tests: test that largefiles can be read through the tree API

src/posix.c

@@ -216,6 +216,23 @@ int p_write(git_file fd, const void *buf, size_t cnt)
 	return 0;
 }
 
+int p_fallocate(int fd, off_t offset, off_t len)
+{
+#ifdef __APPLE__
+	fstore_t prealloc;
+
+	memset(&prealloc, 0, sizeof(prealloc));
+	prealloc.fst_flags  = F_ALLOCATEALL;
+	prealloc.fst_posmode = F_PEOFPOSMODE;
+	prealloc.fst_offset = offset;
+	prealloc.fst_length = len;
+
+	return fcntl(fd, F_PREALLOCATE, &prealloc);
+#else
+	return posix_fallocate(fd, offset, len);
+#endif
+}
+
 #ifdef NO_MMAP
 
 #include "map.h"

src/posix.h

@@ -115,6 +115,7 @@ extern int p_open(const char *path, int flags, ...);
 extern int p_creat(const char *path, mode_t mode);
 extern int p_getcwd(char *buffer_out, size_t size);
 extern int p_rename(const char *from, const char *to);
+extern int p_fallocate(int fd, off_t offset, off_t len);
 
 extern int git__page_size(size_t *page_size);
 extern int git__mmap_alignment(size_t *page_size);

src/win32/posix_w32.c

@@ -516,6 +516,12 @@ int p_creat(const char *path, mode_t mode)
 	return p_open(path, O_WRONLY | O_CREAT | O_TRUNC, mode);
 }
 
+int p_fallocate(int fd, off_t offset, off_t len)
+{
+	error = ENOSYS;
+	return -1;
+}
+
 int p_utimes(const char *path, const struct p_timeval times[2])
 {
 	git_win32_path wpath;

tests/object/tree/read.c

@@ -73,3 +73,56 @@ void test_object_tree_read__two(void)
 	git_object_free(obj);
 	git_tree_free(tree);
 }
+
+#define BIGFILE "bigfile"
+#define BIGFILE_SIZE (off_t)4 * 1024 * 1024 * 1024 /* 4 GiB */
+
+void test_object_tree_read__largefile(void)
+{
+	git_reference *ref;
+	git_commit *commit;
+	git_tree *tree;
+	git_oid oid;
+	const git_tree_entry *entry;
+	git_object *object;
+	git_buf file = GIT_BUF_INIT;
+	int fd;
+	git_index *idx;
+
+#ifdef GIT_WIN32
+	cl_skip();
+#endif
+
+	if (!cl_is_env_set("GITTEST_INVASIVE_FS_SIZE"))
+		cl_skip();
+
+	cl_git_pass(git_reference_lookup(&ref, g_repo, "refs/heads/master"));
+	cl_git_pass(git_repository_index(&idx, g_repo));
+
+	cl_git_pass(git_buf_puts(&file, git_repository_workdir(g_repo)));
+	cl_git_pass(git_buf_joinpath(&file, file.ptr, BIGFILE));
+
+	fd = p_open(git_buf_cstr(&file), O_CREAT|O_RDWR, 0644);
+	cl_assert_(fd >= 0, "invalid file descriptor");
+
+	cl_must_pass(p_fallocate(fd, 0, BIGFILE_SIZE));
+	cl_must_pass(p_close(fd));
+
+	cl_git_pass(git_index_add_bypath(idx, BIGFILE));
+	cl_repo_commit_from_index(&oid, g_repo, NULL, 0, "bigfile");
+
+	cl_git_pass(git_commit_lookup(&commit, g_repo, &oid));
+	cl_git_pass(git_commit_tree(&tree, commit));
+
+	entry = git_tree_entry_byname(tree, BIGFILE);
+	cl_assert_(entry, "entry was NULL");
+
+	cl_git_pass(git_tree_entry_to_object(&object, g_repo, entry));
+
+	git_buf_dispose(&file);
+	git_object_free(object);
+	git_tree_free(tree);
+	git_index_free(idx);
+	git_commit_free(commit);
+	git_reference_free(ref);
+}