumps
- Implement import_sql with automatic backup before import
- Add snapshot_to_memory to avoid long-held database locks
- Add backup rotation to retain latest 10 backups
- Support atomic import with rollback on failure

src-tauri/Cargo.toml

@@ -51,7 +51,7 @@ url = "2.5"
 auto-launch = "0.5"
 once_cell = "1.21.3"
 base64 = "0.22"
-rusqlite = { version = "0.31", features = ["bundled"] }
+rusqlite = { version = "0.31", features = ["bundled", "backup"] }
 indexmap = { version = "2", features = ["serde"] }
 
 [target.'cfg(any(target_os = "macos", target_os = "windows", target_os = "linux"))'.dependencies]

src-tauri/src/database.rs

@@ -4,11 +4,17 @@ use crate::error::AppError;
 use crate::prompt::Prompt;
 use crate::provider::{Provider, ProviderMeta};
 use crate::services::skill::{SkillRepo, SkillState};
+use chrono::Utc;
 use indexmap::IndexMap;
-use rusqlite::{params, Connection, Result};
+use rusqlite::backup::Backup;
+use rusqlite::types::ValueRef;
+use rusqlite::{params, Connection};
 use serde::Serialize;
 use std::collections::HashMap;
+use std::fs;
+use std::path::{Path, PathBuf};
 use std::sync::Mutex;
+use tempfile::NamedTempFile;
 
 /// 安全地序列化 JSON，避免 unwrap panic
 fn to_json_string<T: Serialize>(value: &T) -> Result<String, AppError> {
@@ -25,6 +31,8 @@ macro_rules! lock_conn {
     };
 }
 
+const DB_BACKUP_RETAIN: usize = 10;
+
 pub struct Database {
     // 使用 Mutex 包装 Connection 以支持在多线程环境（如 Tauri State）中共享
     // rusqlite::Connection 本身不是 Sync 的
@@ -57,7 +65,10 @@ impl Database {
 
     fn create_tables(&self) -> Result<(), AppError> {
         let conn = lock_conn!(self.conn);
+        Self::create_tables_on_conn(&conn)
+    }
 
+    fn create_tables_on_conn(conn: &Connection) -> Result<(), AppError> {
         // 1. Providers 表
         conn.execute(
             "CREATE TABLE IF NOT EXISTS providers (
@@ -166,6 +177,308 @@ impl Database {
         Ok(())
     }
 
+    /// 创建内存快照以避免长时间持有数据库锁
+    fn snapshot_to_memory(&self) -> Result<Connection, AppError> {
+        let conn = lock_conn!(self.conn);
+        let mut snapshot =
+            Connection::open_in_memory().map_err(|e| AppError::Database(e.to_string()))?;
+
+        {
+            let backup =
+                Backup::new(&conn, &mut snapshot).map_err(|e| AppError::Database(e.to_string()))?;
+            backup
+                .step(-1)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+        }
+
+        Ok(snapshot)
+    }
+
+    /// 导出为 SQLite 兼容的 SQL 文本
+    pub fn export_sql(&self, target_path: &Path) -> Result<(), AppError> {
+        let snapshot = self.snapshot_to_memory()?;
+        let dump = Self::dump_sql(&snapshot)?;
+
+        if let Some(parent) = target_path.parent() {
+            fs::create_dir_all(parent).map_err(|e| AppError::io(parent, e))?;
+        }
+
+        crate::config::atomic_write(target_path, dump.as_bytes())
+    }
+
+    /// 从 SQL 文件导入，返回生成的备份 ID（若无备份则为空字符串）
+    pub fn import_sql(&self, source_path: &Path) -> Result<String, AppError> {
+        if !source_path.exists() {
+            return Err(AppError::InvalidInput(format!(
+                "SQL 文件不存在: {}",
+                source_path.display()
+            )));
+        }
+
+        let sql_raw = fs::read_to_string(source_path).map_err(|e| AppError::io(source_path, e))?;
+        let sql_content = Self::sanitize_import_sql(&sql_raw);
+
+        // 导入前备份现有数据库
+        let backup_path = self.backup_database_file()?;
+
+        // 在临时数据库执行导入，确保失败不会污染主库
+        let temp_file = NamedTempFile::new().map_err(|e| AppError::IoContext {
+            context: "创建临时数据库文件失败".to_string(),
+            source: e,
+        })?;
+        let temp_path = temp_file.path().to_path_buf();
+        let temp_conn =
+            Connection::open(&temp_path).map_err(|e| AppError::Database(e.to_string()))?;
+
+        temp_conn
+            .execute_batch(&sql_content)
+            .map_err(|e| AppError::Database(format!("执行 SQL 导入失败: {e}")))?;
+
+        // 补齐缺失表/索引并进行基础校验
+        Self::create_tables_on_conn(&temp_conn)?;
+        Self::validate_basic_state(&temp_conn)?;
+
+        // 使用 Backup 将临时库原子写回主库
+        {
+            let mut main_conn = lock_conn!(self.conn);
+            let backup = Backup::new(&temp_conn, &mut *main_conn)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+            backup
+                .step(-1)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+        }
+
+        let backup_id = backup_path
+            .and_then(|p| p.file_stem().map(|s| s.to_string_lossy().to_string()))
+            .unwrap_or_default();
+
+        Ok(backup_id)
+    }
+
+    /// 移除 SQLite 保留对象相关语句（如 sqlite_sequence），避免导入报错
+    fn sanitize_import_sql(sql: &str) -> String {
+        let mut cleaned = String::new();
+        let lower_keyword = "sqlite_sequence";
+
+        for stmt in sql.split(';') {
+            let trimmed = stmt.trim();
+            if trimmed.is_empty() {
+                continue;
+            }
+
+            if trimmed.to_ascii_lowercase().contains(lower_keyword) {
+                continue;
+            }
+
+            cleaned.push_str(trimmed);
+            cleaned.push_str(";\n");
+        }
+
+        cleaned
+    }
+
+    /// 生成一致性快照备份，返回备份文件路径（不存在主库时返回 None）
+    fn backup_database_file(&self) -> Result<Option<PathBuf>, AppError> {
+        let db_path = get_app_config_dir().join("cc-switch.db");
+        if !db_path.exists() {
+            return Ok(None);
+        }
+
+        let backup_dir = db_path
+            .parent()
+            .ok_or_else(|| AppError::Config("无效的数据库路径".to_string()))?
+            .join("backups");
+
+        fs::create_dir_all(&backup_dir).map_err(|e| AppError::io(&backup_dir, e))?;
+
+        let backup_id = format!("db_backup_{}", Utc::now().format("%Y%m%d_%H%M%S"));
+        let backup_path = backup_dir.join(format!("{backup_id}.db"));
+
+        {
+            let conn = lock_conn!(self.conn);
+            let mut dest_conn =
+                Connection::open(&backup_path).map_err(|e| AppError::Database(e.to_string()))?;
+            let backup = Backup::new(&conn, &mut dest_conn)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+            backup
+                .step(-1)
+                .map_err(|e| AppError::Database(e.to_string()))?;
+        }
+
+        Self::cleanup_db_backups(&backup_dir)?;
+        Ok(Some(backup_path))
+    }
+
+    fn cleanup_db_backups(dir: &Path) -> Result<(), AppError> {
+        let entries = match fs::read_dir(dir) {
+            Ok(iter) => iter
+                .filter_map(|entry| entry.ok())
+                .filter(|entry| {
+                    entry
+                        .path()
+                        .extension()
+                        .map(|ext| ext == "db")
+                        .unwrap_or(false)
+                })
+                .collect::<Vec<_>>(),
+            Err(_) => return Ok(()),
+        };
+
+        if entries.len() <= DB_BACKUP_RETAIN {
+            return Ok(());
+        }
+
+        let remove_count = entries.len().saturating_sub(DB_BACKUP_RETAIN);
+        let mut sorted = entries;
+        sorted.sort_by_key(|entry| entry.metadata().and_then(|m| m.modified()).ok());
+
+        for entry in sorted.into_iter().take(remove_count) {
+            if let Err(err) = fs::remove_file(entry.path()) {
+                log::warn!("删除旧数据库备份失败 {}: {}", entry.path().display(), err);
+            }
+        }
+        Ok(())
+    }
+
+    fn validate_basic_state(conn: &Connection) -> Result<(), AppError> {
+        let provider_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM providers", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        let mcp_count: i64 = conn
+            .query_row("SELECT COUNT(*) FROM mcp_servers", [], |row| row.get(0))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        if provider_count == 0 && mcp_count == 0 {
+            return Err(AppError::Config(
+                "导入的 SQL 未包含有效的供应商或 MCP 数据".to_string(),
+            ));
+        }
+        Ok(())
+    }
+
+    fn dump_sql(conn: &Connection) -> Result<String, AppError> {
+        let mut output = String::new();
+        let timestamp = Utc::now().format("%Y-%m-%d %H:%M:%S").to_string();
+        let user_version: i64 = conn
+            .query_row("PRAGMA user_version;", [], |row| row.get(0))
+            .unwrap_or(0);
+
+        output.push_str(&format!(
+            "-- CC Switch SQLite 导出\n-- 生成时间: {timestamp}\n-- user_version: {user_version}\n"
+        ));
+        output.push_str("PRAGMA foreign_keys=OFF;\n");
+        output.push_str(&format!("PRAGMA user_version={user_version};\n"));
+        output.push_str("BEGIN TRANSACTION;\n");
+
+        // 导出 schema
+        let mut stmt = conn
+            .prepare(
+                "SELECT type, name, tbl_name, sql 
+                 FROM sqlite_master 
+                 WHERE sql NOT NULL AND type IN ('table','index','trigger','view')
+                 ORDER BY type='table' DESC, name",
+            )
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut tables = Vec::new();
+        let mut rows = stmt
+            .query([])
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        while let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+            let obj_type: String = row.get(0).map_err(|e| AppError::Database(e.to_string()))?;
+            let name: String = row.get(1).map_err(|e| AppError::Database(e.to_string()))?;
+            let sql: String = row.get(3).map_err(|e| AppError::Database(e.to_string()))?;
+
+            // 跳过 SQLite 内部对象（如 sqlite_sequence）
+            if name.starts_with("sqlite_") {
+                continue;
+            }
+
+            output.push_str(&sql);
+            output.push_str(";\n");
+
+            if obj_type == "table" && !name.starts_with("sqlite_") {
+                tables.push(name);
+            }
+        }
+
+        // 导出数据
+        for table in tables {
+            let columns = Self::get_table_columns(conn, &table)?;
+            if columns.is_empty() {
+                continue;
+            }
+
+            let mut stmt = conn
+                .prepare(&format!("SELECT * FROM \"{table}\""))
+                .map_err(|e| AppError::Database(e.to_string()))?;
+            let mut rows = stmt
+                .query([])
+                .map_err(|e| AppError::Database(e.to_string()))?;
+
+            while let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
+                let mut values = Vec::with_capacity(columns.len());
+                for idx in 0..columns.len() {
+                    let value = row
+                        .get_ref(idx)
+                        .map_err(|e| AppError::Database(e.to_string()))?;
+                    values.push(Self::format_sql_value(value)?);
+                }
+
+                let cols = columns
+                    .iter()
+                    .map(|c| format!("\"{c}\""))
+                    .collect::<Vec<_>>()
+                    .join(", ");
+                output.push_str(&format!(
+                    "INSERT INTO \"{table}\" ({cols}) VALUES ({});\n",
+                    values.join(", ")
+                ));
+            }
+        }
+
+        output.push_str("COMMIT;\nPRAGMA foreign_keys=ON;\n");
+        Ok(output)
+    }
+
+    fn get_table_columns(conn: &Connection, table: &str) -> Result<Vec<String>, AppError> {
+        let mut stmt = conn
+            .prepare(&format!("PRAGMA table_info(\"{table}\")"))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        let iter = stmt
+            .query_map([], |row| row.get::<_, String>(1))
+            .map_err(|e| AppError::Database(e.to_string()))?;
+
+        let mut columns = Vec::new();
+        for col in iter {
+            columns.push(col.map_err(|e| AppError::Database(e.to_string()))?);
+        }
+        Ok(columns)
+    }
+
+    fn format_sql_value(value: ValueRef<'_>) -> Result<String, AppError> {
+        match value {
+            ValueRef::Null => Ok("NULL".to_string()),
+            ValueRef::Integer(i) => Ok(i.to_string()),
+            ValueRef::Real(f) => Ok(f.to_string()),
+            ValueRef::Text(t) => {
+                let text = std::str::from_utf8(t)
+                    .map_err(|e| AppError::Database(format!("文本字段不是有效的 UTF-8: {e}")))?;
+                let escaped = text.replace('\'', "''");
+                Ok(format!("'{escaped}'"))
+            }
+            ValueRef::Blob(bytes) => {
+                let mut s = String::from("X'");
+                for b in bytes {
+                    use std::fmt::Write;
+                    let _ = write!(&mut s, "{b:02X}");
+                }
+                s.push('\'');
+                Ok(s)
+            }
+        }
+    }
+
     /// 从 MultiAppConfig 迁移数据
     pub fn migrate_from_json(&self, config: &MultiAppConfig) -> Result<(), AppError> {
         let mut conn = lock_conn!(self.conn);