Merge advanced VFS-specific features

Most of these were done in private before microsoft/git. However,
the following pull requests modified the core feature:

	microsoft#85
	microsoft#89
	microsoft#91
	microsoft#98
	microsoft#243
	microsoft#263

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>

Author: dscho

BRANCHES.md

@@ -0,0 +1,59 @@
+Branches used in this repo
+==========================
+
+The document explains the branching structure that we are using in the VFSForGit repository as well as the forking strategy that we have adopted for contributing.
+
+Repo Branches
+-------------
+
+1. `vfs-#`
+
+    These branches are used to track the specific version that match Git for Windows with the VFSForGit specific patches on top.  When a new version of Git for Windows is released, the VFSForGit patches will be rebased on that windows version and a new gvfs-# branch created to create pull requests against.
+
+    #### Examples
+
+    ```
+    vfs-2.27.0
+    vfs-2.30.0
+    ```
+
+    The versions of git for VFSForGit are based on the Git for Windows versions.  v2.20.0.vfs.1 will correspond with the v2.20.0.windows.1 with the VFSForGit specific patches applied to the windows version.
+
+2. `vfs-#-exp`
+
+   These branches are for releasing experimental features to early adopters. They
+   should contain everything within the corresponding `vfs-#` branch; if the base
+   branch updates, then merge into the `vfs-#-exp` branch as well.
+
+Tags
+----
+
+We are using annotated tags to build the version number for git.  The build will look back through the commit history to find the first tag matching `v[0-9]*vfs*` and build the git version number using that tag.
+
+Full releases are of the form `v2.XX.Y.vfs.Z.W` where `v2.XX.Y` comes from the
+upstream version and `Z.W` are custom updates within our fork. Specifically,
+the `.Z` value represents the "compatibility level" with VFS for Git. Only
+increase this version when making a breaking change with a released version
+of VFS for Git. The `.W` version is used for minor updates between major
+versions.
+
+Experimental releases are of the form `v2.XX.Y.vfs.Z.W.exp`. The `.exp`
+suffix indicates that experimental features are available. The rest of the
+version string comes from the full release tag. These versions will only
+be made available as pre-releases on the releases page, never a full release.
+
+Forking
+-------
+
+A personal fork of this repository and a branch in that repository should be used for development.
+
+These branches should be based on the latest vfs-# branch.  If there are work in progress pull requests that you have based on a previous version branch when a new version branch is created, you will need to move your patches to the new branch to get them in that latest version.
+
+#### Example
+
+```
+git clone <personal fork repo URL>
+git remote add ms https://github.com/Microsoft/git.git
+git checkout -b my-changes ms/vfs-2.20.0 --no-track
+git push -fu origin HEAD
+```

Makefile

@@ -921,6 +921,7 @@ LIB_OBJS += gettext.o
 LIB_OBJS += gpg-interface.o
 LIB_OBJS += graph.o
 LIB_OBJS += grep.o
+LIB_OBJS += gvfs.o
 LIB_OBJS += hash-lookup.o
 LIB_OBJS += hashmap.o
 LIB_OBJS += help.o

apply.c

@@ -3346,6 +3346,24 @@ static int checkout_target(struct index_state *istate,
 {
 	struct checkout costate = CHECKOUT_INIT;
 
+	/*
+	 * Do not checkout the entry if the skipworktree bit is set
+	 *
+	 * Both callers of this method (check_preimage and load_current)
+	 * check for the existance of the file before calling this
+	 * method so we know that the file doesn't exist at this point
+	 * and we don't need to perform that check again here.
+	 * We just need to check the skip-worktree and return.
+	 *
+	 * This is to prevent git from creating a file in the
+	 * working directory that has the skip-worktree bit on,
+	 * then updating the index from the patch and not keeping
+	 * the working directory version up to date with what it
+	 * changed the index version to be.
+	 */
+	if (ce_skip_worktree(ce))
+		return 0;
+
 	costate.refresh_cache = 1;
 	costate.istate = istate;
 	if (checkout_entry(ce, &costate, NULL, NULL) ||

builtin/gc.c

@@ -12,6 +12,7 @@
 
 #include "builtin.h"
 #include "repository.h"
+#include "gvfs.h"
 #include "config.h"
 #include "tempfile.h"
 #include "lockfile.h"
@@ -597,6 +598,9 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 	if (quiet)
 		strvec_push(&repack, "-q");
 
+	if ((!auto_gc || (auto_gc && gc_auto_threshold > 0)) && gvfs_config_is_set(GVFS_BLOCK_COMMANDS))
+		die(_("'git gc' is not supported on a GVFS repo"));
+
 	if (auto_gc) {
 		/*
 		 * Auto-gc should be least intrusive as possible.

builtin/update-index.c

@@ -5,6 +5,7 @@
  */
 #define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
+#include "gvfs.h"
 #include "bulk-checkin.h"
 #include "config.h"
 #include "lockfile.h"
@@ -1137,7 +1138,13 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 	argc = parse_options_end(&ctx);
 
 	getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
+	if (mark_skip_worktree_only && gvfs_config_is_set(GVFS_BLOCK_COMMANDS))
+		die(_("modifying the skip worktree bit is not supported on a GVFS repo"));
+
 	if (preferred_index_format) {
+		if (preferred_index_format != 4 && gvfs_config_is_set(GVFS_BLOCK_COMMANDS))
+			die(_("changing the index version is not supported on a GVFS repo"));
+
 		if (preferred_index_format < INDEX_FORMAT_LB ||
 		    INDEX_FORMAT_UB < preferred_index_format)
 			die("index-version %d not in range: %d..%d",
@@ -1175,6 +1182,9 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 	/* by now we must have added all of the new objects */
 	unplug_bulk_checkin();
 	if (split_index > 0) {
+		if (gvfs_config_is_set(GVFS_BLOCK_COMMANDS))
+			die(_("split index is not supported on a GVFS repo"));
+
 		if (git_config_get_split_index() == 0)
 			warning(_("core.splitIndex is set to false; "
 				  "remove or change it, if you really want to "

cache-tree.c

@@ -422,7 +422,29 @@ static int update_one(struct cache_tree *it,
 			continue;
 
 		strbuf_grow(&buffer, entlen + 100);
-		strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
+
+		switch (mode) {
+		case 0100644:
+			strbuf_add(&buffer, "100644 ", 7);
+			break;
+		case 0100664:
+			strbuf_add(&buffer, "100664 ", 7);
+			break;
+		case 0100755:
+			strbuf_add(&buffer, "100755 ", 7);
+			break;
+		case 0120000:
+			strbuf_add(&buffer, "120000 ", 7);
+			break;
+		case 0160000:
+			strbuf_add(&buffer, "160000 ", 7);
+			break;
+		default:
+			strbuf_addf(&buffer, "%o ", mode);
+			break;
+		}
+		strbuf_add(&buffer, path + baselen, entlen);
+		strbuf_addch(&buffer, '\0');
 		strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 
 #if DEBUG_CACHE_TREE

git.c

@@ -1,10 +1,12 @@
 #include "builtin.h"
+#include "gvfs.h"
 #include "config.h"
 #include "exec-cmd.h"
 #include "help.h"
 #include "run-command.h"
 #include "alias.h"
 #include "shallow.h"
+#include "dir.h"
 
 #define RUN_SETUP		(1<<0)
 #define RUN_SETUP_GENTLY	(1<<1)
@@ -17,6 +19,7 @@
 #define SUPPORT_SUPER_PREFIX	(1<<4)
 #define DELAY_PAGER_CONFIG	(1<<5)
 #define NO_PARSEOPT		(1<<6) /* parse-options is not used */
+#define BLOCK_ON_GVFS_REPO	(1<<7) /* command not allowed in GVFS repos */
 
 struct cmd_struct {
 	const char *cmd;
@@ -416,6 +419,64 @@ static int handle_alias(int *argcp, const char ***argv)
 	return ret;
 }
 
+/* Runs pre/post-command hook */
+static struct strvec sargv = STRVEC_INIT;
+static int run_post_hook = 0;
+static int exit_code = -1;
+
+static int run_pre_command_hook(const char **argv)
+{
+	char *lock;
+	int ret = 0;
+
+	/*
+	 * Ensure the global pre/post command hook is only called for
+	 * the outer command and not when git is called recursively
+	 * or spawns multiple commands (like with the alias command)
+	 */
+	lock = getenv("COMMAND_HOOK_LOCK");
+	if (lock && !strcmp(lock, "true"))
+		return 0;
+	setenv("COMMAND_HOOK_LOCK", "true", 1);
+
+	/* call the hook proc */
+	strvec_pushv(&sargv, argv);
+	strvec_pushf(&sargv, "--git-pid=%"PRIuMAX, (uintmax_t)getpid());
+	ret = run_hook_strvec(NULL, "pre-command", &sargv);
+
+	if (!ret)
+		run_post_hook = 1;
+	return ret;
+}
+
+static int run_post_command_hook(void)
+{
+	char *lock;
+	int ret = 0;
+
+	/*
+	 * Only run post_command if pre_command succeeded in this process
+	 */
+	if (!run_post_hook)
+		return 0;
+	lock = getenv("COMMAND_HOOK_LOCK");
+	if (!lock || strcmp(lock, "true"))
+		return 0;
+
+	strvec_pushf(&sargv, "--exit_code=%u", exit_code);
+	ret = run_hook_strvec(NULL, "post-command", &sargv);
+
+	run_post_hook = 0;
+	strvec_clear(&sargv);
+	setenv("COMMAND_HOOK_LOCK", "false", 1);
+	return ret;
+}
+
+static void post_command_hook_atexit(void)
+{
+	run_post_command_hook();
+}
+
 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 {
 	int status, help;
@@ -455,18 +516,26 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 	if (!help && p->option & NEED_WORK_TREE)
 		setup_work_tree();
 
+	if (!help && p->option & BLOCK_ON_GVFS_REPO && gvfs_config_is_set(GVFS_BLOCK_COMMANDS))
+		die("'git %s' is not supported on a GVFS repo", p->cmd);
+
+	if (run_pre_command_hook(argv))
+		die("pre-command hook aborted command");
+
 	trace_argv_printf(argv, "trace: built-in: git");
 	trace2_cmd_name(p->cmd);
 	trace2_cmd_list_config();
 	trace2_cmd_list_env_vars();
 
 	validate_cache_entries(the_repository->index);
-	status = p->fn(argc, argv, prefix);
+	exit_code = status = p->fn(argc, argv, prefix);
 	validate_cache_entries(the_repository->index);
 
 	if (status)
 		return status;
 
+	run_post_command_hook();
+
 	/* Somebody closed stdout? */
 	if (fstat(fileno(stdout), &st))
 		return 0;
@@ -534,7 +603,7 @@ static struct cmd_struct commands[] = {
 	{ "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 	{ "for-each-repo", cmd_for_each_repo, RUN_SETUP_GENTLY },
 	{ "format-patch", cmd_format_patch, RUN_SETUP },
-	{ "fsck", cmd_fsck, RUN_SETUP },
+	{ "fsck", cmd_fsck, RUN_SETUP | BLOCK_ON_GVFS_REPO},
 	{ "fsck-objects", cmd_fsck, RUN_SETUP },
 	{ "fsmonitor--daemon", cmd_fsmonitor__daemon, RUN_SETUP },
 	{ "gc", cmd_gc, RUN_SETUP },
@@ -574,7 +643,7 @@ static struct cmd_struct commands[] = {
 	{ "pack-refs", cmd_pack_refs, RUN_SETUP },
 	{ "patch-id", cmd_patch_id, RUN_SETUP_GENTLY | NO_PARSEOPT },
 	{ "pickaxe", cmd_blame, RUN_SETUP },
-	{ "prune", cmd_prune, RUN_SETUP },
+	{ "prune", cmd_prune, RUN_SETUP | BLOCK_ON_GVFS_REPO},
 	{ "prune-packed", cmd_prune_packed, RUN_SETUP },
 	{ "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 	{ "push", cmd_push, RUN_SETUP },
@@ -586,7 +655,7 @@ static struct cmd_struct commands[] = {
 	{ "remote", cmd_remote, RUN_SETUP },
 	{ "remote-ext", cmd_remote_ext, NO_PARSEOPT },
 	{ "remote-fd", cmd_remote_fd, NO_PARSEOPT },
-	{ "repack", cmd_repack, RUN_SETUP },
+	{ "repack", cmd_repack, RUN_SETUP | BLOCK_ON_GVFS_REPO },
 	{ "replace", cmd_replace, RUN_SETUP },
 	{ "rerere", cmd_rerere, RUN_SETUP },
 	{ "reset", cmd_reset, RUN_SETUP },
@@ -606,7 +675,7 @@ static struct cmd_struct commands[] = {
 	{ "stash", cmd_stash, RUN_SETUP | NEED_WORK_TREE },
 	{ "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 	{ "stripspace", cmd_stripspace },
-	{ "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },
+	{ "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT | BLOCK_ON_GVFS_REPO },
 	{ "switch", cmd_switch, RUN_SETUP | NEED_WORK_TREE },
 	{ "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 	{ "tag", cmd_tag, RUN_SETUP | DELAY_PAGER_CONFIG },
@@ -624,7 +693,7 @@ static struct cmd_struct commands[] = {
 	{ "verify-tag", cmd_verify_tag, RUN_SETUP },
 	{ "version", cmd_version },
 	{ "whatchanged", cmd_whatchanged, RUN_SETUP },
-	{ "worktree", cmd_worktree, RUN_SETUP | NO_PARSEOPT },
+	{ "worktree", cmd_worktree, RUN_SETUP | NO_PARSEOPT | BLOCK_ON_GVFS_REPO },
 	{ "write-tree", cmd_write_tree, RUN_SETUP },
 };
 
@@ -745,13 +814,16 @@ static void execv_dashed_external(const char **argv)
 	 */
 	trace_argv_printf(cmd.args.v, "trace: exec:");
 
+	if (run_pre_command_hook(cmd.args.v))
+		die("pre-command hook aborted command");
+
 	/*
 	 * If we fail because the command is not found, it is
 	 * OK to return. Otherwise, we just pass along the status code,
 	 * or our usual generic code if we were not even able to exec
 	 * the program.
 	 */
-	status = run_command(&cmd);
+	exit_code = status = run_command(&cmd);
 
 	/*
 	 * If the child process ran and we are now going to exit, emit a
@@ -762,6 +834,8 @@ static void execv_dashed_external(const char **argv)
 		exit(status);
 	else if (errno != ENOENT)
 		exit(128);
+
+	run_post_command_hook();
 }
 
 static int run_argv(int *argcp, const char ***argv)
@@ -869,6 +943,7 @@ int cmd_main(int argc, const char **argv)
 	}
 
 	trace_command_performance(argv);
+	atexit(post_command_hook_atexit);
 
 	/*
 	 * "git-xxxx" is the same as "git xxxx", but we obviously:
@@ -896,10 +971,14 @@ int cmd_main(int argc, const char **argv)
 	} else {
 		/* The user didn't specify a command; give them help */
 		commit_pager_choice();
+		if (run_pre_command_hook(argv))
+			die("pre-command hook aborted command");
 		printf(_("usage: %s\n\n"), git_usage_string);
 		list_common_cmds_help();
 		printf("\n%s\n", _(git_more_info_string));
-		exit(1);
+		exit_code = 1;
+		run_post_command_hook();
+		exit(exit_code);
 	}
 	cmd = argv[0];