plumbing: format/gitattributes support

Implements gitattributes parsing, matching and attribute extraction.

Signed-off-by: Arran Walker <arran.walker@fiveturns.org>

1 files changed, 126 insertions, 0 deletions

diff --git a/plumbing/format/gitattributes/dir.go b/plumbing/format/gitattributes/dir.go
new file mode 100644
index 0000000..d5c1e6a
--- /dev/null
+++ b/plumbing/format/gitattributes/dir.go
@@ -0,0 +1,126 @@
+package gitattributes
+
+import (
+	"os"
+	"os/user"
+
+	"gopkg.in/src-d/go-billy.v4"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/config"
+	gioutil "gopkg.in/src-d/go-git.v4/utils/ioutil"
+)
+
+const (
+	coreSection       = "core"
+	attributesfile    = "attributesfile"
+	gitDir            = ".git"
+	gitattributesFile = ".gitattributes"
+	gitconfigFile     = ".gitconfig"
+	systemFile        = "/etc/gitconfig"
+)
+
+func ReadAttributesFile(fs billy.Filesystem, path []string, attributesFile string, allowMacro bool) ([]MatchAttribute, error) {
+	f, err := fs.Open(fs.Join(append(path, attributesFile)...))
+	if os.IsNotExist(err) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return ReadAttributes(f, path, allowMacro)
+}
+
+// ReadPatterns reads gitattributes patterns recursively through the directory
+// structure. The result is in ascending order of priority (last higher).
+//
+// The .gitattribute file in the root directory will allow custom macro
+// definitions. Custom macro definitions in other directories .gitattributes
+// will return an error.
+func ReadPatterns(fs billy.Filesystem, path []string) (attributes []MatchAttribute, err error) {
+	attributes, err = ReadAttributesFile(fs, path, gitattributesFile, true)
+	if err != nil {
+		return
+	}
+
+	attrs, err := walkDirectory(fs, path)
+	return append(attributes, attrs...), err
+}
+
+func walkDirectory(fs billy.Filesystem, root []string) (attributes []MatchAttribute, err error) {
+	fis, err := fs.ReadDir(fs.Join(root...))
+	if err != nil {
+		return attributes, err
+	}
+
+	for _, fi := range fis {
+		if !fi.IsDir() || fi.Name() == ".git" {
+			continue
+		}
+
+		path := append(root, fi.Name())
+
+		dirAttributes, err := ReadAttributesFile(fs, path, gitattributesFile, false)
+		if err != nil {
+			return attributes, err
+		}
+
+		subAttributes, err := walkDirectory(fs, path)
+		if err != nil {
+			return attributes, err
+		}
+
+		attributes = append(attributes, append(dirAttributes, subAttributes...)...)
+	}
+
+	return
+}
+
+func loadPatterns(fs billy.Filesystem, path string) ([]MatchAttribute, error) {
+	f, err := fs.Open(path)
+	if os.IsNotExist(err) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	defer gioutil.CheckClose(f, &err)
+
+	raw := config.New()
+	if err = config.NewDecoder(f).Decode(raw); err != nil {
+		return nil, nil
+	}
+
+	path = raw.Section(coreSection).Options.Get(attributesfile)
+	if path == "" {
+		return nil, nil
+	}
+
+	return ReadAttributesFile(fs, nil, path, true)
+}
+
+// LoadGlobalPatterns loads gitattributes patterns and attributes from the
+// gitattributes file declared in a user's ~/.gitconfig file.  If the
+// ~/.gitconfig file does not exist the function will return nil. If the
+// core.attributesFile property is not declared, the function will return nil.
+// If the file pointed to by the core.attributesfile property does not exist,
+// the function will return nil. The function assumes fs is rooted at the root
+// filesystem.
+func LoadGlobalPatterns(fs billy.Filesystem) (attributes []MatchAttribute, err error) {
+	usr, err := user.Current()
+	if err != nil {
+		return
+	}
+
+	return loadPatterns(fs, fs.Join(usr.HomeDir, gitconfigFile))
+}
+
+// LoadSystemPatterns loads gitattributes patterns and attributes from the
+// gitattributes file declared in a system's /etc/gitconfig file.  If the
+// /etc/gitconfig file does not exist the function will return nil. If the
+// core.attributesfile property is not declared, the function will return nil.
+// If the file pointed to by the core.attributesfile property does not exist,
+// the function will return nil. The function assumes fs is rooted at the root
+// filesystem.
+func LoadSystemPatterns(fs billy.Filesystem) (attributes []MatchAttribute, err error) {
+	return loadPatterns(fs, systemFile)
+}