List WIP

GRDB/Dump/DumpFormats/ListDumpFormat.swift

@@ -0,0 +1,130 @@
+import Foundation
+
+/// A format that prints one line per database row.
+///
+/// On each line, database values are separated by a separator (`|`
+/// by default). Blob values are interpreted as UTF8 strings.
+///
+/// For example:
+///
+/// ```swift
+/// // Arthur|500
+/// // Barbara|1000
+/// // Craig|200
+/// try db.dumpRequest(Player.all(), format: .debug())
+/// ```
+public struct ListDumpFormat {
+    /// A boolean value indicating if column labels are printed as the first
+    /// line of output.
+    public var header: Bool
+
+    /// The separator between values.
+    public var separator: String
+
+    /// The string to print for NULL values.
+    public var nullValue: String
+
+    private var firstRow = true
+
+    /// Creates a `ListDumpFormat`.
+    ///
+    /// - Parameters:
+    ///   - header: A boolean value indicating if column labels are printed
+    ///     as the first line of output.
+    ///   - separator: The separator between values.
+    ///   - nullValue: The string to print for NULL values.
+    public init(
+        header: Bool = false,
+        separator: String = "|",
+        nullValue: String = "")
+    {
+        self.header = header
+        self.separator = separator
+        self.nullValue = nullValue
+    }
+}
+
+extension ListDumpFormat: DumpFormat {
+    public mutating func writeRow(
+        _ db: Database,
+        statement: Statement,
+        to stream: inout some TextOutputStream)
+    {
+        if firstRow {
+            firstRow = false
+            if header {
+                stream.writeln(statement.columnNames.joined(separator: separator))
+            }
+        }
+
+        let sqliteStatement = statement.sqliteStatement
+        var first = true
+        for index in 0..<sqlite3_column_count(sqliteStatement) {
+            // Don't log GRDB columns
+            let column = String(cString: sqlite3_column_name(sqliteStatement, index))
+            if column.starts(with: "grdb_") { continue }
+
+            if first {
+                first = false
+            } else {
+                stream.write(separator)
+            }
+
+            stream.write(formattedValue(db, in: sqliteStatement, at: index))
+        }
+        stream.write("\n")
+    }
+
+    public mutating func finalize(_ db: Database, statement: Statement, to stream: inout some TextOutputStream) {
+        firstRow = true
+    }
+
+    private func formattedValue(_ db: Database, in sqliteStatement: SQLiteStatement, at index: CInt) -> String {
+        switch sqlite3_column_type(sqliteStatement, index) {
+        case SQLITE_NULL:
+            return nullValue
+
+        case SQLITE_INTEGER:
+            return Int64(sqliteStatement: sqliteStatement, index: index).description
+
+        case SQLITE_FLOAT:
+            return Double(sqliteStatement: sqliteStatement, index: index).description
+
+        case SQLITE_BLOB, SQLITE_TEXT:
+            return String(sqliteStatement: sqliteStatement, index: index)
+
+        default:
+            return ""
+        }
+    }
+}
+
+extension DumpFormat where Self == ListDumpFormat {
+    /// A format that prints one line per database row.
+    ///
+    /// On each line, database values are separated by a separator (`|`
+    /// by default). Blob values are interpreted as UTF8 strings.
+    ///
+    /// For example:
+    ///
+    /// ```swift
+    /// // Arthur|500
+    /// // Barbara|1000
+    /// // Craig|200
+    /// try db.dumpRequest(Player.all(), format: .debug())
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - header: A boolean value indicating if column labels are printed
+    ///     as the first line of output.
+    ///   - separator: The separator between values.
+    ///   - nullValue: The string to print for NULL values.
+    public static func list(
+        header: Bool = false,
+        separator: String = "|",
+        nullValue: String = "")
+    -> Self
+    {
+        ListDumpFormat(header: header, separator: separator, nullValue: nullValue)
+    }
+}