thodg/libgit2

diff --git a/include/git2/blame.h b/include/git2/blame.h
index 34cb699..cc91317 100644
--- a/include/git2/blame.h
+++ b/include/git2/blame.h
@@ -43,6 +43,10 @@ typedef enum {
 	/** Restrict the search of commits to those reachable following only the
 	 * first parents. */
 	GIT_BLAME_FIRST_PARENT = (1<<4),
+	/** Use mailmap file to map author and committer names and email addresses
+	 * to canonical real names and email addresses. The mailmap will be read
+	 * from the working directory, or HEAD in a bare repository. */
+	GIT_BLAME_USE_MAILMAP = (1<<5),
 } git_blame_flag_t;
 
 /**
@@ -108,6 +112,9 @@ GIT_EXTERN(int) git_blame_init_options(
  *   changed.
  * - `final_start_line_number` is the 1-based line number where this hunk
  *   begins, in the final version of the file
+ * - `final_signature` is the author of `final_commit_id`. If
+ *   `GIT_BLAME_USE_MAILMAP` has been specified, it will contain the canonical
+ *    real name and email address.
  * - `orig_commit_id` is the OID of the commit where this hunk was found.  This
  *   will usually be the same as `final_commit_id`, except when
  *   `GIT_BLAME_TRACK_COPIES_ANY_COMMIT_COPIES` has been specified.
@@ -116,6 +123,9 @@ GIT_EXTERN(int) git_blame_init_options(
  * - `orig_start_line_number` is the 1-based line number where this hunk begins
  *   in the file named by `orig_path` in the commit specified by
  *   `orig_commit_id`.
+ * - `orig_signature` is the author of `orig_commit_id`. If
+ *   `GIT_BLAME_USE_MAILMAP` has been specified, it will contain the canonical
+ *    real name and email address.
  * - `boundary` is 1 iff the hunk has been tracked to a boundary commit (the
  *   root, or the commit specified in git_blame_options.oldest_commit)
  */
diff --git a/include/git2/commit.h b/include/git2/commit.h
index 692b3bd..50f2fc9 100644
--- a/include/git2/commit.h
+++ b/include/git2/commit.h
@@ -173,6 +173,34 @@ GIT_EXTERN(const git_signature *) git_commit_committer(const git_commit *commit)
 GIT_EXTERN(const git_signature *) git_commit_author(const git_commit *commit);
 
 /**
+ * Get the committer of a commit, using the mailmap to map names and email
+ * addresses to canonical real names and email addresses.
+ *
+ * Call `git_signature_free` to free the signature.
+ *
+ * @param out a pointer to store the resolved signature.
+ * @param commit a previously loaded commit.
+ * @param mailmap the mailmap to resolve with. (may be NULL)
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_commit_committer_with_mailmap(
+	git_signature **out, const git_commit *commit, const git_mailmap *mailmap);
+
+/**
+ * Get the author of a commit, using the mailmap to map names and email
+ * addresses to canonical real names and email addresses.
+ *
+ * Call `git_signature_free` to free the signature.
+ *
+ * @param out a pointer to store the resolved signature.
+ * @param commit a previously loaded commit.
+ * @param mailmap the mailmap to resolve with. (may be NULL)
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_commit_author_with_mailmap(
+	git_signature **out, const git_commit *commit, const git_mailmap *mailmap);
+
+/**
  * Get the full raw text of the commit header.
  *
  * @param commit a previously loaded commit
diff --git a/include/git2/signature.h b/include/git2/signature.h
index 7a2a023..18fae98 100644
--- a/include/git2/signature.h
+++ b/include/git2/signature.h
@@ -76,6 +76,19 @@ GIT_EXTERN(int) git_signature_default(git_signature **out, git_repository *repo)
 GIT_EXTERN(int) git_signature_from_buffer(git_signature **out, const char *buf);
 
 /**
+ * Create a signature with names updated respecting the mailmap.
+ *
+ * Call `git_signature_free()` to free the data.
+ *
+ * @param out new signature
+ * @param sig signature to resolve
+ * @param mailmap mailmap to resolve with
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_signature_with_mailmap(
+  git_signature **out, const git_signature *sig, const git_mailmap *mailmap);
+
+/**
  * Create a copy of an existing signature.  All internal strings are also
  * duplicated.
  *
diff --git a/include/git2/types.h b/include/git2/types.h
index 67e5bd1..943a7e9 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -434,6 +434,9 @@ struct git_writestream {
 	void (*free)(git_writestream *stream);
 };
 
+/** A parsed representation of a .mailmap file. */
+typedef struct git_mailmap git_mailmap;
+
 /** @} */
 GIT_END_DECL
 
diff --git a/src/blame.c b/src/blame.c
index a923bf0..967530b 100644
--- a/src/blame.c
+++ b/src/blame.c
@@ -132,6 +132,9 @@ git_blame* git_blame__alloc(
 		return NULL;
 	}
 
+	if (opts.flags & GIT_BLAME_USE_MAILMAP)
+		git_mailmap_from_repo(&gbr->mailmap, repo);
+
 	return gbr;
 }
 
@@ -150,6 +153,8 @@ void git_blame_free(git_blame *blame)
 
 	git_array_clear(blame->line_index);
 
+	git_mailmap_free(blame->mailmap);
+
 	git__free(blame->path);
 	git_blob_free(blame->final_blob);
 	git__free(blame);
@@ -279,7 +284,7 @@ static int index_blob_lines(git_blame *blame)
     return blame->num_lines;
 }
 
-static git_blame_hunk* hunk_from_entry(git_blame__entry *e)
+static git_blame_hunk* hunk_from_entry(git_blame__entry *e, git_blame *blame)
 {
 	git_blame_hunk *h = new_hunk(
 			e->lno+1, e->num_lines, e->s_lno+1, e->suspect->path);
@@ -289,8 +294,9 @@ static git_blame_hunk* hunk_from_entry(git_blame__entry *e)
 
 	git_oid_cpy(&h->final_commit_id, git_commit_id(e->suspect->commit));
 	git_oid_cpy(&h->orig_commit_id, git_commit_id(e->suspect->commit));
-	git_signature_dup(&h->final_signature, git_commit_author(e->suspect->commit));
-	git_signature_dup(&h->orig_signature, git_commit_author(e->suspect->commit));
+	git_commit_author_with_mailmap(
+		&h->final_signature, e->suspect->commit, blame->mailmap);
+	git_signature_dup(&h->orig_signature, h->final_signature);
 	h->boundary = e->is_boundary ? 1 : 0;
 	return h;
 }
@@ -341,7 +347,7 @@ static int blame_internal(git_blame *blame)
 cleanup:
 	for (ent = blame->ent; ent; ) {
 		git_blame__entry *e = ent->next;
-		git_blame_hunk *h = hunk_from_entry(ent);
+		git_blame_hunk *h = hunk_from_entry(ent, blame);
 
 		git_vector_insert(&blame->hunks, h);
 
diff --git a/src/blame.h b/src/blame.h
index 8fd3ee5..0574132 100644
--- a/src/blame.h
+++ b/src/blame.h
@@ -84,6 +84,8 @@ struct git_blame {
 	int num_lines;
 	const char *final_buf;
 	git_off_t final_buf_size;
+
+	git_mailmap *mailmap;
 };
 
 git_blame *git_blame__alloc(
diff --git a/src/commit.c b/src/commit.c
index e0c090a..03ecea8 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -889,3 +889,15 @@ cleanup:
 	git_buf_dispose(&commit);
 	return error;
 }
+
+int git_commit_committer_with_mailmap(
+	git_signature **out, const git_commit *commit, const git_mailmap *mailmap)
+{
+	return git_signature_with_mailmap(out, commit->committer, mailmap);
+}
+
+int git_commit_author_with_mailmap(
+	git_signature **out, const git_commit *commit, const git_mailmap *mailmap)
+{
+	return git_signature_with_mailmap(out, commit->author, mailmap);
+}
diff --git a/src/signature.c b/src/signature.c
index cd68523..a93ba10 100644
--- a/src/signature.c
+++ b/src/signature.c
@@ -9,6 +9,7 @@
 
 #include "repository.h"
 #include "git2/common.h"
+#include "git2/mailmap.h"
 #include "posix.h"
 
 void git_signature_free(git_signature *sig)
@@ -121,6 +122,44 @@ int git_signature_dup(git_signature **dest, const git_signature *source)
 	return 0;
 }
 
+int git_signature_with_mailmap(
+	git_signature **dest,
+	const git_signature *source,
+	const git_mailmap *mailmap)
+{
+	git_signature *signature = NULL;
+	const char *name = NULL;
+	const char *email = NULL;
+
+	if (source == NULL)
+		goto on_error;
+
+	git_mailmap_resolve(&name, &email, mailmap, source->name, source->email);
+
+	signature = git__calloc(1, sizeof(git_signature));
+	if (!signature)
+		goto on_error;
+
+	signature->name = git__strdup(name);
+	if (!signature->name)
+		goto on_error;
+
+	signature->email = git__strdup(email);
+	if (!signature->email)
+		goto on_error;
+
+	signature->when.time = source->when.time;
+	signature->when.offset = source->when.offset;
+	signature->when.sign = source->when.sign;
+
+	*dest = signature;
+	return 0;
+
+on_error:
+	git_signature_free(signature);
+	return -1;
+}
+
 int git_signature__pdup(git_signature **dest, const git_signature *source, git_pool *pool)
 {
 	git_signature *signature;