feat(#7): implement LoadAndroidDB function and add tests for loading ekeys from QQ Music Android SQLite database

algo/qmc/key_android_db_loader.go

@@ -0,0 +1,110 @@
+package qmc
+
+import (
+	"database/sql"
+	"fmt"
+	"path/filepath"
+
+	"git.um-react.app/um/cli/algo/common"
+	"git.um-react.app/um/cli/internal/utils"
+	"go.uber.org/zap"
+	_ "modernc.org/sqlite"
+)
+
+// LoadAndroidDB loads QMC ekeys from a QQ Music Android SQLite DB
+// (player_process_db). Soft-fails with a warning.
+func LoadAndroidDB(path string, logger *zap.Logger) common.QMCKeys {
+	if path == "" {
+		return nil
+	}
+	logger.Debug("LoadAndroidDB: Loading Android DB", zap.String("path", path))
+
+	keys, err := loadAndroidDB(path)
+	if err != nil {
+		logger.Warn("LoadAndroidDB: could not read Android DB keys", zap.Error(err))
+		return nil
+	}
+	logger.Info("Using Android DB", zap.String("path", path), zap.Int("count", len(keys)))
+	return keys
+}
+
+func loadAndroidDB(path string) (common.QMCKeys, error) {
+	// mode=ro: refuse writes and do not create a missing database file.
+	dsn := "file:" + filepath.ToSlash(path) + "?mode=ro"
+	db, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("open: %w", err)
+	}
+	defer db.Close()
+
+	if err := db.Ping(); err != nil {
+		return nil, fmt.Errorf("ping: %w", err)
+	}
+
+	query, err := androidEKeyQuery(db)
+	if err != nil {
+		return nil, err
+	}
+
+	rows, err := db.Query(query)
+	if err != nil {
+		return nil, fmt.Errorf("query: %w", err)
+	}
+	defer rows.Close()
+
+	result := make(common.QMCKeys)
+	for rows.Next() {
+		var filePath, ekey string
+		if err := rows.Scan(&filePath, &ekey); err != nil {
+			return nil, fmt.Errorf("scan: %w", err)
+		}
+		filePath = utils.NormalizeUnicode(filePath)
+		ekey = utils.NormalizeUnicode(ekey)
+		if filePath == "" || ekey == "" {
+			continue
+		}
+		result[filePath] = ekey
+		if base := filepath.Base(filePath); base != filePath {
+			result[utils.NormalizeUnicode(base)] = ekey
+		}
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("rows: %w", err)
+	}
+	return result, nil
+}
+
+func androidEKeyQuery(db *sql.DB) (string, error) {
+	has, err := hasTable(db, "audio_file_ekey_table")
+	if err != nil {
+		return "", err
+	}
+	if has {
+		return "select file_path, ekey from audio_file_ekey_table", nil
+	}
+
+	has, err = hasTable(db, "EKeyFileInfo")
+	if err != nil {
+		return "", err
+	}
+	if has {
+		return "select filePath, eKey from EKeyFileInfo", nil
+	}
+
+	return "", fmt.Errorf("no known ekey table found (audio_file_ekey_table or EKeyFileInfo)")
+}
+
+func hasTable(db *sql.DB, name string) (bool, error) {
+	var found string
+	err := db.QueryRow(
+		`select name from sqlite_master where type='table' and name=?`,
+		name,
+	).Scan(&found)
+	if err == sql.ErrNoRows {
+		return false, nil
+	}
+	if err != nil {
+		return false, fmt.Errorf("hasTable(%s): %w", name, err)
+	}
+	return true, nil
+}