Extract OSC 7 hostname parsing into helper functions

src/termio/stream_handler.zig

@@ -1030,6 +1030,48 @@ pub const StreamHandler = struct {
         self.terminal.markSemanticPrompt(.command);
     }
 
+    pub fn bufPrintHostnameFromFileUri(buf: []u8, uri: std.Uri) ![]const u8 {
+        // Get the raw string of the URI. Its unclear to me if the various
+        // tags of this enum guarantee no percent-encoding so we just
+        // check all of it. This isn't a performance critical path.
+        const host_component = uri.host orelse return error.NoHostnameInUri;
+        const host = switch (host_component) {
+            .raw => |v| v,
+            .percent_encoded => |v| v,
+        };
+
+        // When the "Private Wi-Fi address" setting is toggled on macOS the hostname
+        // is set to a string of digits separated by a colon, e.g. '12:34:56:78:90:12'.
+        // The URI will be parsed as if the last set o digit is a port, so we need to
+        // make sure that part is included when it's set.
+        if (uri.port) |port| {
+            var fbs = std.io.fixedBufferStream(buf);
+            std.fmt.format(fbs.writer().any(), "{s}:{d}", .{ host, port }) catch |err| switch (err) {
+                error.NoSpaceLeft => return error.NoSpaceLeft,
+                else => unreachable,
+            };
+
+            return fbs.getWritten();
+        }
+
+        return host;
+    }
+
+    pub fn isLocalHostname(hostname: []const u8) !bool {
+        // A 'localhost' hostname is always considered local.
+        if (std.mem.eql(u8, "localhost", hostname)) {
+            return true;
+        }
+
+        // If hostname is not "localhost" it must match our hostname.
+        var buf: [posix.HOST_NAME_MAX]u8 = undefined;
+        const ourHostname = posix.gethostname(&buf) catch |err| {
+            return err;
+        };
+
+        return std.mem.eql(u8, hostname, ourHostname);
+    }
+
     pub fn reportPwd(self: *StreamHandler, url: []const u8) !void {
         if (builtin.os.tag == .windows) {
             log.warn("reportPwd unimplemented on windows", .{});
@@ -1048,57 +1090,34 @@ pub const StreamHandler = struct {
             return;
         }
 
+        // RFC 793 defines port numbers as 16-bit numbers. 5 digits is sufficient to represent
+        // the maximum since 2^16 - 1 = 65_535.
+        // See https://www.rfc-editor.org/rfc/rfc793#section-3.1.
+        const PORT_NUMBER_MAX_DIGITS = 5;
+        // Make sure there is space for a max length hostname + the max number of digits.
+        var host_and_port_buf: [posix.HOST_NAME_MAX + PORT_NUMBER_MAX_DIGITS]u8 = undefined;
+
+        const hostname = bufPrintHostnameFromFileUri(&host_and_port_buf, uri) catch |err| switch (err) {
+            error.NoHostnameInUri => {
+                log.warn("OSC 7 uri must contain a hostname: {}", .{err});
+                return;
+            },
+            error.NoSpaceLeft => |e| {
+                log.warn("failed to get full hostname for OSC 7 validation: {}", .{e});
+                return;
+            },
+        };
+
         // OSC 7 is a little sketchy because anyone can send any value from
         // any host (such an SSH session). The best practice terminals follow
         // is to valid the hostname to be local.
-        const host_valid = host_valid: {
+        const host_valid = isLocalHostname(hostname) catch |err| switch (err) {
-            const host_component = uri.host orelse break :host_valid false;
+            error.PermissionDenied, error.Unexpected => {
-
-            // Get the raw string of the URI. Its unclear to me if the various
-            // tags of this enum guarantee no percent-encoding so we just
-            // check all of it. This isn't a performance critical path.
-            const host = host: {
-                const h = switch (host_component) {
-                    .raw => |v| v,
-                    .percent_encoded => |v| v,
-                };
-                if (h.len == 0 or std.mem.eql(u8, "localhost", h)) {
-                    break :host_valid true;
-                }
-
-                // When the "Private Wi-Fi address" setting is toggled on macOS the hostname
-                // is set to a string of digits separated by a colon, e.g. '12:34:56:78:90:12'.
-                // The URI will be parsed as if the last set o digit is a port, so we need to
-                // make sure that part is included when it's set.
-                if (uri.port) |port| {
-                    // RFC 793 defines port numbers as 16-bit numbers. 5 digits is sufficient to represent
-                    // the maximum since 2^16 - 1 = 65_535.
-                    // See https://www.rfc-editor.org/rfc/rfc793#section-3.1.
-                    const PORT_NUMBER_MAX_DIGITS = 5;
-
-                    // Make sure there is space for a max length hostname + the max number of digits.
-                    var host_and_port_buf: [posix.HOST_NAME_MAX + PORT_NUMBER_MAX_DIGITS]u8 = undefined;
-
-                    const host_and_port = std.fmt.bufPrint(&host_and_port_buf, "{s}:{d}", .{ h, port }) catch |err| {
-                        log.warn("failed to get full hostname for OSC 7 validation: {}", .{err});
-                        break :host_valid false;
-                    };
-
-                    break :host host_and_port;
-                } else {
-                    break :host h;
-                }
-            };
-
-            // Otherwise, it must match our hostname.
-            var buf: [posix.HOST_NAME_MAX]u8 = undefined;
-            const hostname = posix.gethostname(&buf) catch |err| {
                 log.warn("failed to get hostname for OSC 7 validation: {}", .{err});
-                break :host_valid false;
+                return;
-            };
+            },
-
-            break :host_valid std.mem.eql(u8, host, hostname);
         };
+
         if (!host_valid) {
             log.warn("OSC 7 host must be local", .{});
             return;