thodg/libgit2

diff --git a/include/git2/mailmap.h b/include/git2/mailmap.h
index a8c4ccb..761db67 100644
--- a/include/git2/mailmap.h
+++ b/include/git2/mailmap.h
@@ -21,103 +21,93 @@
 GIT_BEGIN_DECL
 
 /**
- * A single entry parsed from a mailmap.
- */
-typedef struct git_mailmap_entry {
-	unsigned int version;
-
-	const char *real_name; /**< the real name (may be NULL) */
-	const char *real_email; /**< the real email (may be NULL) */
-	const char *replace_name; /**< the name to replace (may be NULL) */
-	const char *replace_email; /**< the email to replace */
-} git_mailmap_entry;
-
-#define GIT_MAILMAP_ENTRY_VERSION 1
-#define GIT_MAILMAP_ENTRY_INIT {GIT_MAILMAP_ENTRY_VERSION}
-
-/**
- * Create a mailmap object by parsing a mailmap file. Malformed entries in the
- * mailmap are ignored.
+ * Allocate a new mailmap object.
  *
- * The mailmap must be freed with 'git_mailmap_free'.
+ * This object is empty, so you'll have to add a mailmap file before you can do
+ * anything with it. The mailmap must be freed with 'git_mailmap_free'.
  *
- * @param out pointer to store the mailmap
- * @param buffer buffer to parse the mailmap from
- * @return 0 on success, otherwise an error code
+ * @param out pointer to store the new mailmap
+ * @return 0 on success, or an error code
  */
-GIT_EXTERN(int) git_mailmap_from_buffer(git_mailmap **out, git_buf *buffer);
+GIT_EXTERN(int) git_mailmap_new(git_mailmap **out);
 
 /**
- * Create a mailmap object from the given repository. Malformed entries in the
- * mailmap are ignored.
- *
- * If the repository is not bare, the repository's working directory root will
- * be checked for the '.mailmap' file to be parsed.
- *
- * If the repository is bare, the repository's HEAD commit's tree root will be
- * searched for the '.mailmap' file to be parsed.
- *
- * The mailmap must be freed with 'git_mailmap_free'.
+ * Free the mailmap and its associated memory.
  *
- * @param out pointer to store the mailmap
- * @param repo repository to find the .mailmap in
- * @return 0 on success; GIT_ENOTFOUND if .mailmap could not be found,
- *         otherwise an error code.
+ * @param mm the mailmap to free
  */
-GIT_EXTERN(int) git_mailmap_from_repo(git_mailmap **out, git_repository *repo);
+GIT_EXTERN(void) git_mailmap_free(git_mailmap *mm);
 
 /**
- * Free a mailmap created by 'git_mailmap_from_buffer' or
- * 'git_mailmap_from_repo'.
+ * Add a single entry to the given mailmap object. If the entry already exists,
+ * it will be replaced with the new entry.
+ *
+ * @param mm mailmap to add the entry to
+ * @param real_name the real name to use, or NULL
+ * @param real_email the real email to use, or NULL
+ * @param replace_name the name to replace, or NULL
+ * @param replace_email the email to replace
+ * @return 0 if it was added, EEXISTS if it replaced an entry, or an error code
  */
-GIT_EXTERN(void) git_mailmap_free(git_mailmap *mailmap);
+GIT_EXTERN(int) git_mailmap_add_entry(
+	git_mailmap *mm, const char *real_name, const char *real_email,
+	const char *replace_name, const char *replace_email);
 
 /**
- * Resolve a name and email to the corresponding real name and email.
+ * Parse mailmap entries from a buffer.
  *
- * The lifetime of the string results is tied to the `mailmap`, `name`, and
- * `email` parameters.
- *
- * @param name_out either 'name', or the real name to use.
- *             You should NOT free this value.
- * @param email_out either 'email' or the real email to use,
- *             You should NOT free this value.
- * @param mailmap the mailmap to perform the lookup in. (may be NULL)
- * @param name the name to resolve.
- * @param email the email to resolve.
- * @return 0 on success, otherwise an error code.
+ * @param mm mailmap to add the entries to
+ * @param buf the buffer to read the mailmap file from
+ * @return 0 on success, or an error code
  */
-GIT_EXTERN(int) git_mailmap_resolve(
-	const char **name_out, const char **email_out,
-	const git_mailmap *mailmap, const char *name, const char *email);
+GIT_EXTERN(int) git_mailmap_add_buffer(git_mailmap *mm, const git_buf *buf);
 
 /**
- * Get the number of mailmap entries in this mailmap.
+ * Create a new mailmap instance containing a single mailmap file
+ *
+ * This method is a simple utility wrapper for the following sequence
+ * of calls:
+ *  - git_mailmap_new
+ *  - git_mailmap_add_buffer
+ *
+ * @param out pointer to store the new mailmap
+ * @param buf buffer to parse the mailmap from
+ * @return 0 on success, or an error code
  */
-GIT_EXTERN(size_t) git_mailmap_entry_count(const git_mailmap *mailmap);
+GIT_EXTERN(int) git_mailmap_from_buffer(git_mailmap **out, const git_buf *buf);
 
 /**
- * Lookup a mailmap entry by index.
+ * Create a new mailmap instance from a repository, loading mailmap files based
+ * on the repository's configuration.
  *
- * Do not free the mailmap entry, it is owned by the mailmap.
+ * Mailmaps are loaded in the following order:
+ *  1. '.mailmap' in the root of the repository's working directory, if present.
+ *  2. The blob object identified by the 'mailmap.blob' config entry, if set.
+ * 	   [NOTE: 'mailmap.blob' defaults to 'HEAD:.mailmap' in bare repositories]
+ *  3. The path in the 'mailmap.file' config entry, if set.
  *
- * @return the mailmap entry at index, or NULL if it cannot be found.
+ * @param out pointer to store the new mailmap
+ * @param repo repository to load mailmap information from
+ * @return 0 on success, or an error code
  */
-GIT_EXTERN(const git_mailmap_entry *) git_mailmap_entry_byindex(
-	const git_mailmap *mailmap, size_t idx);
+GIT_EXTERN(int) git_mailmap_from_repository(
+	git_mailmap **out, git_repository *repo);
 
 /**
- * Lookup a mailmap entry by name/email pair.
+ * Resolve a name and email to the corresponding real name and email.
  *
- * Do not free the mailmap entry, it is owned by the mailmap.
+ * The lifetime of the strings are tied to `mm`, `name`, and `email` parameters.
  *
- * @param mailmap the mailmap to perform the lookup in. (may be NULL)
- * @param name the name to perform the lookup with.
- * @param email the email to perform the lookup with.
- * @return the corresponding mailmap entry, or NULL if it cannot be found.
+ * @param real_name pointer to store the real name
+ * @param real_email pointer to store the real email
+ * @param mm the mailmap to perform a lookup with (may be NULL)
+ * @param name the name to look up
+ * @param email the email to look up
+ * @return 0 on success, or an error code
  */
-GIT_EXTERN(const git_mailmap_entry *) git_mailmap_entry_lookup(
-	const git_mailmap *mailmap, const char *name, const char *email);
+GIT_EXTERN(int) git_mailmap_resolve(
+	const char **real_name, const char **real_email,
+	const git_mailmap *mm, const char *name, const char *email);
 
 /** @} */
 GIT_END_DECL
diff --git a/src/blame.c b/src/blame.c
index 0624bf4..fc87bd1 100644
--- a/src/blame.c
+++ b/src/blame.c
@@ -134,7 +134,7 @@ git_blame* git_blame__alloc(
 	}
 
 	if (opts.flags & GIT_BLAME_USE_MAILMAP)
-		git_mailmap_from_repo(&gbr->mailmap, repo);
+		git_mailmap_from_repository(&gbr->mailmap, repo);
 
 	return gbr;
 }
diff --git a/src/mailmap.c b/src/mailmap.c
index a178c31..3da46a8 100644
--- a/src/mailmap.c
+++ b/src/mailmap.c
@@ -5,21 +5,20 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "git2/mailmap.h"
+#include "mailmap.h"
 
+#include "common.h"
+#include "path.h"
+#include "repository.h"
+#include "git2/config.h"
+#include "git2/revparse.h"
 #include "blob.h"
-#include "commit.h"
 #include "parse.h"
-#include "git2/common.h"
-#include "git2/repository.h"
-#include "git2/revparse.h"
-#include "git2/sys/commit.h"
-
-#define MAILMAP_FILE ".mailmap"
 
-struct git_mailmap {
-	git_vector entries;
-};
+#define MM_FILE ".mailmap"
+#define MM_FILE_CONFIG "mailmap.file"
+#define MM_BLOB_CONFIG "mailmap.blob"
+#define MM_BLOB_DEFAULT "HEAD:" MM_FILE
 
 static void mailmap_entry_free(git_mailmap_entry *entry)
 {
@@ -33,6 +32,37 @@ static void mailmap_entry_free(git_mailmap_entry *entry)
 	git__free(entry);
 }
 
+/*
+ * First we sort by replace_email, then replace_name (if present).
+ * Entries with names are greater than entries without.
+ */
+static int mailmap_entry_cmp(const void *a_raw, const void *b_raw)
+{
+	const git_mailmap_entry *a = (const git_mailmap_entry *)a_raw;
+	const git_mailmap_entry *b = (const git_mailmap_entry *)b_raw;
+	int cmp;
+
+	assert(a && b && a->replace_email && b->replace_email);
+
+	cmp = git__strcmp(a->replace_email, b->replace_email);
+	if (cmp)
+		return cmp;
+
+	/* NULL replace_names are less than not-NULL ones */
+	if (a->replace_name == NULL || b->replace_name == NULL)
+		return (int)(a->replace_name != NULL) - (int)(b->replace_name != NULL);
+
+	return git__strcmp(a->replace_name, b->replace_name);
+}
+
+/* Replace the old entry with the new on duplicate. */
+static int mailmap_entry_replace(void **old_raw, void *new_raw)
+{
+	mailmap_entry_free((git_mailmap_entry *)*old_raw);
+	*old_raw = new_raw;
+	return GIT_EEXISTS;
+}
+
 /* Check if we're at the end of line, w/ comments */
 static bool is_eol(git_parse_ctx *ctx)
 {
@@ -114,12 +144,68 @@ static int parse_mailmap_entry(
 	return 0;
 }
 
-int git_mailmap_from_buffer(git_mailmap **out, git_buf *buf)
+int git_mailmap_new(git_mailmap **out)
+{
+	int error;
+	git_mailmap *mm = git__calloc(1, sizeof(git_mailmap));
+	GITERR_CHECK_ALLOC(mm);
+
+	error = git_vector_init(&mm->entries, 0, mailmap_entry_cmp);
+	if (error < 0) {
+		git__free(mm);
+		return error;
+	}
+	*out = mm;
+	return 0;
+}
+
+void git_mailmap_free(git_mailmap *mm)
+{
+	size_t idx;
+	git_mailmap_entry *entry;
+	if (!mm)
+		return;
+
+	git_vector_foreach(&mm->entries, idx, entry)
+		mailmap_entry_free(entry);
+	git__free(mm);
+}
+
+int git_mailmap_add_entry(
+	git_mailmap *mm, const char *real_name, const char *real_email,
+	const char *replace_name, const char *replace_email)
+{
+	int error;
+	git_mailmap_entry *entry = git__calloc(1, sizeof(git_mailmap_entry));
+	GITERR_CHECK_ALLOC(entry);
+
+	assert(mm && replace_email && *replace_email);
+
+	if (real_name && *real_name) {
+		entry->real_name = git__strdup(real_name);
+		GITERR_CHECK_ALLOC(entry->real_name);
+	}
+	if (real_email && *real_email) {
+		entry->real_email = git__strdup(real_email);
+		GITERR_CHECK_ALLOC(entry->real_email);
+	}
+	if (replace_name && *replace_name) {
+		entry->replace_name = git__strdup(replace_name);
+		GITERR_CHECK_ALLOC(entry->replace_name);
+	}
+	entry->replace_email = git__strdup(replace_email);
+	GITERR_CHECK_ALLOC(entry->replace_email);
+
+	error = git_vector_insert_sorted(&mm->entries, entry, mailmap_entry_replace);
+	if (error < 0 && error != GIT_EEXISTS)
+		mailmap_entry_free(entry);
+
+	return error;
+}
+
+int git_mailmap_add_buffer(git_mailmap *mm, const git_buf *buf)
 {
 	int error;
-	git_mailmap *mm;
-	size_t entry_size;
-	char *entry_data;
 	git_mailmap_entry *entry = NULL;
 	git_parse_ctx ctx;
 
@@ -134,14 +220,6 @@ int git_mailmap_from_buffer(git_mailmap **out, git_buf *buf)
 
 	git_parse_ctx_init(&ctx, buf->ptr, buf->size);
 
-	/* Create our mailmap object */
-	mm = git__calloc(1, sizeof(git_mailmap));
-	GITERR_CHECK_ALLOC(mm);
-
-	error = git_vector_init(&mm->entries, 0, NULL);
-	if (error < 0)
-		goto cleanup;
-
 	/* Run the parser */
 	while (ctx.remain_len > 0) {
 		error = parse_mailmap_entry(
@@ -154,7 +232,6 @@ int git_mailmap_from_buffer(git_mailmap **out, git_buf *buf)
 
 		entry = git__calloc(1, sizeof(git_mailmap_entry));
 		GITERR_CHECK_ALLOC(entry);
-		entry->version = GIT_MAILMAP_ENTRY_VERSION;
 
 		if (real_name.size > 0) {
 			entry->real_name = git__substrdup(real_name.ptr, real_name.size);
@@ -171,19 +248,17 @@ int git_mailmap_from_buffer(git_mailmap **out, git_buf *buf)
 		entry->replace_email = git__substrdup(replace_email.ptr, replace_email.size);
 		GITERR_CHECK_ALLOC(entry->replace_email);
 
-		error = git_vector_insert(&mm->entries, entry);
-		if (error < 0)
+		error = git_vector_insert_sorted(
+			&mm->entries, entry, mailmap_entry_replace);
+		if (error < 0 && error != GIT_EEXISTS)
 			goto cleanup;
+
 		entry = NULL;
+		error = 0;
 	}
 
-	/* fill in *out, and make sure we don't free our mailmap */
-	*out = mm;
-	mm = NULL;
-
 cleanup:
 	mailmap_entry_free(entry);
-	git_mailmap_free(mm);
 
 	/* We never allocate data in these buffers, but better safe than sorry */
 	git_buf_free(&real_name);
@@ -193,157 +268,192 @@ cleanup:
 	return error;
 }
 
-void git_mailmap_free(git_mailmap *mailmap)
-{
-	if (!mailmap)
-		return;
-
-	git_vector_foreach(&mailmap->entries, i, entry) {
-		mailmap_entry_free(entry);
-	}
-	git_vector_free(&mailmap->entries);
-
-	git__free(mailmap);
-}
-
-int git_mailmap_resolve(
-	const char **name_out, const char **email_out,
-	const git_mailmap *mailmap,
-	const char *name, const char *email)
-{
-	const git_mailmap_entry *entry = NULL;
-	assert(name && email);
-
-	*name_out = name;
-	*email_out = email;
-
-	if (!mailmap)
-		return 0;
-
-	entry = git_mailmap_entry_lookup(mailmap, name, email);
-	if (entry) {
-		if (entry->real_name)
-			*name_out = entry->real_name;
-		if (entry->real_email)
-			*email_out = entry->real_email;
-	}
-	return 0;
-}
-
-const git_mailmap_entry *git_mailmap_entry_lookup(
-	const git_mailmap *mailmap, const char *name, const char *email)
+int git_mailmap_from_buffer(git_mailmap **out, const git_buf *buffer)
 {
-	size_t i;
-	git_mailmap_entry *entry;
-	assert(name && email);
-
-	if (!mailmap)
-		return NULL;
-
-	git_vector_foreach(&mailmap->entries, i, entry) {
-		if (git__strcmp(email, entry->replace_email))
-			continue;
-		if (entry->replace_name && git__strcmp(name, entry->replace_name))
-			continue;
+	int error = git_mailmap_new(out);
+	if (error < 0)
+		return error;
 
-		return entry;
+	error = git_mailmap_add_buffer(*out, buffer);
+	if (error < 0) {
+		git_mailmap_free(*out);
+		*out = NULL;
 	}
-
-	return NULL;
-}
-
-const git_mailmap_entry *git_mailmap_entry_byindex(
-	const git_mailmap *mailmap, size_t idx)
-{
-	if (mailmap)
-		return git_vector_get(&mailmap->entries, idx);
-	return NULL;
-}
-
-size_t git_mailmap_entry_count(const git_mailmap *mailmap)
-{
-	if (mailmap)
-		return git_vector_length(&mailmap->entries);
-	return 0;
+	return error;
 }
 
-static int mailmap_from_bare_repo(git_mailmap **mailmap, git_repository *repo)
+static int mailmap_add_blob(
+	git_mailmap *mm, git_repository *repo, const char *spec)
 {
-	git_reference *head = NULL;
-	git_object *tree = NULL;
+	git_object *object = NULL;
 	git_blob *blob = NULL;
 	git_buf content = GIT_BUF_INIT;
 	int error;
 
-	assert(git_repository_is_bare(repo));
+	assert(mm && repo);
 
-	/* In bare repositories, fall back to reading from HEAD's tree */
-	error = git_repository_head(&head, repo);
+	error = git_revparse_single(&object, repo, spec);
 	if (error < 0)
 		goto cleanup;
 
-	error = git_reference_peel(&tree, head, GIT_OBJ_TREE);
+	error = git_object_peel((git_object **)&blob, object, GIT_OBJ_BLOB);
 	if (error < 0)
 		goto cleanup;
 
-	error = git_object_lookup_bypath(
-		(git_object **) &blob, tree, MAILMAP_FILE, GIT_OBJ_BLOB);
+	error = git_blob__getbuf(&content, blob);
 	if (error < 0)
 		goto cleanup;
 
-	error = git_blob_filtered_content(&content, blob, MAILMAP_FILE, false);
-	if (error < 0)
-		goto cleanup;
-
-	error = git_mailmap_from_buffer(mailmap, &content);
+	error = git_mailmap_add_buffer(mm, &content);
 	if (error < 0)
 		goto cleanup;
 
 cleanup:
 	git_buf_free(&content);
 	git_blob_free(blob);
-	git_object_free(tree);
-	git_reference_free(head);
-
+	git_object_free(object);
 	return error;
 }
 
-static int mailmap_from_workdir_repo(git_mailmap **mailmap, git_repository *repo)
+static int mailmap_add_file_ondisk(
+	git_mailmap *mm, const char *path, git_repository *repo)
 {
-	git_buf path = GIT_BUF_INIT;
-	git_buf data = GIT_BUF_INIT;
+	const char *base = repo ? git_repository_workdir(repo) : NULL;
+	git_buf fullpath = GIT_BUF_INIT;
+	git_buf content = GIT_BUF_INIT;
 	int error;
 
-	assert(!git_repository_is_bare(repo));
-
-	/* In non-bare repositories, .mailmap should be read from the workdir */
-	error = git_buf_joinpath(&path, git_repository_workdir(repo), MAILMAP_FILE);
+	error = git_path_join_unrooted(&fullpath, path, base, NULL);
 	if (error < 0)
 		goto cleanup;
 
-	error = git_futils_readbuffer(&data, git_buf_cstr(&path));
+	error = git_futils_readbuffer(&content, fullpath.ptr);
 	if (error < 0)
 		goto cleanup;
 
-	error = git_mailmap_from_buffer(mailmap, &data);
+	error = git_mailmap_add_buffer(mm, &content);
 	if (error < 0)
 		goto cleanup;
 
 cleanup:
-	git_buf_free(&path);
-	git_buf_free(&data);
-
+	git_buf_free(&fullpath);
+	git_buf_free(&content);
 	return error;
 }
 
-int git_mailmap_from_repo(git_mailmap **mailmap, git_repository *repo)
+/* NOTE: Only expose with an error return, currently never errors */
+static void mailmap_add_from_repository(git_mailmap *mm, git_repository *repo)
 {
-	assert(mailmap && repo);
+	git_config *config = NULL;
+	git_buf spec_buf = GIT_BUF_INIT;
+	git_buf path_buf = GIT_BUF_INIT;
+	const char *spec = NULL;
+	const char *path = NULL;
+
+	assert(mm && repo);
+
+	/* If we're in a bare repo, default blob to 'HEAD:.mailmap' */
+	if (repo->is_bare)
+		spec = MM_BLOB_DEFAULT;
+
+	/* Try to load 'mailmap.file' and 'mailmap.blob' cfgs from the repo */
+	if (git_repository_config(&config, repo) == 0) {
+		if (git_config_get_string_buf(&spec_buf, config, MM_BLOB_CONFIG) == 0)
+			spec = spec_buf.ptr;
+		if (git_config_get_path(&path_buf, config, MM_FILE_CONFIG) == 0)
+			path = path_buf.ptr;
+	}
 
-	*mailmap = NULL;
+	/*
+	 * Load mailmap files in order, overriding previous entries with new ones.
+	 *  1. The '.mailmap' file in the repository's workdir root,
+	 *  2. The blob described by the 'mailmap.blob' config (default HEAD:.mailmap),
+	 *  3. The file described by the 'mailmap.file' config.
+	 *
+	 * We ignore errors from these loads, as these files may not exist, or may
+	 * contain invalid information, and we don't want to report that error.
+	 *
+	 * XXX: Warn?
+	 */
+	if (!repo->is_bare)
+		mailmap_add_file_ondisk(mm, MM_FILE, repo);
+	if (spec != NULL)
+		mailmap_add_blob(mm, repo, spec);
+	if (path != NULL)
+		mailmap_add_file_ondisk(mm, path, repo);
+
+	git_buf_free(&spec_buf);
+	git_buf_free(&path_buf);
+	git_config_free(config);
+}
 
-	if (git_repository_is_bare(repo))
-		return mailmap_from_bare_repo(mailmap, repo);
-	else
-		return mailmap_from_workdir_repo(mailmap, repo);
+int git_mailmap_from_repository(git_mailmap **out, git_repository *repo)
+{
+	int error = git_mailmap_new(out);
+	if (error < 0)
+		return error;
+	mailmap_add_from_repository(*out, repo);
+	return 0;
+}
+
+const git_mailmap_entry *git_mailmap_entry_lookup(
+	const git_mailmap *mm, const char *name, const char *email)
+{
+	int error;
+	ssize_t fallback = -1;
+	size_t idx;
+	git_mailmap_entry *entry;
+	git_mailmap_entry needle = { NULL, NULL, NULL, (char *)email };
+
+	assert(email);
+
+	if (!mm)
+		return NULL;
+
+	/*
+	 * We want to find the place to start looking. so we do a binary search for
+	 * the "fallback" nameless entry. If we find it, we advance past it and record
+	 * the index.
+	 */
+	error = git_vector_bsearch(&idx, (git_vector *)&mm->entries, &needle);
+	if (error >= 0)
+		fallback = idx++;
+	else if (error != GIT_ENOTFOUND)
+		return NULL;
+
+	/* do a linear search for an exact match */
+	for (; idx < git_vector_length(&mm->entries); ++idx) {
+		entry = git_vector_get(&mm->entries, idx);
+
+		if (git__strcmp(entry->replace_email, email))
+			break; /* it's a different email, so we're done looking */
+
+		assert(entry->replace_name); /* should be specific */
+		if (!name || !git__strcmp(entry->replace_name, name))
+			return entry;
+	}
+
+	if (fallback < 0)
+		return NULL; /* no fallback */
+	return git_vector_get(&mm->entries, fallback);
+}
+
+int git_mailmap_resolve(
+	const char **real_name, const char **real_email,
+	const git_mailmap *mailmap,
+	const char *name, const char *email)
+{
+	const git_mailmap_entry *entry = NULL;
+	assert(name && email);
+
+	*real_name = name;
+	*real_email = email;
+
+	if ((entry = git_mailmap_entry_lookup(mailmap, name, email))) {
+		if (entry->real_name)
+			*real_name = entry->real_name;
+		if (entry->real_email)
+			*real_email = entry->real_email;
+	}
+	return 0;
 }
diff --git a/src/mailmap.h b/src/mailmap.h
new file mode 100644
index 0000000..2c9736a
--- /dev/null
+++ b/src/mailmap.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_mailmap_h__
+#define INCLUDE_mailmap_h__
+
+#include "git2/mailmap.h"
+#include "vector.h"
+
+/*
+ * A mailmap is stored as a sorted vector of 'git_mailmap_entry's. These entries
+ * are sorted first by 'replace_email', and then by 'replace_name'. NULL
+ * replace_names are ordered first.
+ *
+ * Looking up a name and email in the mailmap is done with a binary search.
+ */
+struct git_mailmap {
+	git_vector entries;
+};
+
+/* Single entry parsed from a mailmap */
+typedef struct git_mailmap_entry {
+	char *real_name; /**< the real name (may be NULL) */
+	char *real_email; /**< the real email (may be NULL) */
+	char *replace_name; /**< the name to replace (may be NULL) */
+	char *replace_email; /**< the email to replace */
+} git_mailmap_entry;
+
+const git_mailmap_entry *git_mailmap_entry_lookup(
+	const git_mailmap *mm, const char *name, const char *email);
+
+#endif
diff --git a/src/signature.c b/src/signature.c
index d922fda..a8177e0 100644
--- a/src/signature.c
+++ b/src/signature.c
@@ -116,7 +116,8 @@ int git_signature_with_mailmap(
 	if (source == NULL)
 		return 0;
 
-	error = git_mailmap_resolve(&name, &email, mailmap, source->name, source->email);
+	error = git_mailmap_resolve(
+		&name, &email, mailmap, source->name, source->email);
 	if (error < 0)
 		return error;