Initial commit

vendor/go.i3wm.org/i3/version.go

@@ -0,0 +1,62 @@
+package i3
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+)
+
+// Version describes an i3 version.
+//
+// See https://i3wm.org/docs/ipc.html#_version_reply for more details.
+type Version struct {
+	Major                int64  `json:"major"`
+	Minor                int64  `json:"minor"`
+	Patch                int64  `json:"patch"`
+	Variant              string `json:"variant,omitempty"`
+	HumanReadable        string `json:"human_readable"`
+	LoadedConfigFileName string `json:"loaded_config_file_name"`
+}
+
+// GetVersion returns i3’s version.
+//
+// GetVersion is supported in i3 ≥ v4.3 (2012-09-19).
+func GetVersion() (Version, error) {
+	reply, err := roundTrip(messageTypeGetVersion, nil)
+	if err != nil {
+		return Version{}, err
+	}
+
+	var v Version
+	err = json.Unmarshal(reply.Payload, &v)
+	return v, err
+}
+
+// version is a lazily-initialized, possibly stale copy of i3’s GET_VERSION
+// reply. Access only values which don’t change, e.g. Major, Minor.
+var version Version
+
+// AtLeast returns nil if i3’s major version matches major and i3’s minor
+// version is at least minor or newer. Otherwise, it returns an error message
+// stating i3 is too old.
+func AtLeast(major int64, minor int64) error {
+	if major == 0 {
+		return fmt.Errorf("BUG: major == 0 is non-sensical. Is a lookup table entry missing?")
+	}
+	if version.Major == 0 {
+		var err error
+		version, err = GetVersion()
+		if err != nil {
+			return err
+		}
+	}
+	if version.Variant != "" {
+		log.Printf("non standard i3 payload variant '%s' detected. Ignoring version check. This is fully unsupported.", version.Variant)
+		return nil
+	}
+	if version.Major == major && version.Minor >= minor {
+		return nil
+	}
+
+	return fmt.Errorf("i3 version too old: got %d.%d, want ≥ %d.%d", version.Major, version.Minor, major, minor)
+}