Blame support for files

This also includes a diff package and revlist package (needed by
blame)

Some extra packfiles (<1MB) are also included, to be used as fixtures in
the tests.

1 files changed, 49 insertions, 0 deletions

diff --git a/common.go b/common.go
new file mode 100644
index 0000000..3e25fc7
--- /dev/null
+++ b/common.go
@@ -0,0 +1,49 @@
+package git
+
+import (
+	"bytes"
+	"strings"
+)
+
+// CountLines returns the number of lines in a string.
+// The newline character is assumed to be '\n'.
+// The empty string contains 0 lines.
+// If the last line of the string doesn't end with a newline, it will
+// still be considered a line.
+func CountLines(s string) int {
+	if s == "" {
+		return 0
+	}
+	nEol := strings.Count(s, "\n")
+	if strings.HasSuffix(s, "\n") {
+		return nEol
+	}
+	return nEol + 1
+}
+
+// FindFile searches for a path in a commit. Returns the file and true if found.
+// Returns nil and false if not found.
+// TODO: should this be a method of git.Commit instead?
+func FindFile(path string, commit *Commit) (file *File, found bool) {
+	tree := commit.Tree()
+	for file := range tree.Files() {
+		if file.Name == path {
+			return file, true
+		}
+	}
+	return nil, false
+}
+
+// Data returns the contents of a file in a commit and true if found.
+// Returns an empty string and false if the file is not found in the
+// commit.
+// TODO: should this be a method of git.Commit instead?
+func Data(path string, commit *Commit) (contents string, found bool) {
+	file, found := FindFile(path, commit)
+	if !found {
+		return "", found
+	}
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(file)
+	return buf.String(), found
+}