Improve database to golang name mapping.

internal/3rdparty/snaker/snaker.go

@@ -0,0 +1,192 @@
+package snaker
+
+// Package snaker provides methods to convert CamelCase names to snake_case and back.
+// It considers the list of allowed initialsms used by github.com/golang/lint/golint (e.g. ID or HTTP)
+
+import (
+	"strings"
+	"unicode"
+)
+
+// CamelToSnake converts a given string to snake case
+func CamelToSnake(s string) string {
+	var result string
+	var words []string
+	var lastPos int
+	rs := []rune(s)
+
+	for i := 0; i < len(rs); i++ {
+		if i > 0 && unicode.IsUpper(rs[i]) {
+			if initialism := startsWithInitialism(s[lastPos:]); initialism != "" {
+				words = append(words, initialism)
+
+				i += len(initialism) - 1
+				lastPos = i
+				continue
+			}
+
+			words = append(words, s[lastPos:i])
+			lastPos = i
+		}
+	}
+
+	// append the last word
+	if s[lastPos:] != "" {
+		words = append(words, s[lastPos:])
+	}
+
+	for k, word := range words {
+		if k > 0 {
+			result += "_"
+		}
+
+		result += strings.ToLower(word)
+	}
+
+	return result
+}
+
+func snakeToCamel(s string, upperCase bool) string {
+	if len(s) == 0 {
+		return s
+	}
+	var result string
+
+	words := strings.Split(s, "_")
+
+	//// if there is no underscore, first try commons and then just return
+	//if len(words) == 1 {
+	//	if exception := snakeToCamelExceptions[words[0]]; len(exception) > 0 {
+	//		return exception
+	//	}
+	//
+	//	if upperCase {
+	//		if upper := strings.ToUpper(words[0]); commonInitialisms[upper] {
+	//			return upper
+	//		}
+	//	}
+	//
+	//	w := []rune(s)
+	//	if upperCase {
+	//		w[0] = unicode.ToUpper(w[0])
+	//	} else {
+	//		w[0] = unicode.ToLower(w[0])
+	//	}
+	//
+	//	return string(w)
+	//}
+
+	for i, word := range words {
+		if exception := snakeToCamelExceptions[word]; len(exception) > 0 {
+			result += exception
+			continue
+		}
+
+		if upperCase || i > 0 {
+			if upper := strings.ToUpper(word); commonInitialisms[upper] {
+				result += upper
+				continue
+			}
+		}
+
+		if upperCase || i > 0 {
+			result += camelizeWord(word, len(words) > 1)
+		} else {
+			result += word
+		}
+	}
+
+	return result
+}
+
+func camelizeWord(word string, force bool) string {
+	runes := []rune(word)
+
+	for i, r := range runes {
+		if i == 0 {
+			runes[i] = unicode.ToUpper(r)
+		} else {
+			if !force && unicode.IsLower(r) { // already camelCase
+				return string(runes)
+			}
+
+			runes[i] = unicode.ToLower(r)
+		}
+	}
+
+	return string(runes)
+}
+
+// SnakeToCamel returns a string converted from snake case to uppercase
+func SnakeToCamel(s string) string {
+	return snakeToCamel(s, true)
+}
+
+// SnakeToCamelLower returns a string converted from snake case to lowercase
+func SnakeToCamelLower(s string) string {
+	return snakeToCamel(s, false)
+}
+
+// startsWithInitialism returns the initialism if the given string begins with it
+func startsWithInitialism(s string) string {
+	var initialism string
+	// the longest initialism is 5 char, the shortest 2
+	for i := 1; i <= 5; i++ {
+		if len(s) > i-1 && commonInitialisms[s[:i]] {
+			initialism = s[:i]
+		}
+	}
+	return initialism
+}
+
+// commonInitialisms, taken from
+// https://github.com/golang/lint/blob/206c0f020eba0f7fbcfbc467a5eb808037df2ed6/lint.go#L731
+var commonInitialisms = map[string]bool{
+	"ACL":   true,
+	"API":   true,
+	"ASCII": true,
+	"CPU":   true,
+	"CSS":   true,
+	"DNS":   true,
+	"EOF":   true,
+	"ETA":   true,
+	"GPU":   true,
+	"GUID":  true,
+	"HTML":  true,
+	"HTTP":  true,
+	"HTTPS": true,
+	"ID":    true,
+	"IP":    true,
+	"JSON":  true,
+	"LHS":   true,
+	"OS":    true,
+	"QPS":   true,
+	"RAM":   true,
+	"RHS":   true,
+	"RPC":   true,
+	"SLA":   true,
+	"SMTP":  true,
+	"SQL":   true,
+	"SSH":   true,
+	"TCP":   true,
+	"TLS":   true,
+	"TTL":   true,
+	"UDP":   true,
+	"UI":    true,
+	"UID":   true,
+	"UUID":  true,
+	"URI":   true,
+	"URL":   true,
+	"UTF8":  true,
+	"VM":    true,
+	"XML":   true,
+	"XMPP":  true,
+	"XSRF":  true,
+	"XSS":   true,
+	"OAuth": true,
+}
+
+// add exceptions here for things that are not automatically convertable
+var snakeToCamelExceptions = map[string]string{
+	"oauth": "OAuth",
+}