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.

cmd/syncthing/gui.go

@@ -794,7 +794,7 @@ func toNeedSlice(fs []db.FileInfoTruncated) []map[string]interface{} {
 			"Version":      file.Version,
 			"LocalVersion": file.LocalVersion,
 			"NumBlocks":    file.NumBlocks,
-			"Size":         db.BlocksToSize(file.NumBlocks),
+			"Size":         db.BlocksToSize(int(file.NumBlocks)),
 		}
 	}
 	return output

cmd/syncthing/memsize_darwin.go

@@ -22,7 +22,7 @@ import (
 	"strings"
 )
 
-func memorySize() (uint64, error) {
+func memorySize() (int64, error) {
 	cmd := exec.Command("sysctl", "hw.memsize")
 	out, err := cmd.Output()
 	if err != nil {
@@ -32,7 +32,7 @@ func memorySize() (uint64, error) {
 	if len(fs) != 2 {
 		return 0, errors.New("sysctl parse error")
 	}
-	bytes, err := strconv.ParseUint(fs[1], 10, 64)
+	bytes, err := strconv.ParseInt(fs[1], 10, 64)
 	if err != nil {
 		return 0, err
 	}

cmd/syncthing/memsize_linux.go

@@ -23,7 +23,7 @@ import (
 	"strings"
 )
 
-func memorySize() (uint64, error) {
+func memorySize() (int64, error) {
 	f, err := os.Open("/proc/meminfo")
 	if err != nil {
 		return 0, err
@@ -40,7 +40,7 @@ func memorySize() (uint64, error) {
 		return 0, errors.New("/proc/meminfo parse error 2")
 	}
 
-	kb, err := strconv.ParseUint(fs[1], 10, 64)
+	kb, err := strconv.ParseInt(fs[1], 10, 64)
 	if err != nil {
 		return 0, err
 	}

cmd/syncthing/memsize_solaris.go

@@ -22,14 +22,14 @@ import (
 	"strconv"
 )
 
-func memorySize() (uint64, error) {
+func memorySize() (int64, error) {
 	cmd := exec.Command("prtconf", "-m")
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		return 0, err
 	}
 
-	mb, err := strconv.ParseUint(string(out), 10, 64)
+	mb, err := strconv.ParseInt(string(out), 10, 64)
 	if err != nil {
 		return 0, err
 	}

cmd/syncthing/memsize_unimpl.go

@@ -19,6 +19,6 @@ package main
 
 import "errors"
 
-func memorySize() (uint64, error) {
+func memorySize() (int64, error) {
 	return 0, errors.New("not implemented")
 }

cmd/syncthing/memsize_windows.go

@@ -26,7 +26,7 @@ var (
 	globalMemoryStatusEx, _ = syscall.GetProcAddress(kernel32, "GlobalMemoryStatusEx")
 )
 
-func memorySize() (uint64, error) {
+func memorySize() (int64, error) {
 	var memoryStatusEx [64]byte
 	binary.LittleEndian.PutUint32(memoryStatusEx[:], 64)
 	p := uintptr(unsafe.Pointer(&memoryStatusEx[0]))
@@ -36,5 +36,5 @@ func memorySize() (uint64, error) {
 		return 0, callErr
 	}
 
-	return binary.LittleEndian.Uint64(memoryStatusEx[8:]), nil
+	return int64(binary.LittleEndian.Uint64(memoryStatusEx[8:])), nil
 }

cmd/syncthing/perfstats_unix.go

@@ -43,7 +43,7 @@ func savePerfStats(file string) {
 	var prevTime int64
 	var rusage syscall.Rusage
 	var memstats runtime.MemStats
-	var prevIn, prevOut uint64
+	var prevIn, prevOut int64
 
 	t0 := time.Now()
 	for t := range time.NewTicker(250 * time.Millisecond).C {