go: allow more comparison operators for mod dependencies

Added support for ==, !=, >, <, >=, <= when checking the base dependency version.

Author: sean-callahan

src/mod_modInfo.go

@@ -75,6 +75,7 @@ func (modInfoList *ModInfoList) listInstalledMods() error {
 			modInfo.FileName = info.Name()
 
 			var base Version
+			var op string
 			for _, dep := range modInfo.Dependencies {
 				dep = strings.TrimSpace(dep)
 				if dep == "" {
@@ -91,13 +92,11 @@ func (modInfoList *ModInfoList) listInstalledMods() error {
 				}
 				if len(parts) == 1 {
 					base = modInfo.FactorioVersion
+					op = ">="
 					continue
 				}
 
-				if parts[1] != ">=" {
-					log.Printf("skipping dependency '%s' in '%s': unsupported comparison\n", dep, modInfo.Name)
-					continue
-				}
+				op = parts[1]
 
 				if err := base.UnmarshalText([]byte(parts[2])); err != nil {
 					log.Printf("skipping dependency '%s' in '%s': %v\n", dep, modInfo.Name, err)
@@ -108,7 +107,7 @@ func (modInfoList *ModInfoList) listInstalledMods() error {
 			}
 
 			if !base.Equals(NilVersion) {
-				modInfo.Compatibility = !FactorioServ.Version.Less(base)
+				modInfo.Compatibility = FactorioServ.Version.Compare(base, op)
 			} else {
 				log.Println("error finding basemodDependency. Using FactorioVersion...")
 				modInfo.Compatibility = !FactorioServ.Version.Less(modInfo.FactorioVersion)

src/version.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 )
 
+// NilVersion represents an empty version number
 var NilVersion = Version{0, 0, 0}
 
 // Version represents a semantic version
@@ -51,3 +52,30 @@ func (v Version) Less(b Version) bool {
 		return false
 	}
 }
+
+// Greater returns true if the receiver version is greater than the argument version
+func (v Version) Greater(b Version) bool { return !v.Equals(b) && !v.Less(b) }
+
+func (v Version) ge(b Version) bool { return v.Equals(b) || v.Greater(b) }
+func (v Version) le(b Version) bool { return v.Equals(b) || v.Less(b) }
+
+// Compare returns true if the comparison between the two version operands is valid.
+// Supported ops are: ==, !=, >, <, >=, <=
+func (v Version) Compare(b Version, op string) bool {
+	switch op {
+	case "==":
+		return v.Equals(b)
+	case "!=":
+		return !v.Equals(b)
+	case ">":
+		return v.Greater(b)
+	case "<":
+		return v.Less(b)
+	case ">=":
+		return v.ge(b)
+	case "<=":
+		return v.le(b)
+	default:
+		panic("unsupported operator")
+	}
+}