[PATCH 1/4] Introduce commit notes

@@ -431,6 +431,21 @@ core.inithook::
 	linkgit:git-init[1].  The hook is called with the argument
 	"reinit" if an existing repository is re-initialized.
 
+core.notesRef::
+	When showing commit messages, also show notes which are stored in
+	the given ref.  This ref is expected to contain paths of the form
+	??/*, where the directory name consists of the first two
+	characters of the commit name, and the base name consists of
+	the remaining 38 characters.
++
+If such a path exists in the given ref, the referenced blob is read, and
+appended to the commit message, separated by a "Notes:" line.  If the
+given ref itself does not exist, it is not an error, but means that no
+notes should be print.
++
+This setting defaults to "refs/notes/commits", and can be overridden by
+the `GIT_NOTES_REF` environment variable.
+
 alias.*::
 	Command aliases for the linkgit:git[1] command wrapper - e.g.
 	after defining "alias.last = cat-file commit HEAD", the invocation

@@ -371,6 +371,7 @@ LIB_H += ll-merge.h
 LIB_H += log-tree.h
 LIB_H += mailmap.h
 LIB_H += merge-recursive.h
+LIB_H += notes.h
 LIB_H += object.h
 LIB_H += pack.h
 LIB_H += pack-refs.h

@@ -454,6 +455,7 @@ LIB_OBJS += match-trees.o
 LIB_OBJS += merge-file.o
 LIB_OBJS += merge-recursive.o
 LIB_OBJS += name-hash.o
+LIB_OBJS += notes.o
 LIB_OBJS += object.o
 LIB_OBJS += pack-check.o
 LIB_OBJS += pack-refs.o

@@ -375,6 +375,8 @@ static inline enum object_type object_type(unsigned int mode)
 #define GITATTRIBUTES_FILE ".gitattributes"
 #define INFOATTRIBUTES_FILE "info/attributes"
 #define ATTRIBUTE_MACRO_PREFIX "[attr]"
+#define GIT_NOTES_REF_ENVIRONMENT "GIT_NOTES_REF"
+#define GIT_NOTES_DEFAULT_REF "refs/notes/commits"
 
 extern int is_bare_repository_cfg;
 extern int is_bare_repository(void);

@@ -548,6 +550,7 @@ enum rebase_setup_type {
 extern enum branch_track git_branch_track;
 extern enum rebase_setup_type autorebase;
 extern int keep_hard_links;
+extern char *notes_ref_name;
 
 #define GIT_REPO_VERSION 0
 extern int repository_format_version;

@@ -5,6 +5,7 @@
 #include "utf8.h"
 #include "diff.h"
 #include "revision.h"
+#include "notes.h"
 
 int save_commit_buffer = 1;
 

@@ -469,6 +469,11 @@ static int git_default_core_config(const char *var, const char *value)
 		return 0;
 	}
 
+	if (!strcmp(var, "core.notesref")) {
+		notes_ref_name = xstrdup(value);
+		return 0;
+	}
+
 	if (!strcmp(var, "core.pager"))
 		return git_config_string(&pager_program, var, value);
 

@@ -46,6 +46,7 @@ int keep_hard_links = 0;
 
 /* Parallel index stat data preload? */
 int core_preload_index = 0;
+char *notes_ref_name;
 
 /* This is set by setup_git_dir_gently() and/or git_default_config() */
 char *git_work_tree_cfg;

@@ -0,0 +1,68 @@
+#include "cache.h"
+#include "commit.h"
+#include "notes.h"
+#include "refs.h"
+#include "utf8.h"
+#include "strbuf.h"
+
+static int initialized;
+
+void get_commit_notes(const struct commit *commit, struct strbuf *sb,
+		const char *output_encoding)
+{
+	static const char *utf8 = "utf-8";
+	struct strbuf name = STRBUF_INIT;
+	const char *hex;
+	unsigned char sha1[20];
+	char *msg;
+	unsigned long msgoffset, msglen;
+	enum object_type type;
+
+	if (!initialized) {
+		const char *env = getenv(GIT_NOTES_REF_ENVIRONMENT);
+		if (env)
+			notes_ref_name = getenv(GIT_NOTES_REF_ENVIRONMENT);
+		else if (!notes_ref_name)
+			notes_ref_name = GIT_NOTES_DEFAULT_REF;
+		if (notes_ref_name && read_ref(notes_ref_name, sha1))
+			notes_ref_name = NULL;
+		initialized = 1;
+	}
+
+	if (!notes_ref_name)
+		return;
+
+	strbuf_addf(&name, "%s:%s", notes_ref_name,
+			sha1_to_hex(commit->object.sha1));
+	if (get_sha1(name.buf, sha1))
+		return;
+
+	if (!(msg = read_sha1_file(sha1, &type, &msglen)) || !msglen ||
+			type != OBJ_BLOB)
+		return;
+
+	if (output_encoding && *output_encoding &&
+			strcmp(utf8, output_encoding)) {
+		char *reencoded = reencode_string(msg, output_encoding, utf8);
+		if (reencoded) {
+			free(msg);
+			msg = reencoded;
+			msglen = strlen(msg);
+		}
+	}
+
+	/* we will end the annotation by a newline anyway */
+	if (msglen && msg[msglen - 1] == '\n')
+		msglen--;
+
+	strbuf_addstr(sb, "\nNotes:\n");
+
+	for (msgoffset = 0; msgoffset < msglen;) {
+		int linelen = strchrnul(msg, '\n') - msg;
+
+		strbuf_addstr(sb, "    ");
+		strbuf_add(sb, msg + msgoffset, linelen);
+		msgoffset += linelen;
+	}
+	free(msg);
+}

@@ -0,0 +1,7 @@
+#ifndef NOTES_H
+#define NOTES_H
+
+void get_commit_notes(const struct commit *commit, struct strbuf *sb,
+		const char *output_encoding);
+
+#endif

@@ -6,6 +6,7 @@
 #include "string-list.h"
 #include "mailmap.h"
 #include "log-tree.h"
+#include "notes.h"
 
 static char *user_format;
 

@@ -911,5 +912,9 @@ void pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit,
 	 */
 	if (fmt == CMIT_FMT_EMAIL && sb->len <= beginning_of_body)
 		strbuf_addch(sb, '\n');
+
+	if (fmt != CMIT_FMT_ONELINE)
+		get_commit_notes(commit, sb, encoding);
+
 	free(reencoded);
 }