Add support for SHA-256 repositories

Use variable extensions.objectformat, if available, to determine the
length of the hash id in the current repository.

doc/manual.adoc

@@ -203,6 +203,8 @@ following variables.
 |%(repo:is-inside-work-tree)
 			|Whether Tig is running inside a work tree,
 			 either `true` or `false`.
+|%(repo:object-format)	|The hash algorithm used for the repository, e.g. `sha1`
+			 or `sha256`.
 |=============================================================================
 
 Example user-defined commands:

include/tig/main.h

@@ -19,7 +19,7 @@
 #include "tig/util.h"
 
 struct commit {
-	char id[SIZEOF_REV];		/* SHA1 ID. */
+	char id[SIZEOF_REV];		/* Hash ID. */
 	const struct ident *author;	/* Author of the commit. */
 	struct time time;		/* Date from the author ident. */
 	struct graph_canvas graph;	/* Ancestry chain graphics. */

include/tig/parse.h

@@ -31,17 +31,17 @@ bool parse_chunk_header(struct chunk_header *header, const char *line);
 bool parse_chunk_lineno(unsigned long *lineno, const char *chunk, int marker);
 
 struct blame_commit {
-	char id[SIZEOF_REV];		/* SHA1 ID. */
+	char id[SIZEOF_REV];		/* Hash ID. */
 	char title[128];		/* First line of the commit message. */
 	const struct ident *author;	/* Author of the commit. */
 	struct time time;		/* Date from the author ident. */
 	const char *filename;		/* Name of file. */
-	char parent_id[SIZEOF_REV];	/* Parent/previous SHA1 ID. */
+	char parent_id[SIZEOF_REV];	/* Parent/previous hash ID. */
 	const char *parent_filename;	/* Parent/previous name of file. */
 };
 
 struct blame_header {
-	char id[SIZEOF_REV];		/* SHA1 ID. */
+	char id[SIZEOF_REV];		/* Hash ID. */
 	size_t orig_lineno;
 	size_t lineno;
 	size_t group;

include/tig/refdb.h

@@ -17,19 +17,20 @@
 #include "tig/tig.h"
 #include "tig/types.h"
 #include "tig/util.h"
+#include "tig/repo.h"
 
 struct argv_env;
 
 struct ref {
 	struct ref *next;
 	enum reference_type type;
-	char id[SIZEOF_REV];	/* Commit SHA1 ID */
+	char id[SIZEOF_REV];	/* Commit hash ID */
 	unsigned int valid:1;	/* Is the ref still valid? */
 	char name[1];		/* Ref name; tag or head names are shortened. */
 };
 
 #define is_initial_commit()	(!get_ref_head())
-#define is_head_commit(rev)	(!strcmp((rev), "HEAD") || (get_ref_head() && !strncmp(rev, get_ref_head()->id, SIZEOF_REV - 1)))
+#define is_head_commit(rev)	(!strcmp((rev), "HEAD") || (get_ref_head() && !strncmp(rev, get_ref_head()->id, REPO_INFO_SIZEOF_REV - 1)))
 #define ref_is_tag(ref)		((ref)->type == REFERENCE_TAG || (ref)->type == REFERENCE_LOCAL_TAG)
 #define ref_is_remote(ref)	((ref)->type == REFERENCE_REMOTE || (ref)->type == REFERENCE_TRACKED_REMOTE)
 

include/tig/repo.h

@@ -16,11 +16,21 @@
 
 #include "tig/tig.h"
 
+typedef enum {
+	REPO_INFO_SHA1 = 40,
+	REPO_INFO_SHA256 = 64
+} repo_object_format;
+
+/* Holds a hash ID and an ending NUL. */
+#define REPO_INFO_SIZEOF_REV	(repo.object_format + 1)
+
 typedef char repo_ref[SIZEOF_REF];
 typedef char repo_rev[SIZEOF_REV];
 typedef char repo_str[SIZEOF_STR];
 
+/* Leave object_format in first position. */
 #define REPO_INFO(_) \
+	_(repo_object_format, object_format) \
 	_(repo_ref, head) \
 	_(repo_rev, head_id) \
 	_(repo_ref, remote) \

include/tig/string.h

@@ -85,7 +85,7 @@ void string_ncopy_do(char *dst, size_t dstlen, const char *src, size_t srclen);
 void string_copy_rev(char *dst, const char *src);
 void string_copy_rev_from_commit_line(char *dst, const char *src);
 
-#define string_rev_is_null(rev) !strncmp(rev, NULL_ID, STRING_SIZE(NULL_ID))
+#define string_rev_is_null(rev) !strncmp(rev, NULL_ID, REPO_INFO_SIZEOF_REV - 1)
 
 #define string_add(dst, from, src) \
 	string_ncopy_do(dst + (from), sizeof(dst) - (from), src, sizeof(src))

include/tig/tig.h

@@ -148,8 +148,8 @@
 
 #define SIZEOF_STR	1024	/* Default string size. */
 #define SIZEOF_MED_STR	8192	/* Medium string size. */
-#define SIZEOF_REF	256	/* Size of symbolic or SHA1 ID. */
-#define SIZEOF_REV	41	/* Holds a SHA-1 and an ending NUL. */
+#define SIZEOF_REF	256	/* Size of symbolic or hash ID. */
+#define SIZEOF_REV	65	/* Holds a SHA-1 or SHA-256 and an ending NUL. */
 
 /* This color name can be used to refer to the default term colors. */
 #define COLOR_DEFAULT	(-1)
@@ -164,7 +164,7 @@
 #define MIN_VIEW_WIDTH  4
 #define VSPLIT_SCALE	0.5
 
-#define NULL_ID		"0000000000000000000000000000000000000000"
+#define NULL_ID		"0000000000000000000000000000000000000000000000000000000000000000"
 
 #define S_ISGITLINK(mode) (((mode) & S_IFMT) == 0160000)
 

src/argv.c

@@ -415,6 +415,14 @@ bool_formatter(struct format_context *format, struct format_var *var)
 	return string_format_from(format->buf, &format->bufpos, "%s", value ? "true" : "false");
 }
 
+static bool
+repo_object_format_formatter(struct format_context *format, struct format_var *var)
+{
+	repo_object_format value = *(repo_object_format *)var->value_ref;
+
+	return string_format_from(format->buf, &format->bufpos, "%s", value == REPO_INFO_SHA256 ? "sha256" : "sha1");
+}
+
 static bool
 repo_str_formatter(struct format_context *format, struct format_var *var)
 {

src/blame.c

@@ -28,7 +28,7 @@
  */
 
 struct blame_history_state {
-	char id[SIZEOF_REV];		/* SHA1 ID. */
+	char id[SIZEOF_REV];		/* Hash ID. */
 	const char *filename;		/* Name of file. */
 };
 
@@ -187,15 +187,15 @@ get_blame_commit(struct view *view, const char *id)
 		if (!blame->commit)
 			continue;
 
-		if (!strncmp(blame->commit->id, id, SIZEOF_REV - 1))
+		if (!strncmp(blame->commit->id, id, REPO_INFO_SIZEOF_REV - 1))
 			return blame->commit;
 	}
 
 	{
 		struct blame_commit *commit = calloc(1, sizeof(*commit));
 
 		if (commit)
-			string_ncopy(commit->id, id, SIZEOF_REV);
+			string_ncopy(commit->id, id, REPO_INFO_SIZEOF_REV);
 		return commit;
 	}
 }

src/draw.c

@@ -15,6 +15,7 @@
 #include "tig/graph.h"
 #include "tig/draw.h"
 #include "tig/options.h"
+#include "tig/repo.h"
 #include "compat/hashtab.h"
 
 static const enum line_type palette_colors[] = {
@@ -267,7 +268,7 @@ draw_id(struct view *view, struct view_column *column, const char *id)
 		return false;
 
 	if (column->opt.id.color && id) {
-		hashval_t color = iterative_hash(id, SIZEOF_REV - 1, 0);
+		hashval_t color = iterative_hash(id, REPO_INFO_SIZEOF_REV - 1, 0);
 
 		type = palette_colors[color % ARRAY_SIZE(palette_colors)];
 	}

src/graph-v1.c

@@ -32,7 +32,7 @@ struct graph_symbol {
 
 struct graph_column {
 	struct graph_symbol symbol;
-	char id[SIZEOF_REV];		/* Parent SHA1 ID. */
+	char id[SIZEOF_REV];		/* Parent hash ID. */
 };
 
 struct graph_row {

src/graph-v2.c

@@ -48,7 +48,7 @@ struct graph_symbol {
 
 struct graph_column {
 	struct graph_symbol symbol;
-	const char *id;			/* Parent SHA1 ID. */
+	const char *id;			/* Parent hash ID. */
 };
 
 struct graph_row {

src/main.c

@@ -101,7 +101,7 @@ main_add_commit(struct view *view, enum line_type type, struct commit *template,
 	view_column_info_update(view, line);
 
 	if ((opt_start_on_head && is_head_commit(commit->id)) ||
-	    (view->env->goto_id[0] && !strncmp(view->env->goto_id, commit->id, SIZEOF_REV - 1)))
+	    (view->env->goto_id[0] && !strncmp(view->env->goto_id, commit->id, REPO_INFO_SIZEOF_REV - 1)))
 		select_view_line(view, line->lineno + 1);
 
 	return commit;
@@ -127,10 +127,11 @@ main_add_changes_commit(struct view *view, enum line_type type, const char *pare
 	if (!parent)
 		return true;
 
-	if (*parent)
-		string_copy_rev(ids + STRING_SIZE(NULL_ID " "), parent);
-	else
-		ids[STRING_SIZE(NULL_ID)] = 0;
+	if (*parent) {
+		ids[REPO_INFO_SIZEOF_REV - 1] = ' ';
+		string_copy_rev(ids + REPO_INFO_SIZEOF_REV, parent);
+	} else
+		ids[REPO_INFO_SIZEOF_REV - 1] = 0;
 
 	if (!time_now(&now, &tz)) {
 		commit.time.tz = tz.tz_minuteswest * 60;

src/options.c

@@ -701,9 +701,16 @@ parse_option(struct option_info *option, const char *prefix, const char *arg)
 		if (!strcmp(name, "line-number-interval") ||
 		    !strcmp(name, "tab-size"))
 			return parse_int(option->value, arg, 1, 1024);
-		else if (!strcmp(name, "id-width"))
-			return parse_int(option->value, arg, 0, SIZEOF_REV - 1);
-		else
+		else if (!strcmp(name, "id-width")) {
+			enum status_code code = parse_int(option->value, arg, 0, SIZEOF_REV - 1);
+			if (code == SUCCESS) {
+				int *value = option->value;
+				/* Limit id-width to the length of the hash used for the repository. */
+				if (*value > REPO_INFO_SIZEOF_REV - 1)
+					*value = REPO_INFO_SIZEOF_REV - 1;
+			}
+			return code;
+		} else
 			return parse_int(option->value, arg, 0, 1024);
 	}
 
@@ -1528,8 +1535,15 @@ read_repo_config_option(char *name, size_t namelen, char *value, size_t valuelen
 	else if (!strcmp(name, "core.worktree"))
 		string_ncopy(repo.worktree, value, valuelen);
 
-	else if (!strcmp(name, "core.abbrev"))
-		parse_int(&opt_id_width, value, 0, SIZEOF_REV - 1);
+	else if (!strcmp(name, "core.abbrev")) {
+		/* We cannot use REPO_INFO_SIZEOF_REV until we parse extensions.objectformat. */
+		if (!strcmp(value, "no"))
+			opt_id_width = SIZEOF_REV - 1;
+		else if (strcmp(value, "auto"))
+			parse_int(&opt_id_width, value, 0, SIZEOF_REV - 1);
+
+	} else if (!strcmp(name, "extensions.objectformat"))
+		repo.object_format = !strcmp(value, "sha256") ? REPO_INFO_SHA256 : REPO_INFO_SHA1;
 
 	else if (!strcmp(name, "diff.noprefix"))
 		parse_bool(&opt_diff_noprefix, value);
@@ -1578,6 +1592,10 @@ load_git_config(void)
 
 	code = io_run_load(&io, config_list_argv, "=", read_repo_config_option, NULL);
 
+	/* Limit id-width to the length of the hash used for the repository. */
+	if (opt_id_width > REPO_INFO_SIZEOF_REV - 1)
+		opt_id_width = REPO_INFO_SIZEOF_REV - 1;
+
 	if (git_worktree && *git_worktree)
 		string_ncopy(repo.worktree, git_worktree, strlen(git_worktree));
 

src/parse.c

@@ -14,6 +14,7 @@
 #include "tig/tig.h"
 #include "tig/parse.h"
 #include "tig/map.h"
+#include "tig/repo.h"
 
 size_t
 parse_size(const char *text)
@@ -109,12 +110,12 @@ parse_number(const char **posref, size_t *number)
 bool
 parse_blame_header(struct blame_header *header, const char *text)
 {
-	const char *pos = text + SIZEOF_REV - 2;
+	const char *pos = text + REPO_INFO_SIZEOF_REV - 2;
 
-	if (strlen(text) <= SIZEOF_REV || pos[1] != ' ')
+	if (strlen(text) <= REPO_INFO_SIZEOF_REV || pos[1] != ' ')
 		return false;
 
-	string_ncopy(header->id, text, SIZEOF_REV);
+	string_copy_rev(header->id, text);
 
 	if (!parse_number(&pos, &header->orig_lineno) ||
 	    !parse_number(&pos, &header->lineno))
@@ -163,10 +164,10 @@ parse_blame_info(struct blame_commit *commit, char author[SIZEOF_STR], char *lin
 		string_ncopy(commit->title, line, strlen(line));
 
 	} else if (match_blame_header("previous ", &line)) {
-		if (strlen(line) <= SIZEOF_REV)
+		if (strlen(line) <= REPO_INFO_SIZEOF_REV)
 			return false;
 		string_copy_rev(commit->parent_id, line);
-		line += SIZEOF_REV;
+		line += REPO_INFO_SIZEOF_REV;
 		commit->parent_filename = get_path(line);
 		if (!commit->parent_filename)
 			return true;

src/refdb.c

@@ -239,7 +239,7 @@ add_to_refs(const char *id, size_t idlen, char *name, size_t namelen, struct ref
 	}
 
 	/* If we are reloading or it's an annotated tag, replace the
-	 * previous SHA1 with the resolved commit id; relies on the fact
+	 * previous hash with the resolved commit id; relies on the fact
 	 * git-ls-remote lists the commit id of an annotated tag right
 	 * before the commit id it points to. */
 	if (type == REFERENCE_REPLACE) {
@@ -269,7 +269,7 @@ add_to_refs(const char *id, size_t idlen, char *name, size_t namelen, struct ref
 
 	ref->valid = true;
 	ref->type = type;
-	string_ncopy_do(ref->id, SIZEOF_REV, id, idlen);
+	string_ncopy_do(ref->id, REPO_INFO_SIZEOF_REV, id, idlen);
 
 	if (type == REFERENCE_HEAD) {
 		if (!refs_head ||

src/repo.c

@@ -57,7 +57,7 @@ read_repo_info(char *name, size_t namelen, char *value, size_t valuelen, void *d
 		 * this special case by looking at the emitted value. If it looks
 		 * like a commit ID and there's no cdup path assume that no value
 		 * was emitted. */
-		if (!*repo.cdup && namelen == 40 && iscommit(name))
+		if (!*repo.cdup && namelen == REPO_INFO_SIZEOF_REV - 1 && iscommit(name))
 			return read_repo_info(name, namelen, value, valuelen, data);
 
 		string_ncopy(repo.prefix, name, namelen);
@@ -102,6 +102,8 @@ load_repo_info(void)
 	};
 
 	memset(&repo, 0, sizeof(repo));
+	/* defaults to SHA-1 as older Git versions don't have extensions.objectFormat */
+	repo.object_format = REPO_INFO_SHA1;
 	return reload_repo_info(rev_parse_argv);
 }
 

src/status.c

@@ -111,7 +111,7 @@ status_run(struct view *view, const char *argv[], char status, enum line_type ty
 		if (status) {
 			file->status = status;
 			if (status == 'A')
-				string_copy(file->old.rev, NULL_ID);
+				string_copy_rev(file->old.rev, NULL_ID);
 
 		} else {
 			if (!status_get_diff(&parsed, buf.data, buf.size))

src/string.c

@@ -13,6 +13,7 @@
 
 #include "tig/tig.h"
 #include "tig/string.h"
+#include "tig/repo.h"
 #include "compat/utf8proc.h"
 
 /*
@@ -42,7 +43,7 @@ iscommit(const char *str)
 			return false;
 	}
 
-	return 7 <= pos && pos < SIZEOF_REV;
+	return 7 <= pos && pos < REPO_INFO_SIZEOF_REV;
 }
 
 int
@@ -72,11 +73,11 @@ string_copy_rev(char *dst, const char *src)
 	if (!*src)
 		return;
 
-	for (srclen = 0; srclen < SIZEOF_REV; srclen++)
+	for (srclen = 0; srclen < REPO_INFO_SIZEOF_REV; srclen++)
 		if (!src[srclen] || isspace((unsigned char)src[srclen]))
 			break;
 
-	string_ncopy_do(dst, SIZEOF_REV, src, srclen);
+	string_ncopy_do(dst, REPO_INFO_SIZEOF_REV, src, srclen);
 }
 
 void

src/tree.c

@@ -58,7 +58,7 @@ push_tree_stack_entry(struct view *view, const char *name, struct position *posi
  */
 
 #define SIZEOF_TREE_ATTR \
-	STRING_SIZE("100644 blob f931e1d229c3e185caad4449bf5b66ed72462657\t")
+	STRING_SIZE("100644 blob ") + REPO_INFO_SIZEOF_REV - 1 + STRING_SIZE("\t")
 
 #define SIZEOF_TREE_MODE \
 	STRING_SIZE("100644 ")