[packages] Move package-list-logic into PM base class

src/modules/packages/main.py

@@ -151,6 +151,82 @@ class PackageManager(metaclass=abc.ABCMeta):
             self.remove([packagedata["package"]])
             self.run(packagedata["post-script"])
 
+    def operation_install(self, package_list, from_local=False):
+        """
+        Installs the list of packages named in @p package_list .
+        These can be strings -- plain package names -- or
+        structures (with a pre- and post-install step).
+
+        This operation is called for "critical" packages,
+        which are expected to succeed, or fail, all together.
+        However, if there are packages with pre- or post-scripts,
+        then packages are installed one-by-one instead.
+
+        NOTE: package managers may reimplement this method
+        NOTE: exceptions are expected to leave this method, to indicate
+              failure of the installation.
+        """
+        if all([isinstance(x, str) for x in package_list]):
+            self.install(package_list, from_local=from_local)
+        else:
+            for package in package_list:
+                self.install_package(package, from_local=from_local)
+
+    def operation_try_install(self, package_list):
+        """
+        Installs the list of packages named in @p package_list .
+        These can be strings -- plain package names -- or
+        structures (with a pre- and post-install step).
+
+        This operation is called for "non-critical" packages,
+        which can succeed or fail without affecting the overall installation.
+        Packages are installed one-by-one to support package managers
+        that do not have a "install as much as you can" mode.
+
+        NOTE: package managers may reimplement this method
+        NOTE: no package-installation exceptions should be raised
+        """
+        # we make a separate package manager call for each package so a
+        # single failing package won't stop all of them
+        for package in package_list:
+            try:
+                self.install_package(package)
+            except subprocess.CalledProcessError:
+                libcalamares.utils.warning("Could not install package %s" % package)
+
+    def operation_remove(self, package_list):
+        """
+        Removes the list of packages named in @p package_list .
+        These can be strings -- plain package names -- or
+        structures (with a pre- and post-install step).
+
+        This operation is called for "critical" packages, which are
+        expected to succeed or fail all together.
+        However, if there are packages with pre- or post-scripts,
+        then packages are removed one-by-one instead.
+
+        NOTE: package managers may reimplement this method
+        NOTE: exceptions should be raised to indicate failure
+        """
+        if all([isinstance(x, str) for x in package_list]):
+            self.remove(package_list)
+        else:
+            for package in package_list:
+                self.remove_package(package)
+
+    def operation_try_remove(self, package_list):
+        """
+        Same relation as try_install has to install, except it removes
+        packages instead. Packages are removed one-by-one.
+
+        NOTE: package managers may reimplement this method
+        NOTE: no package-installation exceptions should be raised
+        """
+        for package in package_list:
+            try:
+                self.remove_package(package)
+            except subprocess.CalledProcessError:
+                libcalamares.utils.warning("Could not remove package %s" % package)
 
 ### PACKAGE MANAGER IMPLEMENTATIONS
 #
@@ -503,45 +579,19 @@ def run_operations(pkgman, entry):
         group_packages = len(package_list)
         if key == "install":
             _change_mode(INSTALL)
-            if all([isinstance(x, str) for x in package_list]):
-                pkgman.install(package_list)
-            else:
-                for package in package_list:
-                    pkgman.install_package(package)
+            pkgman.operation_install(package_list)
         elif key == "try_install":
             _change_mode(INSTALL)
-            # we make a separate package manager call for each package so a
-            # single failing package won't stop all of them
-            for package in package_list:
-                try:
-                    pkgman.install_package(package)
-                except subprocess.CalledProcessError:
-                    warn_text = "Could not install package "
-                    warn_text += str(package)
-                    libcalamares.utils.warning(warn_text)
+            pkgman.operation_try_install(package_list)
         elif key == "remove":
             _change_mode(REMOVE)
-            if all([isinstance(x, str) for x in package_list]):
-                pkgman.remove(package_list)
-            else:
-                for package in package_list:
-                    pkgman.remove_package(package)
+            pkgman.operation_remove(package_list)
         elif key == "try_remove":
             _change_mode(REMOVE)
-            for package in package_list:
-                try:
-                    pkgman.remove_package(package)
-                except subprocess.CalledProcessError:
-                    warn_text = "Could not remove package "
-                    warn_text += str(package)
-                    libcalamares.utils.warning(warn_text)
+            pkgman.operation_try_remove(package_list)
         elif key == "localInstall":
             _change_mode(INSTALL)
-            if all([isinstance(x, str) for x in package_list]):
-                pkgman.install(package_list, from_local=True)
-            else:
-                for package in package_list:
-                    pkgman.install_package(package, from_local=True)
+            pkgman.operation_install(package_list, from_local=True)
         elif key == "source":
             libcalamares.utils.debug("Package-list from {!s}".format(entry[key]))
         else: