t: add a test helper to truncate files

In a future commit, we're going to work with some large files which will
be at least 4 GiB in size.  To take advantage of the sparseness
functionality on most Unix systems and avoid running the system out of
disk, it would be convenient to use truncate(2) to simply create a
sparse file of sufficient size.

However, the GNU truncate(1) utility isn't portable, so let's write a
tiny test helper that does the work for us.

Signed-off-by: brian m. carlson <bk2204@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index 5776309365357a5848c5f03214690e75d7deb57c..3a6889d2bc8282c50955ee50358119f6fe5e0a79 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -852,6 +852,7 @@ TEST_BUILTINS_OBJS += test-submodule-nested-repo-config.o
 TEST_BUILTINS_OBJS += test-submodule.o
 TEST_BUILTINS_OBJS += test-subprocess.o
 TEST_BUILTINS_OBJS += test-trace2.o
+TEST_BUILTINS_OBJS += test-truncate.o
 TEST_BUILTINS_OBJS += test-urlmatch-normalization.o
 TEST_BUILTINS_OBJS += test-userdiff.o
 TEST_BUILTINS_OBJS += test-wildmatch.o

diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index abe8a785eb651017ce2336eed7fa3bda06d4658c..9bd223b36514d8ecbdc2b3c12fb03bfc07d4d86e 100644 (file)
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -86,6 +86,7 @@ static struct test_cmd cmds[] = {
        { "submodule-nested-repo-config", cmd__submodule_nested_repo_config },
        { "subprocess", cmd__subprocess },
        { "trace2", cmd__trace2 },
+       { "truncate", cmd__truncate },
        { "userdiff", cmd__userdiff },
        { "urlmatch-normalization", cmd__urlmatch_normalization },
        { "xml-encode", cmd__xml_encode },

diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index ea2672436c9ab56ed544d0a3ff414c366de5fdc0..f41a4d0aa86990210ef29afa70df2395e03f31e5 100644 (file)
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -79,6 +79,7 @@ int cmd__submodule_config(int argc, const char **argv);
 int cmd__submodule_nested_repo_config(int argc, const char **argv);
 int cmd__subprocess(int argc, const char **argv);
 int cmd__trace2(int argc, const char **argv);
+int cmd__truncate(int argc, const char **argv);
 int cmd__userdiff(int argc, const char **argv);
 int cmd__urlmatch_normalization(int argc, const char **argv);
 int cmd__xml_encode(int argc, const char **argv);

diff --git a/t/helper/test-truncate.c b/t/helper/test-truncate.c
new file mode 100644 (file)
index 0000000..3931dea
--- /dev/null
+++ b/t/helper/test-truncate.c
@@ -0,0 +1,25 @@
+#include "test-tool.h"
+#include "git-compat-util.h"
+
+/*
+ * Truncate a file to the given size.
+ */
+int cmd__truncate(int argc, const char **argv)
+{
+       char *p = NULL;
+       uintmax_t sz = 0;
+       int fd = -1;
+
+       if (argc != 3)
+               die("expected filename and size");
+
+       sz = strtoumax(argv[2], &p, 0);
+       if (*p)
+               die("invalid size");
+
+       fd = xopen(argv[1], O_WRONLY | O_CREAT, 0600);
+
+       if (ftruncate(fd, (off_t) sz) < 0)
+               die_errno("failed to truncate file");
+       return 0;
+}