Integer type policy

Integers are for numbers, enabling arithmetic like subtractions and for
loops without getting shot in the foot. Unsigneds are for bitfields.

- "int" for numbers that will always be laughably smaller than four
  billion, and where we don't care about the serialization format.

- "int32" for numbers that will always be laughably smaller than four
  billion, and will be serialized to four bytes.

- "int64" for numbers that may approach four billion or will be
  serialized to eight bytes.

- "uint32" and "uint64" for bitfields, depending on required number of
  bits and serialization format. Likewise "uint8" and "uint16", although
  rare in this project since they don't exist in XDR.

- "int8", "int16" and plain "uint" are almost never useful.

internal/db/blockmap.go

@@ -160,7 +160,7 @@ func (f *BlockFinder) Changed(cfg config.Configuration) error {
 // the block) or false to continue iterating for whatever reason.
 // The iterator finally returns the result, whether or not a satisfying block
 // was eventually found.
-func (f *BlockFinder) Iterate(hash []byte, iterFn func(string, string, uint32) bool) bool {
+func (f *BlockFinder) Iterate(hash []byte, iterFn func(string, string, int32) bool) bool {
 	f.mut.RLock()
 	folders := f.folders
 	f.mut.RUnlock()
@@ -171,7 +171,7 @@ func (f *BlockFinder) Iterate(hash []byte, iterFn func(string, string, uint32) b
 
 		for iter.Next() && iter.Error() == nil {
 			folder, file := fromBlockKey(iter.Key())
-			index := binary.BigEndian.Uint32(iter.Value())
+			index := int32(binary.BigEndian.Uint32(iter.Value()))
 			if iterFn(folder, osutil.NativeFilename(file), index) {
 				return true
 			}
@@ -182,7 +182,7 @@ func (f *BlockFinder) Iterate(hash []byte, iterFn func(string, string, uint32) b
 
 // A method for repairing incorrect blockmap entries, removes the old entry
 // and replaces it with a new entry for the given block
-func (f *BlockFinder) Fix(folder, file string, index uint32, oldHash, newHash []byte) error {
+func (f *BlockFinder) Fix(folder, file string, index int32, oldHash, newHash []byte) error {
 	buf := make([]byte, 4)
 	binary.BigEndian.PutUint32(buf, uint32(index))