Merge advanced VFS-specific features

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

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

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

BRANCHES.md

@@ -0,0 +1,53 @@
+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. master
+
+    This will track the Git for Windows repository master branch
+
+2. vfs
+
+    Would like to use this branch as an ever-green branch that continually rebases the VFSForGit changes onto a windows ever-green branch that is on the core/master, so that we can detect when the patches for VFSForGit have issues or if we have a new version patches sent upstream git we can regenerate this branch.
+
+3. vs/master
+
+    This tracks with the Git for Windows repository vs/master branch and are the generated files for using a Visual Studio solution.
+
+4. 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-2.20.0
+    vfs-2.20.1
+    ```
+
+    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.
+
+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.
+
+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

@@ -890,6 +890,7 @@ LIB_OBJS += gettext.o
 LIB_OBJS += gpg-interface.o
 LIB_OBJS += graph.o
 LIB_OBJS += grep.o
+LIB_OBJS += gvfs.o
 LIB_OBJS += hashmap.o
 LIB_OBJS += help.o
 LIB_OBJS += hex.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.h

@@ -220,6 +220,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix);
 int cmd_tar_tree(int argc, const char **argv, const char *prefix);
 int cmd_unpack_file(int argc, const char **argv, const char *prefix);
 int cmd_unpack_objects(int argc, const char **argv, const char *prefix);
+int cmd_update(int argc, const char **argv, const char *prefix);
 int cmd_update_index(int argc, const char **argv, const char *prefix);
 int cmd_update_ref(int argc, const char **argv, const char *prefix);
 int cmd_update_server_info(int argc, const char **argv, const char *prefix);

builtin/gc.c

@@ -28,6 +28,7 @@
 #include "blob.h"
 #include "tree.h"
 #include "promisor-remote.h"
+#include "gvfs.h"
 
 #define FAILED_RUN "failed to run %s"
 
@@ -585,6 +586,9 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 	if (quiet)
 		argv_array_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/reset.c

@@ -27,6 +27,7 @@
 #include "submodule-config.h"
 #include "strbuf.h"
 #include "quote.h"
+#include "dir.h"
 
 #define REFRESH_INDEX_DELAY_WARNING_IN_MS (2 * 1000)
 
@@ -130,12 +131,45 @@ static void update_index_from_diff(struct diff_queue_struct *q,
 		struct diff_options *opt, void *data)
 {
 	int i;
+	int pos;
 	int intent_to_add = *(int *)data;
 
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filespec *one = q->queue[i]->one;
+		struct diff_filespec *two = q->queue[i]->two;
 		int is_missing = !(one->mode && !is_null_oid(&one->oid));
+		int was_missing = !two->mode && is_null_oid(&two->oid);
 		struct cache_entry *ce;
+		struct cache_entry *ceBefore;
+		struct checkout state = CHECKOUT_INIT;
+
+		/*
+		 * When using the sparse-checkout feature the cache entries that are
+		 * added here will not have the skip-worktree bit set.
+		 * Without this code there is data that is lost because the files that
+		 * would normally be in the working directory are not there and show as
+		 * deleted for the next status or in the case of added files just disappear.
+		 * We need to create the previous version of the files in the working
+		 * directory so that they will have the right content and the next
+		 * status call will show modified or untracked files correctly.
+		 */
+		if (core_apply_sparse_checkout && !file_exists(two->path))
+		{
+			pos = cache_name_pos(two->path, strlen(two->path));
+			if ((pos >= 0 && ce_skip_worktree(active_cache[pos])) && (is_missing || !was_missing))
+			{
+				state.force = 1;
+				state.refresh_cache = 1;
+				state.istate = &the_index;
+				ceBefore = make_cache_entry(&the_index, two->mode, &two->oid, two->path,
+					0, 0);
+				if (!ceBefore)
+					die(_("make_cache_entry failed for path '%s'"),
+						two->path);
+
+				checkout_entry(ceBefore, &state, NULL, NULL);
+			}
+		}
 
 		if (is_missing && !intent_to_add) {
 			remove_file_from_cache(one->path);

builtin/update-index.c

@@ -18,6 +18,7 @@
 #include "dir.h"
 #include "split-index.h"
 #include "fsmonitor.h"
+#include "gvfs.h"
 
 /*
  * Default to not allowing changes to the list of files. The
@@ -1133,7 +1134,13 @@ 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",
@@ -1169,6 +1176,9 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 	}
 
 	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

@@ -398,7 +398,29 @@ 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