Merge pull request #18 from yazgazan/structs

Supporting structs

.travis.yml

@@ -1,8 +1,8 @@
 language: go
 go:
     - "1.10"
-    - 1.11
-    - 1.12
+    - "1.11"
+    - "1.12"
 
 before_install:
     - go get -u golang.org/x/tools/cmd/cover

Readme.md

@@ -8,21 +8,21 @@
 
 A JSON diff utility.
 
-# Install
+## Install
 
-## Downloading the compiled binary
+### Downloading the compiled binary
 
 - Download the latest version of the binary: [releases](https://github.com/yazgazan/jaydiff/releases)
 - extract the archive and place the `jaydiff` binary in your `$PATH`
 
-## From source
+### From source
 
 - Have go 1.10 or greater installed: [golang.org](https://golang.org/doc/install)
 - run `go get -u github.com/yazgazan/jaydiff`
 
-# Usage
+## Usage
 
-```
+```text
 Usage:
   jaydiff [OPTIONS] FILE_1 FILE_2
 
@@ -41,7 +41,7 @@ Help Options:
   -h, --help           Show this help message
 ```
 
-## Examples
+### Examples
 
 Getting a full diff of two json files:
 
@@ -73,8 +73,8 @@ Ignoring fields:
 
 ```diff
 $ jaydiff --show-types \
-	  --ignore='.b\[\]' --ignore='.d' --ignore='.c.[ac]' \
-	    old.json new.json
+    --ignore='.b\[\]' --ignore='.d' --ignore='.c.[ac]' \
+      old.json new.json
 
  map[string]interface {} map[
      a: float64 42
@@ -159,9 +159,8 @@ $ jaydiff --report --show-types --ignore-excess --ignore-values old.json new.jso
 - .f: float64 42
 ```
 
-# Ideas
+## Ideas
 
 - JayPatch
-- Have the diff lib support more types (Structs, interfaces (?), Arrays, ...)
 
 Sponsored by [Datumprikker.nl](https://datumprikker.nl)

diff/diff.go

@@ -43,8 +43,8 @@ func Diff(lhs, rhs interface{}, opts ...ConfigOpt) (Differ, error) {
 }
 
 func diff(c config, lhs, rhs interface{}, visited *visited) (Differ, error) {
-	lhsVal := reflect.ValueOf(lhs)
-	rhsVal := reflect.ValueOf(rhs)
+	lhsVal, lhs := indirectValueOf(lhs)
+	rhsVal, rhs := indirectValueOf(rhs)
 
 	if d, ok := nilCheck(lhs, rhs); ok {
 		return d, nil
@@ -56,23 +56,43 @@ func diff(c config, lhs, rhs interface{}, visited *visited) (Differ, error) {
 		return types{lhs, rhs}, ErrCyclic
 	}
 
-	if lhsVal.Type().Comparable() && rhsVal.Type().Comparable() {
+	if valueIsScalar(lhsVal) && valueIsScalar(rhsVal) {
 		return scalar{lhs, rhs}, nil
 	}
 	if lhsVal.Kind() != rhsVal.Kind() {
 		return types{lhs, rhs}, nil
 	}
 
-	if lhsVal.Kind() == reflect.Slice {
+	switch lhsVal.Kind() {
+	case reflect.Slice, reflect.Array:
 		return c.sliceFn(c, lhs, rhs, visited)
-	}
-	if lhsVal.Kind() == reflect.Map {
+	case reflect.Map:
 		return newMap(c, lhs, rhs, visited)
+	case reflect.Struct:
+		return newStruct(c, lhs, rhs, visited)
 	}
 
 	return types{lhs, rhs}, &ErrUnsupported{lhsVal.Type(), rhsVal.Type()}
 }
 
+func indirectValueOf(i interface{}) (reflect.Value, interface{}) {
+	v := reflect.Indirect(reflect.ValueOf(i))
+	if !v.IsValid() || !v.CanInterface() {
+		return reflect.ValueOf(i), i
+	}
+
+	return v, v.Interface()
+}
+
+func valueIsScalar(v reflect.Value) bool {
+	switch v.Kind() {
+	default:
+		return v.Type().Comparable()
+	case reflect.Struct, reflect.Array, reflect.Ptr, reflect.Chan:
+		return false
+	}
+}
+
 func nilCheck(lhs, rhs interface{}) (Differ, bool) {
 	if lhs == nil && rhs == nil {
 		return scalar{lhs, rhs}, true