[libc] Add implementations of fopen, flose, fread, fwrite and fseek.

[sivachandra]

Summary

A follow up patch will add feof and ferror.

[michaelrj]

libc/src/stdio/fopen.h

16

why does this need to specifically be a global namespace FILE?

libc/src/stdio/fseek.h

16

the other FILEs are specifically global, if that is necessary then this one should be too.

[sivachandra]

Qualify all uses of FILE with "::".

[sivachandra]

libc/src/stdio/fopen.h

16

To make it absolutely clear that we are indeed referring to the public FILE type and not one in the namespace __llvm_libc. We don't have one in __llvm_libc, but qualification makes it clear.

libc/src/stdio/fseek.h

16

Add :: to all references to FILE in src/stdio.

libc/config/linux/x86_64/entrypoints.txt

list(APPEND TARGET_LIBC_ENTRYPOINTS
 
     # stdlib.h entrypoints
     libc.src.stdlib._Exit
     # libc.src.stdlib.abort
     libc.src.stdlib.atexit
     libc.src.stdlib.exit
     libc.src.stdlib.getenv
 
+    # stdio.h entrypoints
+    libc.src.stdio.fclose
+    libc.src.stdio.fopen
+    libc.src.stdio.fread
+    libc.src.stdio.fseek
+    libc.src.stdio.fwrite
+
     # signal.h entrypoints
     # TODO: Enable signal.h entrypoints after fixing signal.h
     # libc.src.signal.raise
     # libc.src.signal.sigaction
     # libc.src.signal.sigdelset
     # libc.src.signal.sigaddset
     # libc.src.signal.sigemptyset
     # libc.src.signal.sigprocmask

libc/spec/stdc.td

HeaderSpec StdIO = HeaderSpec<
       [], // Macros
       [ // Types
           SizeTType,
           FILE,
       ],
       [], // Enumerations
       [
           FunctionSpec<
+              "fclose",
+              RetValSpec<IntType>,
+              [ArgSpec<FILEPtr>]
+          >,
+          FunctionSpec<
+              "fopen",
+              RetValSpec<FILEPtr>,
+              [ArgSpec<ConstCharPtr>,
+               ArgSpec<ConstCharPtr>]
+          >,
+          FunctionSpec<
+              "fread",
+              RetValSpec<SizeTType>,
+              [ArgSpec<VoidRestrictedPtr>,
+               ArgSpec<SizeTType>,
+               ArgSpec<SizeTType>,
+               ArgSpec<FILERestrictedPtr>]
+          >,
+          FunctionSpec<
+              "fseek",
+              RetValSpec<IntType>,
+              [ArgSpec<FILEPtr>,
+               ArgSpec<LongType>,
+               ArgSpec<IntType>]
+          >,
+          FunctionSpec<
               "fwrite",
               RetValSpec<SizeTType>,
               [ArgSpec<ConstVoidRestrictedPtr>,
                ArgSpec<SizeTType>,
                ArgSpec<SizeTType>,
                ArgSpec<FILERestrictedPtr>]
           >,
       ]
   >;
 
   HeaderSpec StdLib = HeaderSpec<
       "stdlib.h",
       [], // Macros
       [

libc/src/stdio/CMakeLists.txt

 add_entrypoint_object(
+  fopen
+  SRCS
+    fopen.cpp
+  HDRS
+    fopen.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
+  fclose
+  SRCS
+    fclose.cpp
+  HDRS
+    fclose.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
+  fread
+  SRCS
+    fread.cpp
+  HDRS
+    fread.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
   fwrite
   SRCS
     fwrite.cpp
   HDRS
     fwrite.h
   DEPENDS
-    libc.src.threads.mtx_lock
-    libc.src.threads.mtx_unlock
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
+  fseek
+  SRCS
+    fseek.cpp
+  HDRS
+    fseek.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
 )

libc/src/stdio/fclose.h

-//===-- Internal definition of FILE -----------------------------*- C++ -*-===//
+//===-- Implementation header of fclose -------------------------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_STDIO_FILE_H
-#define LLVM_LIBC_SRC_STDIO_FILE_H
+#ifndef LLVM_LIBC_SRC_STDIO_FCLOSE_H
+#define LLVM_LIBC_SRC_STDIO_FCLOSE_H
 
-#include "include/threads.h"
-#include <stddef.h>
+#include <stdio.h>
 
 namespace __llvm_libc {
 
-struct FILE {
-  mtx_t lock;
-
-  using write_function_t = size_t(FILE *, const char *, size_t);
-
-  write_function_t *write;
-};
+int fclose(::FILE *stream);
 
 } // namespace __llvm_libc
 
-#endif // LLVM_LIBC_SRC_STDIO_FILE_H
+#endif // LLVM_LIBC_SRC_STDIO_FCLOSE_H

libc/src/stdio/fclose.cpp

+//===-- Implementation of fclose ------------------------------------------===//
+//
+// 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/fclose.h"
+#include "src/__support/File/file.h"
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, fclose, (::FILE * stream)) {
+  return reinterpret_cast<__llvm_libc::File *>(stream)->close();
+}
+
+} // namespace __llvm_libc

libc/src/stdio/fopen.h

-//===-- Internal definition of FILE -----------------------------*- C++ -*-===//
+//===-- Implementation header of fopen --------------------------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_STDIO_FILE_H
-#define LLVM_LIBC_SRC_STDIO_FILE_H
+#ifndef LLVM_LIBC_SRC_STDIO_FOPEN_H
+#define LLVM_LIBC_SRC_STDIO_FOPEN_H
 
-#include "include/threads.h"
-#include <stddef.h>
+#include <stdio.h>
 
 namespace __llvm_libc {
 
-struct FILE {
-  mtx_t lock;
-
-  using write_function_t = size_t(FILE *, const char *, size_t);
-
-  write_function_t *write;
-};
+::FILE *fopen(const char *__restrict name, const char *__restrict mode);
 
 } // namespace __llvm_libc
 
-#endif // LLVM_LIBC_SRC_STDIO_FILE_H
+#endif // LLVM_LIBC_SRC_STDIO_FOPEN_H

libc/src/stdio/fopen.cpp

+//===-- Implementation of fopen -------------------------------------------===//
+//
+// 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/fopen.h"
+#include "src/__support/File/file.h"
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(::FILE *, fopen,
+                   (const char *__restrict name, const char *__restrict mode)) {
+  return reinterpret_cast<::FILE *>(__llvm_libc::openfile(name, mode));
+}
+
+} // namespace __llvm_libc

libc/src/stdio/fread.h

-//===-- Internal definition of FILE -----------------------------*- C++ -*-===//
+//===-- Implementation header of fread --------------------------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_STDIO_FILE_H
-#define LLVM_LIBC_SRC_STDIO_FILE_H
+#ifndef LLVM_LIBC_SRC_STDIO_FREAD_H
+#define LLVM_LIBC_SRC_STDIO_FREAD_H
 
-#include "include/threads.h"
-#include <stddef.h>
+#include <stdio.h>
 
 namespace __llvm_libc {
 
-struct FILE {
-  mtx_t lock;
-
-  using write_function_t = size_t(FILE *, const char *, size_t);
-
-  write_function_t *write;
-};
+size_t fread(void *__restrict buffer, size_t size, size_t nmemb,
+             ::FILE *stream);
 
 } // namespace __llvm_libc
 
-#endif // LLVM_LIBC_SRC_STDIO_FILE_H
+#endif // LLVM_LIBC_SRC_STDIO_FREAD_H

libc/src/stdio/fread.cpp

+//===-- Implementation of fread -------------------------------------------===//
+//
+// 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/fread.h"
+#include "src/__support/File/file.h"
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(size_t, fread,
+                   (void *__restrict buffer, size_t size, size_t nmemb,
+                    ::FILE *stream)) {
+  return reinterpret_cast<__llvm_libc::File *>(stream)->read(buffer,
+                                                             size * nmemb);
+}
+
+} // namespace __llvm_libc

libc/src/stdio/fseek.h

-//===-- Internal definition of FILE -----------------------------*- C++ -*-===//
+//===-- Implementation header of fseek --------------------------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_STDIO_FILE_H
-#define LLVM_LIBC_SRC_STDIO_FILE_H
+#ifndef LLVM_LIBC_SRC_STDIO_FSEEK_H
+#define LLVM_LIBC_SRC_STDIO_FSEEK_H
 
-#include "include/threads.h"
-#include <stddef.h>
+#include <stdio.h>
 
 namespace __llvm_libc {
 
-struct FILE {
-  mtx_t lock;
-
-  using write_function_t = size_t(FILE *, const char *, size_t);
-
-  write_function_t *write;
-};
+int fseek(::FILE *stream, long offset, int whence);
 
 } // namespace __llvm_libc
 
-#endif // LLVM_LIBC_SRC_STDIO_FILE_H
+#endif // LLVM_LIBC_SRC_STDIO_FSEEK_H

libc/src/stdio/fseek.cpp

+//===-- Implementation of fseek -------------------------------------------===//
+//
+// 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/fseek.h"
+#include "src/__support/File/file.h"
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, fseek, (::FILE * stream, long offset, int whence)) {
+  return reinterpret_cast<__llvm_libc::File *>(stream)->seek(offset, whence);
+}
+
+} // namespace __llvm_libc

libc/src/stdio/fwrite.h

 //===-- Implementation header of fwrite -------------------------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_LIBC_SRC_STDIO_FWRITE_H
 #define LLVM_LIBC_SRC_STDIO_FWRITE_H
 
-#include "src/stdio/FILE.h"
-#include <stddef.h>
+#include <stdio.h>
 
 namespace __llvm_libc {
 
-size_t fwrite(const void *__restrict ptr, size_t size, size_t nmeb,
-              __llvm_libc::FILE *__restrict stream);
+size_t fwrite(const void *__restrict ptr, size_t size, size_t nmemb,
+              ::FILE *__restrict stream);
 
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_STDIO_FWRITE_H

libc/src/stdio/fwrite.cpp

-//===-- Implementation of fwrite and fwrite_unlocked ------------*- C++ -*-===//
+//===-- Implementation of fwrite ------------------------------------------===//
 //
 // 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/fwrite.h"
-#include "src/stdio/FILE.h"
-#include "src/threads/mtx_lock.h"
-#include "src/threads/mtx_unlock.h"
+#include "src/__support/File/file.h"
 
-namespace __llvm_libc {
+#include <stdio.h>
 
-size_t fwrite_unlocked(const void *__restrict ptr, size_t size, size_t nmeb,
-                       __llvm_libc::FILE *__restrict stream) {
-  return stream->write(stream, reinterpret_cast<const char *>(ptr),
-                       size * nmeb);
-}
+namespace __llvm_libc {
 
-size_t fwrite(const void *__restrict ptr, size_t size, size_t nmeb,
-              __llvm_libc::FILE *__restrict stream) {
-  __llvm_libc::mtx_lock(&stream->lock);
-  size_t written = fwrite_unlocked(ptr, size, nmeb, stream);
-  __llvm_libc::mtx_unlock(&stream->lock);
-  return written;
+LLVM_LIBC_FUNCTION(size_t, fwrite,
+                   (const void *__restrict buffer, size_t size, size_t nmemb,
+                    ::FILE *stream)) {
+  return reinterpret_cast<__llvm_libc::File *>(stream)->write(buffer,
+                                                              size * nmemb);
 }
 
 } // namespace __llvm_libc

libc/test/src/stdio/CMakeLists.txt

 add_libc_testsuite(libc_stdio_unittests)
 
 add_libc_unittest(
-  fwrite_test
+  fileop_test
   SUITE
     libc_stdio_unittests
   SRCS
-    fwrite_test.cpp
+    fileop_test.cpp
   DEPENDS
+    libc.src.stdio.fclose
+    libc.src.stdio.fopen
+    libc.src.stdio.fread
+    libc.src.stdio.fseek
     libc.src.stdio.fwrite
 )
+
+add_subdirectory(testdata)

libc/test/src/stdio/fileop_test.cpp

+//===-- Unittests for file operations like fopen, flcose etc --------------===//
+//
+// 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/fclose.h"
+#include "src/stdio/fopen.h"
+#include "src/stdio/fread.h"
+#include "src/stdio/fseek.h"
+#include "src/stdio/fwrite.h"
+#include "utils/UnitTest/Test.h"
+
+#include <stdio.h>
+
+TEST(LlvmLibcStdio, SimpleOperations) {
+  constexpr char FILENAME[] = "testdata/simple_operations.test";
+  ::FILE *file = __llvm_libc::fopen(FILENAME, "w");
+  ASSERT_FALSE(file == nullptr);
+  constexpr char CONTENT[] = "1234567890987654321";
+  ASSERT_EQ(sizeof(CONTENT) - 1,
+            __llvm_libc::fwrite(CONTENT, 1, sizeof(CONTENT) - 1, file));
+  ASSERT_EQ(0, __llvm_libc::fclose(file));
+
+  file = __llvm_libc::fopen(FILENAME, "r");
+  ASSERT_FALSE(file == nullptr);
+
+  constexpr size_t READ_SIZE = 5;
+  char data[READ_SIZE];
+  data[READ_SIZE - 1] = '\0';
+  ASSERT_EQ(__llvm_libc::fread(data, 1, READ_SIZE - 1, file), READ_SIZE - 1);
+  ASSERT_STREQ(data, "1234");
+  ASSERT_EQ(__llvm_libc::fseek(file, 5, SEEK_CUR), 0);
+  ASSERT_EQ(__llvm_libc::fread(data, 1, READ_SIZE - 1, file), READ_SIZE - 1);
+  ASSERT_STREQ(data, "0987");
+  ASSERT_EQ(__llvm_libc::fseek(file, -5, SEEK_CUR), 0);
+  ASSERT_EQ(__llvm_libc::fread(data, 1, READ_SIZE - 1, file), READ_SIZE - 1);
+  ASSERT_STREQ(data, "9098");
+
+  ASSERT_EQ(__llvm_libc::fclose(file), 0);
+}

libc/test/src/stdio/fwrite_test.cpp

-//===-- Unittests for fwrite ----------------------------------------------===//
-//
-// 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/__support/CPP/Array.h"
-#include "src/stdio/FILE.h"
-#include "src/stdio/fwrite.h"
-#include "utils/UnitTest/Test.h"
-
-TEST(LlvmLibcStdio, FWriteBasic) {
-  struct StrcpyFile : __llvm_libc::FILE {
-    char *buf;
-  } f;
-  char array[6];
-  f.buf = array;
-  f.write = +[](__llvm_libc::FILE *file, const char *ptr, size_t size) {
-    StrcpyFile *strcpyFile = static_cast<StrcpyFile *>(file);
-    for (size_t i = 0; i < size; ++i)
-      strcpyFile->buf[i] = ptr[i];
-    return size;
-  };
-  EXPECT_EQ(fwrite("hello", 1, 6, &f), 6UL);
-  EXPECT_STREQ(array, "hello");
-}