From 2a8ad5689c8f810902dce3fc3e7d849f5e89bf12 Mon Sep 17 00:00:00 2001
From: Amy Boyd <amy@amyboyd.co.uk>
Date: Wed, 22 Jun 2016 23:58:10 +0100
Subject: [PATCH] Add function GetRulesToApplyToSourcePath.

---
 editorconfig/apply.go            | 73 ++++++++++++++++++++++++++++++++
 editorconfig/apply_test.go       | 34 +++++++++++++++
 editorconfig/config_file.go      |  5 ++-
 editorconfig/tests/.editorconfig |  3 ++
 4 files changed, 114 insertions(+), 1 deletion(-)
 create mode 100644 editorconfig/apply.go
 create mode 100644 editorconfig/apply_test.go

diff --git a/editorconfig/apply.go b/editorconfig/apply.go
new file mode 100644
index 0000000..b96d165
--- /dev/null
+++ b/editorconfig/apply.go
@@ -0,0 +1,73 @@
+package editorconfig
+
+import (
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+func GetRulesToApplyToSourcePath(sourcePath string, cfs []ConfigFile) map[string]string {
+	applicable := FilterConfigFilesToApplyToSourcePath(sourcePath, cfs)
+	applicableSorted := SortConfigFilesByPrecendence(applicable)
+
+	rules := make(map[string]string)
+
+	for _, cf := range applicableSorted {
+		for _, rule := range cf.DefaultRuleSet {
+			rules[rule.Name] = rule.Value
+		}
+
+		for _, rs := range cf.FileConstrainedRuleSets {
+			if rs.ConstraintRegexp.MatchString(sourcePath) {
+				for _, rule := range rs.Rules {
+					rules[rule.Name] = rule.Value
+				}
+			}
+		}
+	}
+
+	delete(rules, "root")
+
+	return rules
+}
+
+func FilterConfigFilesToApplyToSourcePath(sourcePath string, cfs []ConfigFile) []ConfigFile {
+	applicable := []ConfigFile{}
+
+	for _, cf := range cfs {
+		absSourcePath, err := filepath.Abs(sourcePath)
+		if err != nil {
+			ExitBecauseOfInternalError("Could not get absolute path for " + sourcePath)
+		}
+		absCfDir, err := filepath.Abs(cf.Dir())
+		if err != nil {
+			ExitBecauseOfInternalError("Could not get absolute path for " + cf.Dir())
+		}
+		if strings.HasPrefix(absSourcePath, absCfDir) {
+			applicable = append(applicable, cf)
+		}
+	}
+
+	return applicable
+}
+
+// ByPrecedence implements sort.Interface for []ConfigFile based on how many slashes are in the file's path.
+type ByPrecedence []ConfigFile
+
+func (a ByPrecedence) Len() int {
+	return len(a)
+}
+func (a ByPrecedence) Swap(i, j int) {
+	a[i], a[j] = a[j], a[i]
+}
+func (a ByPrecedence) Less(i, j int) bool {
+	return a[i].Precedence() < a[j].Precedence()
+}
+
+/**
+ * @return Least important files first, most important files last.
+ */
+func SortConfigFilesByPrecendence(cfs []ConfigFile) []ConfigFile {
+	sort.Sort(ByPrecedence(cfs))
+	return cfs
+}
diff --git a/editorconfig/apply_test.go b/editorconfig/apply_test.go
new file mode 100644
index 0000000..593e7cd
--- /dev/null
+++ b/editorconfig/apply_test.go
@@ -0,0 +1,34 @@
+package editorconfig
+
+import (
+	"testing"
+)
+
+func TestGetRulesToApplyToSourcePath(t *testing.T) {
+	result := GetRulesToApplyToSourcePath(
+		"tests/a/b/file.go",
+		[]ConfigFile{
+			CreateConfigFileStruct("tests/.editorconfig"),
+		},
+	)
+
+	if result["end_of_line"] != "lf" {
+		t.Error("The end_of_line rule should come from the * file pattern")
+	}
+	if result["indent_style"] != "tabs" {
+		t.Error("The indent_style rule should come from the **.go file pattern, overriding the *'s indent_style")
+	}
+}
+
+func TestGetRulesToApplyToSourcePathWhenNoRulesShouldApply(t *testing.T) {
+	result := GetRulesToApplyToSourcePath(
+		"some-file-not-affected-by-rules",
+		[]ConfigFile{
+			CreateConfigFileStruct("tests/.editorconfig"),
+		},
+	)
+
+	if len(result) != 0 {
+		t.Error("No rules should be applied for the file")
+	}
+}
diff --git a/editorconfig/config_file.go b/editorconfig/config_file.go
index ee56c14..2d4dde7 100644
--- a/editorconfig/config_file.go
+++ b/editorconfig/config_file.go
@@ -2,6 +2,7 @@ package editorconfig
 
 import (
 	"github.com/go-ini/ini"
+	"path/filepath"
 	"regexp"
 	"strings"
 )
@@ -51,9 +52,11 @@ type FileConstrainedRuleSet struct {
 }
 
 func CreateConfigFileStruct(path string) ConfigFile {
+	absPath, _ := filepath.Abs(path)
+
 	ini, err := ini.Load(path)
 	if err != nil {
-		ExitBecauseOfInternalError("Could not parse " + path)
+		ExitBecauseOfInternalError("Could not parse " + absPath)
 	}
 
 	cf := ConfigFile{}
diff --git a/editorconfig/tests/.editorconfig b/editorconfig/tests/.editorconfig
index 7e9d9b5..36c6853 100644
--- a/editorconfig/tests/.editorconfig
+++ b/editorconfig/tests/.editorconfig
@@ -10,3 +10,6 @@ insert_final_newline = true
 
 [keep-trailing-spaces]
 trim_trailing_whitespace = false
+
+[**.go]
+indent_style = tabs