BPackageInfo: Add CanonicalFileName()

The name of the package file is not part of the package-info.
CanonicalFileName() constructs the name the file should have (not
enforced anywhere (yet)).

headers/os/package/PackageInfo.h

@@ -89,6 +89,8 @@ public:
 								FreshensList() const;
 			const BStringList&	ReplacesList() const;
 
+			BString				CanonicalFileName() const;
+
 			void				SetName(const BString& name);
 			void				SetSummary(const BString& summary);
 			void				SetDescription(const BString& description);

src/kits/package/PackageInfo.cpp

@@ -1590,6 +1590,17 @@ BPackageInfo::ReplacesList() const
 }
 
 
+BString
+BPackageInfo::CanonicalFileName() const
+{
+	if (InitCheck() != B_OK)
+		return BString();
+
+	return BString().SetToFormat("%s-%s-%s.hpkg", fName.String(),
+		fVersion.ToString().String(), kArchitectureNames[fArchitecture]);
+}
+
+
 void
 BPackageInfo::SetName(const BString& name)
 {