Initial commit

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

git/commits.go

@@ -0,0 +1,105 @@
+package git
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+// Commits returns a set of commits.
+// If commitrange is a git still range 12345...54321, then it will be isolated set of commits.
+// If commitrange is a single commit, all ancestor commits up through the hash provided.
+func Commits(commitrange string) ([]CommitEntry, error) {
+	output, err := exec.Command("git", "log", prettyFormat+formatCommit, commitrange).Output()
+	if err != nil {
+		return nil, err
+	}
+	commitHashes := strings.Split(strings.TrimSpace(string(output)), "\n")
+	commits := make([]CommitEntry, len(commitHashes))
+	for i, commitHash := range commitHashes {
+		c, err := LogCommit(commitHash)
+		if err != nil {
+			return commits, err
+		}
+		commits[i] = *c
+	}
+	return commits, nil
+}
+
+// CommitEntry represents a single commit's information from `git`
+type CommitEntry map[string]string
+
+var (
+	prettyFormat         = `--pretty=format:`
+	formatSubject        = `%s`
+	formatBody           = `%b`
+	formatCommit         = `%H`
+	formatAuthorName     = `%aN`
+	formatAuthorEmail    = `%aE`
+	formatCommitterName  = `%cN`
+	formatCommitterEmail = `%cE`
+	formatSigner         = `%GS`
+	formatCommitNotes    = `%N`
+	formatMap            = `{"commit": "%H", "abbreviated_commit": "%h", "tree": "%T", "abbreviated_tree": "%t", "parent": "%P", "abbreviated_parent": "%p", "refs": "%D", "encoding": "%e", "sanitized_subject_line": "%f", "verification_flag": "%G?", "signer_key": "%GK", "author_date": "%aD" , "committer_date": "%cD" }`
+)
+
+// LogCommit assembles the full information on a commit from its commit hash
+func LogCommit(commit string) (*CommitEntry, error) {
+	buf := bytes.NewBuffer([]byte{})
+	cmd := exec.Command("git", "log", "-1", prettyFormat+formatMap, commit)
+	cmd.Stdout = buf
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Run(); err != nil {
+		log.Println(strings.Join(cmd.Args, " "))
+		return nil, err
+	}
+	c := CommitEntry{}
+	output := buf.Bytes()
+	if err := json.Unmarshal(output, &c); err != nil {
+		fmt.Println(string(output))
+		return nil, err
+	}
+
+	// any user provided fields can't be sanitized for the mock-json marshal above
+	for k, v := range map[string]string{
+		"subject":         formatSubject,
+		"body":            formatBody,
+		"author_name":     formatAuthorName,
+		"author_email":    formatAuthorEmail,
+		"committer_name":  formatCommitterName,
+		"committer_email": formatCommitterEmail,
+		"commit_notes":    formatCommitNotes,
+		"signer":          formatSigner,
+	} {
+		output, err := exec.Command("git", "log", "-1", prettyFormat+v, commit).Output()
+		if err != nil {
+			return nil, err
+		}
+		c[k] = strings.TrimSpace(string(output))
+	}
+
+	return &c, nil
+}
+
+// FetchHeadCommit returns the hash of FETCH_HEAD
+func FetchHeadCommit() (string, error) {
+	output, err := exec.Command("git", "rev-parse", "--verify", "FETCH_HEAD").Output()
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(string(output)), nil
+}
+
+// HeadCommit returns the hash of HEAD
+func HeadCommit() (string, error) {
+	output, err := exec.Command("git", "rev-parse", "--verify", "HEAD").Output()
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(string(output)), nil
+}