Redo update system to work with batched updates

core/interfaces.go

@@ -1,16 +1,43 @@
 package core
-// UpdateParsers stores all the update parsers that packwiz can use. Add your own update systems to this map.
-var UpdateParsers = make(map[string]UpdateParser)
 
-// UpdateParser takes an unparsed interface{} (as a map[string]interface{}), and returns an Updater for a mod file.
-// This can be done using the mapstructure library or your own parsing methods.
-type UpdateParser interface {
-	ParseUpdate(map[string]interface{}) (Updater, error)
-}
+// Updaters stores all the updaters that packwiz can use. Add your own update systems to this map, keyed by the configuration name.
+var Updaters = make(map[string]Updater)
 
-// Updater checks for and does updates on a mod
+// Updater is used to process updates on mods
 type Updater interface {
-	// DoUpdate returns true if an update was done, false otherwise
-	DoUpdate(Mod) (bool, error)
+	// ParseUpdate takes an unparsed interface{} (as a map[string]interface{}), and returns an Updater for a mod file.
+	// This can be done using the mapstructure library or your own parsing methods.
+	ParseUpdate(map[string]interface{}) (interface{}, error)
+	// CheckUpdate checks whether there is an update for each of the mods in the given slice,
+	// called for all of the mods that this updater handles
+	CheckUpdate([]Mod) ([]UpdateCheck, error)
+	// DoUpdate carries out the update previously queried in CheckUpdate, on each Mod's metadata,
+	// given pointers to Mods and the value of CachedState for each mod
+	DoUpdate([]*Mod, []interface{}) error
 }
 
+// UpdateCheck represents the data returned from CheckUpdate for each mod
+type UpdateCheck struct {
+	// UpdateAvailable is true if an update is available for this mod
+	UpdateAvailable bool
+	// UpdateString is a string that details the update in some way to the user. Usually this will be in the form of
+	// a version change (1.0.0 -> 1.0.1), or a file name change (thanos-skin-1.0.0.jar -> thanos-skin-1.0.1.jar).
+	UpdateString string
+	// CachedState can be used to preserve per-mod state between CheckUpdate and DoUpdate (e.g. file metadata)
+	CachedState interface{}
+	// Error stores an error for this specific mod
+	// Errors can also be returned from CheckUpdate directly, if the whole operation failed completely (so only 1 error is printed)
+	// If an error is returned for a mod, or from CheckUpdate, DoUpdate is not called on that mod / at all
+	Error error
+}
+
+// TODO: new docs
+// to carry out updating:
+
+// go through all metafiles in index
+// make a []Mod for each updater, so map[string][]Mod
+// for each Mod, check the "first" updater, then give the Mod to the map
+
+// go through the map, call CheckUpdate with the []Mod
+// print to user, if interactive mode
+// call doupdate with the mods and interfaces!!