Add external API to access detailed commit attributes

The following new external methods have been added:

GIT_EXTERN(const char *) git_commit_message_short(git_commit *commit);
GIT_EXTERN(const char *) git_commit_message(git_commit *commit);
GIT_EXTERN(time_t) git_commit_time(git_commit *commit);
GIT_EXTERN(const git_commit_person *) git_commit_committer(git_commit *commit);
GIT_EXTERN(const git_commit_person *) git_commit_author(git_commit *commit);
GIT_EXTERN(const git_tree *) git_commit_tree(git_commit *commit);

A new structure, git_commit_person has been added to represent a
commit's author or committer.

The parsing of a commit has been split in two phases.
When adding a commit to the revision pool:
	- the commit's ODB object is opened
	- its raw contents are parsed for commit TIME, PARENTS and TREE
		(the minimal amount of data required to traverse the pool)
	- the commit's ODB object is closed

When querying for extended information on a commit:
	- the commit's ODB object is reopened
	- its raw contents are parsed for the requested information
	- the commit's ODB object remains open to handle additional queries

New unit tests have been added for the new functionality:

	In t0401-parse: parse_person_test
	In t0402-details: query_details_test

Signed-off-by: Vicent Marti <tanoku@gmail.com>

src/commit.c

@@ -29,14 +29,22 @@
 #include "git/odb.h"
 
 #define COMMIT_PRINT(commit) {\
-    char oid[41]; oid[40] = 0;\
-    git_oid_fmt(oid, &commit->object.id);\
-    printf("Oid: %s | In degree: %d | Time: %u\n", oid, commit->in_degree, commit->commit_time);\
+	char oid[41]; oid[40] = 0;\
+	git_oid_fmt(oid, &commit->object.id);\
+	printf("Oid: %s | In degree: %d | Time: %u\n", oid, commit->in_degree, commit->commit_time);\
 }
 
 void git_commit__free(git_commit *commit)
 {
 	git_commit_list_clear(&commit->parents, 0);
+
+	if (commit->odb_open)
+		git_obj_close(&commit->odb_object);
+
+	free(commit->author);
+	free(commit->committer);
+	free(commit->message);
+	free(commit->message_short);
 	free(commit);
 }
 
@@ -69,7 +77,7 @@ git_commit *git_commit_parse(git_revpool *pool, const git_oid *id)
 	if ((commit = git_commit_lookup(pool, id)) == NULL)
 		return NULL;
 
-	if (git_commit_parse_existing(commit) < 0)
+	if (git_commit__parse_basic(commit) < 0)
 		goto error_cleanup;
 
 	return commit;
@@ -79,30 +87,51 @@ error_cleanup:
 	return NULL;
 }
 
-int git_commit_parse_existing(git_commit *commit)
+int git_commit__parse(git_commit *commit, unsigned int parse_flags, int close_db_object)
 {
 	int error = 0;
-	git_obj commit_obj;
 
-	if (commit->parsed)
-		return 0;
+	if (!commit->odb_open) {
+		error = git_odb_read(&commit->odb_object, commit->object.pool->db, &commit->object.id);
+		if (error < 0)
+			return error;
 
-	error = git_odb_read(&commit_obj, commit->object.pool->db, &commit->object.id);
-	if (error < 0)
-		return error;
+		if (commit->odb_object.type != GIT_OBJ_COMMIT) {
+			git_obj_close(&commit->odb_object);
+			return GIT_EOBJTYPE;
+		}
 
-	if (commit_obj.type != GIT_OBJ_COMMIT) {
-		error = GIT_EOBJTYPE;
-		goto cleanup;
+		commit->odb_open = 1;
 	}
 
-	error = git_commit__parse_buffer(commit, commit_obj.data, commit_obj.len);
+	error = git_commit__parse_buffer(commit,
+			commit->odb_object.data, commit->odb_object.len, parse_flags);
+
+	if (close_db_object) {
+		git_obj_close(&commit->odb_object);
+		commit->odb_open = 0;
+	}
 
-cleanup:
-	git_obj_close(&commit_obj);
 	return error;
 }
 
+int git_commit__parse_basic(git_commit *commit)
+{
+	int error;
+
+	if (commit->basic_parse)
+		return 0;
+
+	error = git_commit__parse(commit,
+			(GIT_COMMIT_TREE | GIT_COMMIT_PARENTS | GIT_COMMIT_TIME), 1);
+
+	if (error < 0)
+		return error;
+
+	commit->basic_parse = 1;
+	return 0;
+}
+
 git_commit *git_commit_lookup(git_revpool *pool, const git_oid *id)
 {
 	git_commit *commit = NULL;
@@ -131,35 +160,67 @@ git_commit *git_commit_lookup(git_revpool *pool, const git_oid *id)
 	return commit;
 }
 
-int git_commit__parse_time(time_t *commit_time, char *buffer, const char *buffer_end)
+int git_commit__parse_person(git_commit_person *person, char **buffer_out,
+		const char *buffer_end, const char *header)
 {
-	if (memcmp(buffer, "author ", 7) != 0)
+	const size_t header_len = strlen(header);
+
+	int i;
+	char *buffer = *buffer_out;
+	char *line_end, *name, *email;
+
+	line_end = memchr(buffer, '\n', buffer_end - buffer);
+	if (!line_end)
 		return GIT_EOBJCORRUPTED;
 
-	buffer = memchr(buffer, '\n', buffer_end - buffer);
-	if (!buffer || ++buffer >= buffer_end)
+	if (buffer + (header_len + 1) > line_end)
 		return GIT_EOBJCORRUPTED;
 
-	if (memcmp(buffer, "committer ", 10) != 0)
+	if (memcmp(buffer, header, header_len) != 0)
 		return GIT_EOBJCORRUPTED;
 
-	buffer = memchr(buffer, '>', buffer_end - buffer);
-	if (!buffer || ++buffer >= buffer_end)
+	buffer += header_len;
+
+
+	/* Parse name field */
+	for (i = 0, name = person->name;
+		 i < 64 && buffer < line_end && *buffer != '<';
+		 ++i)
+		*name++ = *buffer++;
+
+	*(name - 1) = 0;
+
+	while (buffer < line_end && *buffer != '<')
+		buffer++;
+
+	if (++buffer >= line_end)
 		return GIT_EOBJCORRUPTED;
 
-	*commit_time = strtol(buffer, &buffer, 10);
+	/* Parse email field */
+	for (i = 0, email = person->email;
+		 i < 64 && buffer < line_end && *buffer != '>';
+		 ++i)
+		*email++ = *buffer++;
+
+	*email = 0;
+
+	while (buffer < line_end && *buffer != '>')
+		buffer++;
 
-	if (*commit_time == 0)
+	if (++buffer >= line_end)
 		return GIT_EOBJCORRUPTED;
 
-	buffer = memchr(buffer, '\n', buffer_end - buffer);
-	if (!buffer || ++buffer >= buffer_end)
+	person->time = strtol(buffer, &buffer, 10);
+
+	if (person->time == 0)
 		return GIT_EOBJCORRUPTED;
 
-	return (buffer < buffer_end) ? 0 : -1;
+	*buffer_out = (line_end + 1);
+	return 0;
 }
 
-int git_commit__parse_oid(git_oid *oid, char **buffer_out, const char *buffer_end, const char *header)
+int git_commit__parse_oid(git_oid *oid, char **buffer_out,
+		const char *buffer_end, const char *header)
 {
 	const size_t sha_len = GIT_OID_HEXSZ;
 	const size_t header_len = strlen(header);
@@ -183,28 +244,33 @@ int git_commit__parse_oid(git_oid *oid, char **buffer_out, const char *buffer_en
 	return 0;
 }
 
-int git_commit__parse_buffer(git_commit *commit, void *data, size_t len)
+int git_commit__parse_buffer(git_commit *commit, void *data, size_t len, unsigned int parse_flags)
 {
 	char *buffer = (char *)data;
 	const char *buffer_end = (char *)data + len;
 
 	git_oid oid;
-
-	if (commit->parsed)
-		return 0;
+	git_commit_person person;
 
 	if (git_commit__parse_oid(&oid, &buffer, buffer_end, "tree ") < 0)
 		return GIT_EOBJCORRUPTED;
 
-	commit->tree = git_tree_lookup(commit->object.pool, &oid);
+	if (parse_flags & GIT_COMMIT_TREE)
+		commit->tree = git_tree_lookup(commit->object.pool, &oid);
 
 	/*
 	 * TODO: commit grafts!
 	 */
 
+	if (parse_flags & GIT_COMMIT_PARENTS)
+		git_commit_list_clear(&commit->parents, 0);
+
 	while (git_commit__parse_oid(&oid, &buffer, buffer_end, "parent ") == 0) {
 		git_commit *parent;
 
+		if ((parse_flags & GIT_COMMIT_PARENTS) == 0)
+			continue;
+
 		if ((parent = git_commit_lookup(commit->object.pool, &oid)) == NULL)
 			return GIT_ENOTFOUND;
 
@@ -216,14 +282,117 @@ int git_commit__parse_buffer(git_commit *commit, void *data, size_t len)
 			return GIT_ENOMEM;
 	}
 
-	if (git_commit__parse_time(&commit->commit_time, buffer, buffer_end) < 0)
+	if (git_commit__parse_person(&person, &buffer, buffer_end, "author ") < 0)
 		return GIT_EOBJCORRUPTED;
 
-	commit->parsed = 1;
+	if (parse_flags & GIT_COMMIT_AUTHOR) {
+		if (commit->author)
+			free(commit->author);
+
+		commit->author = git__malloc(sizeof(git_commit_person));
+		memcpy(commit->author, &person, sizeof(git_commit_person));
+	}
+
+	if (git_commit__parse_person(&person, &buffer, buffer_end, "committer ") < 0)
+		return GIT_EOBJCORRUPTED;
+
+	if (parse_flags & GIT_COMMIT_TIME)
+		commit->commit_time = person.time;
+
+	if (parse_flags & GIT_COMMIT_COMMITTER) {
+		if (commit->committer)
+			free(commit->committer);
+
+		commit->committer = git__malloc(sizeof(git_commit_person));
+		memcpy(commit->committer, &person, sizeof(git_commit_person));
+	}
+
+	/* parse commit message */
+	while (buffer <= buffer_end && *buffer == '\n')
+		buffer++;
+
+	if (buffer < buffer_end)
+	{
+		if (parse_flags & GIT_COMMIT_MESSAGE) {
+			size_t message_len = buffer_end - buffer;
+
+			commit->message = git__malloc(message_len + 1);
+			memcpy(commit->message, buffer, message_len);
+			commit->message[message_len] = 0;
+		}
+
+		if (parse_flags & GIT_COMMIT_MESSAGE_SHORT) {
+			char *line_end;
+			size_t message_len;
+
+			line_end = memchr(buffer, '\n', buffer_end - buffer);
+			message_len = line_end - buffer;
+
+			commit->message_short = git__malloc(message_len + 1);
+			memcpy(commit->message_short, buffer, message_len);
+			commit->message_short[message_len] = 0;
+		}
+	}
 
 	return 0;
 }
 
+const git_tree *git_commit_tree(git_commit *commit)
+{
+	if (commit->tree)
+		return commit->tree;
+
+	git_commit__parse(commit, GIT_COMMIT_TREE, 0);
+	return commit->tree;
+}
+
+const git_commit_person *git_commit_author(git_commit *commit)
+{
+	if (commit->author)
+		return commit->author;
+
+	git_commit__parse(commit, GIT_COMMIT_AUTHOR, 0);
+	return commit->author;
+}
+
+const git_commit_person *git_commit_committer(git_commit *commit)
+{
+	if (commit->committer)
+		return commit->committer;
+
+	git_commit__parse(commit, GIT_COMMIT_COMMITTER, 0);
+	return commit->committer;
+}
+
+time_t git_commit_time(git_commit *commit)
+{
+	if (commit->commit_time)
+		return commit->commit_time;
+
+	git_commit__parse(commit, GIT_COMMIT_TIME, 0);
+	return commit->commit_time;
+}
+
+const char *git_commit_message(git_commit *commit)
+{
+	if (commit->message)
+		return commit->message;
+
+	git_commit__parse(commit, GIT_COMMIT_MESSAGE, 0);
+	return commit->message;
+}
+
+const char *git_commit_message_short(git_commit *commit)
+{
+	if (commit->message_short)
+		return commit->message_short;
+
+	git_commit__parse(commit, GIT_COMMIT_MESSAGE_SHORT, 0);
+	return commit->message_short;
+}
+
+
+
 int git_commit_list_push_back(git_commit_list *list, git_commit *commit)
 {
 	git_commit_node *node = NULL;

src/commit.h

@@ -23,31 +23,46 @@ struct git_commit_list {
 typedef struct git_commit_list git_commit_list;
 typedef struct git_commit_node git_commit_node;
 
+#define GIT_COMMIT_TREE		(1 << 1)
+#define GIT_COMMIT_PARENTS	(1 << 2)
+#define GIT_COMMIT_AUTHOR	(1 << 3)
+#define GIT_COMMIT_COMMITTER (1 << 4)
+#define GIT_COMMIT_TIME		(1 << 5)
+#define GIT_COMMIT_MESSAGE	(1 << 6)
+#define GIT_COMMIT_MESSAGE_SHORT (1 << 7)
+#define GIT_COMMIT_FOOTERS	(1 << 8)
 
 struct git_commit {
 	git_revpool_object object;
+	git_obj odb_object;
 
 	time_t commit_time;
 	git_commit_list parents;
 
 	git_tree *tree;
+	git_commit_person *author;
+	git_commit_person *committer;
+
+	char *message;
+	char *message_short;
 
 	unsigned short in_degree;
-	unsigned parsed:1,
+	unsigned basic_parse:1,
+			 odb_open:1,
 			 seen:1,
 			 uninteresting:1,
 			 topo_delay:1,
-			 flags:26;
+			 flags:25;
 };
 
 void git_commit__free(git_commit *c);
+int git_commit__parse(git_commit *commit, unsigned int flags, int close_odb);
+int git_commit__parse_basic(git_commit *commit);
 int git_commit__parse_oid(git_oid *oid, char **buffer_out, const char *buffer_end, const char *header);
-int git_commit__parse_buffer(git_commit *commit, void *data, size_t len);
-int git_commit__parse_time(time_t *commit_time, char *buffer, const char *buffer_end);
+int git_commit__parse_buffer(git_commit *commit, void *data, size_t len, unsigned int parse_flags);
+int git_commit__parse_person(git_commit_person *person, char **buffer_out, const char *buffer_end, const char *header);
 void git_commit__mark_uninteresting(git_commit *commit);
 
-int git_commit_parse_existing(git_commit *commit);
-
 
 int git_commit_list_push_back(git_commit_list *list, git_commit *commit);
 int git_commit_list_push_front(git_commit_list *list, git_commit *commit);

src/git/commit.h

@@ -3,6 +3,7 @@
 
 #include "common.h"
 #include "oid.h"
+#include "tree.h"
 
 /**
  * @file git/commit.h
@@ -16,6 +17,13 @@ GIT_BEGIN_DECL
 /** Parsed representation of a commit object. */
 typedef struct git_commit git_commit;
 
+/** Parsed representation of an author/committer of a commit */
+typedef struct git_commit_person {
+	char name[64]; /**< Full name */
+	char email[64]; /**< Email address */
+	time_t time; /**< Time when this person commited the change */
+} git_commit_person;
+
 /**
  * Locate a reference to a commit without loading it.
  * The generated commit object is owned by the revision
@@ -45,11 +53,53 @@ GIT_EXTERN(git_commit *) git_commit_parse(git_revpool *pool, const git_oid *id);
 
 /**
  * Get the id of a commit.
- * @param commit a previously parsed commit.
+ * @param commit a previously loaded commit.
  * @return object identity for the commit.
  */
 GIT_EXTERN(const git_oid *) git_commit_id(git_commit *commit);
 
+/**
+ * Get the short (one line) message of a commit.
+ * @param commit a previously loaded commit.
+ * @return the short message of a commit
+ */
+GIT_EXTERN(const char *) git_commit_message_short(git_commit *commit);
+
+/**
+ * Get the full message of a commit.
+ * @param commit a previously loaded commit.
+ * @return the message of a commit
+ */
+GIT_EXTERN(const char *) git_commit_message(git_commit *commit);
+
+/**
+ * Get the commit time (i.e. committer time) of a commit.
+ * @param commit a previously loaded commit.
+ * @return the time of a commit
+ */
+GIT_EXTERN(time_t) git_commit_time(git_commit *commit);
+
+/**
+ * Get the committer of a commit.
+ * @param commit a previously loaded commit.
+ * @return the committer of a commit
+ */
+GIT_EXTERN(const git_commit_person *) git_commit_committer(git_commit *commit);
+
+/**
+ * Get the author of a commit.
+ * @param commit a previously loaded commit.
+ * @return the author of a commit
+ */
+GIT_EXTERN(const git_commit_person *) git_commit_author(git_commit *commit);
+
+/**
+ * Get the tree pointed to by a commit.
+ * @param commit a previously loaded commit.
+ * @return the tree of a commit
+ */
+GIT_EXTERN(const git_tree *) git_commit_tree(git_commit *commit);
+
 /** @} */
 GIT_END_DECL
 #endif

src/revwalk.c

@@ -92,8 +92,9 @@ int gitrp_push(git_revpool *pool, git_commit *commit)
 	if (commit->object.pool != pool || pool->walking)
 		return GIT_ERROR;
 
-	if (!commit->parsed) {
-		int error = git_commit_parse_existing(commit);
+	if (!commit->basic_parse) {
+		int error = git_commit__parse_basic(commit);
+
 		if (error < 0)
 			return error;
 	}
@@ -129,8 +130,8 @@ int gitrp__enroot(git_revpool *pool, git_commit *commit)
 	if (commit->seen)
 		return 0;
 
-	if (commit->parsed == 0) {
-		error = git_commit_parse_existing(commit);
+	if (!commit->basic_parse) {
+		error = git_commit__parse_basic(commit);
 		if (error < 0)
 			return error;
 	}

tests/t0402-details.c

+#include "test_lib.h"
+#include "test_helpers.h"
+#include "commit.h"
+
+#include <git/odb.h>
+#include <git/commit.h>
+#include <git/revwalk.h>
+
+static const char *odb_dir = "../t0501-objects";
+static const char *commit_ids[] = {
+    "a4a7dce85cf63874e984719f4fdd239f5145052f", /* 0 */
+    "9fd738e8f7967c078dceed8190330fc8648ee56a", /* 1 */
+    "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", /* 2 */
+    "c47800c7266a2be04c571c04d5a6614691ea99bd", /* 3 */
+    "8496071c1b46c854b31185ea97743be6a8774479", /* 4 */
+    "5b5b025afb0b4c913b4c338a42934a3863bf3644", /* 5 */
+};
+
+BEGIN_TEST(query_details_test)
+	const size_t commit_count = sizeof(commit_ids) / sizeof(const char *);
+
+	unsigned int i;
+    git_odb *db;
+    git_revpool *pool;
+
+    must_pass(git_odb_open(&db, odb_dir));
+
+    pool = gitrp_alloc(db);
+    must_be_true(pool != NULL);
+
+	for (i = 0; i < commit_count; ++i) {
+		git_oid id;
+		git_commit *commit;
+
+		const git_commit_person *author, *committer;
+		const char *message, *message_short;
+		time_t commit_time;
+
+		git_oid_mkstr(&id, commit_ids[i]);
+
+		commit = git_commit_parse(pool, &id);
+		must_be_true(commit != NULL);
+
+		message = git_commit_message(commit);
+		message_short = git_commit_message_short(commit);
+		author = git_commit_author(commit);
+		committer = git_commit_committer(commit);
+		commit_time = git_commit_time(commit);
+
+		must_be_true(strcmp(author->name, "Scott Chacon") == 0);
+		must_be_true(strcmp(author->email, "schacon@gmail.com") == 0);
+		must_be_true(strcmp(committer->name, "Scott Chacon") == 0);
+		must_be_true(strcmp(committer->email, "schacon@gmail.com") == 0);
+		must_be_true(strchr(message, '\n') != NULL);
+		must_be_true(strchr(message_short, '\n') == NULL);
+		must_be_true(commit_time > 0);
+	}
+
+    gitrp_free(pool);
+    git_odb_close(db);
+END_TEST