[libc-commits] [libc] [libc] Add the implementation of the fdopen function (PR #94186)

[Michael Jones via libc-commits]

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@@ -0,0 +1,90 @@
+//===-- Unittest for fdopen -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/fdopen.h"
+
+#include "include/llvm-libc-macros/fcntl-macros.h"
+#include "src/errno/libc_errno.h"
+#include "src/fcntl/open.h"
+#include "src/stdio/fclose.h"
+#include "src/stdio/fgets.h"
+#include "src/stdio/fputs.h"
+#include "src/unistd/close.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include <sys/stat.h> // For S_IRWXU
+
+TEST(LlvmLibcStdioFdopenTest, WriteAppendRead) {
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+  LIBC_NAMESPACE::libc_errno = 0;
+  constexpr const char *TEST_FILE_NAME = "testdata/write_read_append.test";
+  auto TEST_FILE = libc_make_test_file_path(TEST_FILE_NAME);
+  int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_TRUNC | O_RDWR, S_IRWXU);
+  auto *fp = LIBC_NAMESPACE::fdopen(fd, "w");
+  ASSERT_ERRNO_SUCCESS();
+  ASSERT_TRUE(nullptr != fp);
+  constexpr const char HELLO[] = "Hello";
+  LIBC_NAMESPACE::fputs(HELLO, fp);
+  LIBC_NAMESPACE::fclose(fp);
+  ASSERT_ERRNO_SUCCESS();
+
+  constexpr const char LLVM[] = "LLVM";
+  int fd2 = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_RDWR);
+  auto *fp2 = LIBC_NAMESPACE::fdopen(fd2, "a");
+  ASSERT_ERRNO_SUCCESS();
+  ASSERT_TRUE(nullptr != fp2);
+  LIBC_NAMESPACE::fputs(LLVM, fp2);
+  LIBC_NAMESPACE::fclose(fp2);
+  ASSERT_ERRNO_SUCCESS();
+
+  int fd3 = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_RDWR);
+  auto *fp3 = LIBC_NAMESPACE::fdopen(fd3, "r");
+  char buffer[10];
+  LIBC_NAMESPACE::fgets(buffer, sizeof(buffer), fp3);
+  EXPECT_EQ('H', buffer[0]);
----------------
michaelrj-google wrote:

instead of checking just two characters you can use `ASSERT_STREQ` to check the whole string at once. You might need to make sure that `buffer` has a null byte at the end for that.

https://github.com/llvm/llvm-project/pull/94186