gvfs-helper: create tool to fetch objects using the GVFS Protocol

Create gvfs-helper.  This is a helper tool to use the GVFS Protocol
REST API to fetch objects and configuration data from a GVFS cache-server
or Git server.  This tool uses libcurl to send object requests to either
server.  This tool creates loose objects and/or packfiles.

Create gvfs-helper-client.  This code resides within git proper and
uses the sub-process API to manage gvfs-helper as a long-running background
process.

Signed-off-by: Jeff Hostetler <[email protected]>

Author: jeffhostetler

.gitignore

@@ -72,6 +72,7 @@
 /git-gc
 /git-get-tar-commit-id
 /git-grep
+/git-gvfs-helper
 /git-hash-object
 /git-help
 /git-http-backend

Documentation/config.txt

@@ -369,6 +369,8 @@ include::config/gui.txt[]
 
 include::config/guitool.txt[]
 
+include::config/gvfs.txt[]
+
 include::config/help.txt[]
 
 include::config/http.txt[]

Documentation/config/core.txt

@@ -659,6 +659,9 @@ core.gvfs::
 		flag just blocks them from occurring at all.
 --
 
+core.useGvfsHelper::
+	TODO
+
 core.sparseCheckout::
 	Enable "sparse checkout" feature. If "false", then sparse-checkout
 	is disabled. If "true", then sparse-checkout is enabled with the full

Documentation/config/gvfs.txt

@@ -0,0 +1,5 @@
+gvfs.cache-server::
+	TODO
+
+gvfs.sharedcache::
+	TODO

Makefile

@@ -898,6 +898,7 @@ LIB_OBJS += gpg-interface.o
 LIB_OBJS += graph.o
 LIB_OBJS += grep.o
 LIB_OBJS += gvfs.o
+LIB_OBJS += gvfs-helper-client.o
 LIB_OBJS += hashmap.o
 LIB_OBJS += linear-assignment.o
 LIB_OBJS += help.o
@@ -1359,6 +1360,8 @@ else
 	CURL_LIBCURL += $(shell $(CURL_CONFIG) --libs)
 endif
 
+	PROGRAM_OBJS += gvfs-helper.o
+
 	REMOTE_CURL_PRIMARY = git-remote-http$X
 	REMOTE_CURL_ALIASES = git-remote-https$X git-remote-ftp$X git-remote-ftps$X
 	REMOTE_CURL_NAMES = $(REMOTE_CURL_PRIMARY) $(REMOTE_CURL_ALIASES)
@@ -2469,6 +2472,10 @@ $(REMOTE_CURL_PRIMARY): remote-curl.o http.o http-walker.o GIT-LDFLAGS $(GITLIBS
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
 		$(CURL_LIBCURL) $(EXPAT_LIBEXPAT) $(LIBS)
 
+git-gvfs-helper$X: gvfs-helper.o http.o GIT-LDFLAGS $(GITLIBS)
+	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+		$(CURL_LIBCURL) $(EXPAT_LIBEXPAT) $(LIBS)
+
 $(LIB_FILE): $(LIB_OBJS)
 	$(QUIET_AR)$(RM) $@ && $(AR) $(ARFLAGS) $@ $^
 

builtin/checkout.c

@@ -27,6 +27,7 @@
 #include "wt-status.h"
 #include "xdiff-interface.h"
 #include "packfile.h"
+#include "gvfs-helper-client.h"
 
 static const char * const checkout_usage[] = {
 	N_("git checkout [<options>] <branch>"),
@@ -1033,6 +1034,13 @@ static int switch_branches(const struct checkout_opts *opts,
 	int flag, writeout_error = 0;
 	int do_merge = 1;
 
+#if 0
+	ghc__pre_checkout_commit(the_repository,
+				 new_branch_info->commit,
+				 opts->show_progress);
+	exit(1);
+#endif
+
 	trace2_cmd_mode("branch");
 
 	memset(&old_branch_info, 0, sizeof(old_branch_info));

builtin/index-pack.c

@@ -1352,7 +1352,7 @@ static void fix_unresolved_deltas(struct hashfile *f)
 		sorted_by_pos[i] = &ref_deltas[i];
 	QSORT(sorted_by_pos, nr_ref_deltas, delta_pos_compare);
 
-	if (repository_format_partial_clone) {
+	if (repository_format_partial_clone || core_use_gvfs_helper) {
 		/*
 		 * Prefetch the delta bases.
 		 */

cache.h

@@ -893,6 +893,9 @@ extern int precomposed_unicode;
 extern int protect_hfs;
 extern int protect_ntfs;
 extern const char *core_fsmonitor;
+extern int core_use_gvfs_helper;
+extern const char *gvfs_cache_server_url;
+extern const char *gvfs_shared_cache_pathname;
 
 int core_apply_sparse_checkout;
 int core_sparse_checkout_cone;

config.c

@@ -21,6 +21,7 @@
 #include "color.h"
 #include "refs.h"
 #include "gvfs.h"
+#include "transport.h"
 
 struct config_source {
 	struct config_source *prev;
@@ -1365,6 +1366,11 @@ static int git_default_core_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (!strcmp(var, "core.usegvfshelper")) {
+		core_use_gvfs_helper = git_config_bool(var, value);
+		return 0;
+	}
+
 	if (!strcmp(var, "core.sparsecheckout")) {
 		/* virtual file system relies on the sparse checkout logic so force it on */
 		if (core_virtualfilesystem)
@@ -1495,6 +1501,25 @@ static int git_default_mailmap_config(const char *var, const char *value)
 	return 0;
 }
 
+static int git_default_gvfs_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "gvfs.cache-server")) {
+		const char *v2 = NULL;
+
+		if (!git_config_string(&v2, var, value) && v2 && *v2)
+			gvfs_cache_server_url = transport_anonymize_url(v2);
+		free((char*)v2);
+		return 0;
+	}
+
+	if (!strcmp(var, "gvfs.sharedcache") && value && *value) {
+		git_config_string(&gvfs_shared_cache_pathname, var, value);
+		return 0;
+	}
+
+	return 0;
+}
+
 int git_default_config(const char *var, const char *value, void *cb)
 {
 	if (starts_with(var, "core."))
@@ -1541,6 +1566,9 @@ int git_default_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (starts_with(var, "gvfs."))
+		return git_default_gvfs_config(var, value);
+
 	/* Add other config variables here and to Documentation/config.txt. */
 	return 0;
 }

diff.c

@@ -6499,7 +6499,7 @@ static void add_if_missing(struct repository *r,
 void diffcore_std(struct diff_options *options)
 {
 	if (options->repo == the_repository &&
-	    repository_format_partial_clone) {
+	    (repository_format_partial_clone || core_use_gvfs_helper)) {
 		/*
 		 * Prefetch the diff pairs that are about to be flushed.
 		 */