use arena allocator, because this is a short lived cli tool

src/main.zig

@@ -16,15 +16,13 @@ const Base32Error = @import("base32.zig").Base32Error;
 pub fn main() !void {
     mainInternal() catch |err| {
         switch (err) {
-            Base32Error.InvalidCharacter => {
-                try std.io.getStdErr().writer().print("The secret is invalid.\n", .{});
-            },
-            Base32Error.InvalidPadding => {
+            Base32Error.InvalidCharacter, Base32Error.InvalidPadding => {
                 try std.io.getStdErr().writer().print("The secret is invalid.\n", .{});
             },
             ArgumentError.UnknownParameter => {
-                try std.io.getStdErr().writer().print("Unknown argument\n", .{});
+                // do nothing, error message is already written (because the message contains the name of the unknown parameter)
             },
+            ArgumentError.InvalidOtpAuthUrl => {},
             else => |leftover_err| {
                 try std.io.getStdErr().writer().print("{?}\n", .{leftover_err});
             },
@@ -34,8 +32,9 @@ pub fn main() !void {
 }
 
 fn mainInternal() !void {
-    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
-    const allocator = gpa.allocator();
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+    const allocator = arena.allocator();
 
     const args = try std.process.argsAlloc(allocator);
 
@@ -171,15 +170,14 @@ fn parseArgs(allocator: Allocator, args: []const []const u8) !Args {
             }
             result.show = args[i];
         } else {
-            std.debug.print("unknown parameter: {s}\n", .{arg});
+            std.debug.print("unknown argument: {s}\n", .{arg});
             return ArgumentError.UnknownParameter;
         }
     }
     return result;
 }
 
-// todo use a real url parser
-fn parseOtpAuthUrl(url: []const u8) !OtpAuthUrl {
+fn parseOtpAuthUrl(allocator: Allocator, url: []const u8) !OtpAuthUrl {
     const uri = try std.Uri.parse(url);
 
     if (!eql(u8, uri.scheme, "otpauth")) {
@@ -190,9 +188,6 @@ fn parseOtpAuthUrl(url: []const u8) !OtpAuthUrl {
         return error.InvalidOtpAuthUrl;
     }
 
-    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
-    const allocator = gpa.allocator();
-
     var name = try uri.path.toRawMaybeAlloc(allocator);
     name = std.mem.trimLeft(u8, name, "/");
 
@@ -259,12 +254,26 @@ fn read_config(allocator: Allocator, config_location: []const u8) !ArrayList(Otp
 
     var authenticators = std.ArrayList(OtpAuthUrl).init(allocator);
 
+    var line_no: usize = 1;
     while (try in_stream.readUntilDelimiterOrEofAlloc(allocator, '\n', 1024 * 1024)) |line| {
+        //defer allocator.free(line);
         if (line.len > 0 and std.mem.trim(u8, line, " \r").len > 0) {
-            const authenticator = try parseOtpAuthUrl(line);
+            const authenticatorResult = parseOtpAuthUrl(allocator, line);
+            if (authenticatorResult) |authenticator| {
                 try authenticators.append(authenticator);
+            } else |err| {
+                switch (err) {
+                    error.InvalidOtpAuthUrl => {
+                        try std.io.getStdErr().writer().print("invalid otpauth url in line {d}\n", .{line_no});
+                    },
+                    else => {
+                        return err;
+                    },
                 }
             }
+        }
+        line_no += 1;
+    }
     return authenticators;
 }
 
@@ -294,16 +303,18 @@ fn getAuthenticator(allocator: Allocator, name: []const u8, config_location: []c
 }
 
 test "parse command line parameter: 'list'" {
-    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
-    const allocator = gpa.allocator();
+    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
+    defer arena.deinit();
+    const allocator = arena.allocator();
 
     const arg = try parseArgs(allocator, &[_][]const u8{ "path/of/executable", "list" });
     try expect(arg.list);
 }
 
 test "read list of entries" {
-    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
-    const allocator = gpa.allocator();
+    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
+    defer arena.deinit();
+    const allocator = arena.allocator();
 
     std.fs.cwd().deleteTree("test-tmp") catch unreachable;
     try std.fs.cwd().makeDir("test-tmp");
@@ -313,7 +324,7 @@ test "read list of entries" {
         std.fs.cwd().deleteTree("test-tmp") catch unreachable;
     }
 
-    _ = try file.write("otpauth://totp/token1?secret=c2VjcmV0Cg==\notpauth://totp/token2?secret=c2VjcmV0Cg==\n");
+    _ = try file.write("otpauth://totp/token1?secret=c2VjcmV0Cg==\notpauth://totp/token2?secret=c2VjcmV0Cg==");
 
     const list: std.ArrayList([]const u8) = try executeGetList(allocator, "test-tmp/zig-totp");
     try std.testing.expectEqualStrings("token1", list.items[0]);
@@ -321,8 +332,33 @@ test "read list of entries" {
     try std.testing.expectEqual(2, list.items.len);
 }
 
+test "read list of entries, ignoring invalid otpauth urls" {
+    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
+    defer arena.deinit();
+    const allocator = arena.allocator();
+
+    std.fs.cwd().deleteTree("test-tmp") catch unreachable;
+    try std.fs.cwd().makeDir("test-tmp");
+    const file = try std.fs.cwd().createFile("test-tmp/zig-totp", .{ .read = true });
+    defer {
+        file.close();
+        std.fs.cwd().deleteTree("test-tmp") catch unreachable;
+    }
+
+    _ = try file.write("otpauth://totp/token1?secret=c2VjcmV0Cg==\notpauth://invalid\n");
+
+    const list: std.ArrayList([]const u8) = try executeGetList(allocator, "test-tmp/zig-totp");
+
+    try std.testing.expectEqualStrings("token1", list.items[0]);
+    try std.testing.expectEqual(1, list.items.len);
+}
+
 test "parse oth pauth url" {
-    const actual: OtpAuthUrl = try parseOtpAuthUrl("otpauth://totp/foo?secret=MFQQ&period=31&digits=7");
+    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
+    defer arena.deinit();
+    const allocator = arena.allocator();
+
+    const actual: OtpAuthUrl = try parseOtpAuthUrl(allocator, "otpauth://totp/foo?secret=MFQQ&period=31&digits=7");
 
     try std.testing.expectEqualStrings("MFQQ", actual.secretEncoded);
     try std.testing.expectEqualStrings("foo", actual.name);