Add Reboot Check to BPackageRoster

A bit of an explanation for these weirdly named functions:
LatestActivePackageInfos() returns the packages on the system that are
both installed and fully set up. When packages are in the middle of being
installed, LatestInactivePackageInfos() shows the packages in the process
of being installed. Once the installation process is done,
LatestInactivePackageInfos() returns nothing. If there are packages that
can't be fully activated without a reboot, CurrentlyActivePackageInfos()
will return the same information as LatestActivePackageInfos(), or if
everything has been installed and activated, it will return no packages.

Change-Id: Ia1814a5abda6d815c46e0b46dc812b4e7af81de3
Reviewed-on: https://review.haiku-os.org/c/1129
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

headers/os/package/PackageRoster.h

@@ -56,6 +56,8 @@ public:
 								BPackageRoster();
 								~BPackageRoster();
 
+			bool				IsRebootNeeded();
+
 			status_t			GetCommonRepositoryCachePath(BPath* path,
 									bool create = false) const;
 			status_t			GetUserRepositoryCachePath(BPath* path,

src/kits/package/PackageRoster.cpp

@@ -52,6 +52,27 @@ BPackageRoster::~BPackageRoster()
 }
 
 
+bool
+BPackageRoster::IsRebootNeeded()
+{
+	BInstallationLocationInfo info;
+
+	// We get information on the system package installation location.
+	// If we fail, we just have to assume a reboot is not needed.
+	if (GetInstallationLocationInfo(B_PACKAGE_INSTALLATION_LOCATION_SYSTEM,
+		info) != B_OK)
+		return false;
+
+	// CurrentlyActivePackageInfos() will return 0 if no packages need to be
+	// activated with a reboot. Otherwise, the method will return the total
+	// number of packages in the system package directory.
+	if (info.CurrentlyActivePackageInfos().CountInfos() != 0)
+		return true;
+
+	return false;
+}
+
+
 status_t
 BPackageRoster::GetCommonRepositoryConfigPath(BPath* path, bool create) const
 {