[libc][NFC] Move the Linux file implementation to a subdirectory

[jhuber6]

Summary

This patch simply moves the special handling for linux files to a
subdirectory. This is done to make it easier in the future to extend
this support to targets (like the GPU) that will have different
dependencies.

[jhuber6]

Return if the directory doesn't exist

[lntue]

libc/src/__support/File/CMakeLists.txt

37

Since the targets are moved to separate sub-folders, shall we drop the prefix ${LIBC_TARGET_OS}_ from the target name?

[jhuber6]

libc/src/__support/File/CMakeLists.txt

37

We could, I was mostly just copying the interface from how we handle OSUtil.

[lntue]

libc/src/__support/File/CMakeLists.txt

37

Can you change it so that it matches other folders' structure?

[jhuber6]

libc/src/__support/File/CMakeLists.txt

37

I thought that's what we have now. For something like OSUtil we have a linux/ subdirectory which provides linux_unit.

[lntue]

libc/src/__support/File/CMakeLists.txt

37

So for example you can see that in OSUtil, each sub-target has io.h or syscall.h instead of target_io.h or target_syscall.h

[jhuber6]

libc/src/__support/File/CMakeLists.txt

37

Well the files are called file.cpp and dir.cpp, it's just the CMake target name that's different, I guess in the off-chance that we'd ever build two of these at one time, like there's a generic version or something.

libc/src/__support/File/CMakeLists.txt

add_object_library(
   HDRS
     dir.h
   DEPENDS
     libc.src.__support.CPP.new
     libc.src.__support.CPP.span
     libc.src.__support.threads.mutex
 )
 
-if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS}_file.cpp)
-  add_object_library(
-    platform_file
-    SRCS
-      ${LIBC_TARGET_OS}_file.cpp
-    DEPENDS
-      .file
-      libc.include.fcntl
-      libc.include.stdio
-      libc.include.sys_syscall
-      libc.src.__support.CPP.new
-      libc.src.__support.OSUtil.osutil
-      libc.src.errno.errno
-      libc.src.__support.error_or
-  )
-endif()
+if(NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+  return()
+endif()
+
+add_subdirectory(${LIBC_TARGET_OS})
+set(target_file libc.src.__support.File.${LIBC_TARGET_OS}.${LIBC_TARGET_OS}_file)
+set(target_dir libc.src.__support.File.${LIBC_TARGET_OS}.${LIBC_TARGET_OS}_dir)
+if((NOT TARGET ${target_file}) OR (NOT TARGET ${target_dir}))
+  return()
+endif()
+
+  ALIAS
+    ${target_file}
+    ${target_file}
 
-if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS}_dir.cpp)
-  add_object_library(
-    platform_dir
-    SRCS
-      ${LIBC_TARGET_OS}_dir.cpp
-    DEPENDS
-      .dir
-      libc.include.fcntl
-      libc.include.sys_syscall
-      libc.src.__support.OSUtil.osutil
-      libc.src.__support.error_or
-      libc.src.errno.errno
-  )
-endif()
+  ALIAS
+    ${target_dir}
+    ${target_dir}

libc/src/__support/File/linux/CMakeLists.txt

+add_object_library(
+  linux_file
+  SRCS
+    file.cpp
+  DEPENDS
+    libc.include.fcntl
+    libc.include.stdio
+    libc.include.sys_syscall
+    libc.src.__support.CPP.new
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+    libc.src.__support.error_or
+    libc.src.__support.File.file
+)
+
+add_object_library(
+  linux_dir
+  SRCS
+    dir.cpp
+  DEPENDS
+    libc.include.fcntl
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.__support.error_or
+    libc.src.errno.errno
+    libc.src.__support.File.dir
+)

libc/src/__support/File/linux/dir.cpp

 //===--- Linux implementation of the Dir helpers --------------------------===//
 //
 // 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 "dir.h"
+#include "src/__support/File/dir.h"
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/error_or.h"
 
 #include <fcntl.h>       // For open flags
 #include <sys/syscall.h> // For syscall numbers
 
 namespace __llvm_libc {

libc/src/__support/File/linux/file.cpp

 //===--- Linux specialization of the File data structure ------------------===//
 //
 // 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 "file.h"
+#include "src/__support/File/file.h"
 
 #include "src/__support/CPP/new.h"
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/errno/libc_errno.h"         // For error macros
 
 #include <fcntl.h> // For mode_t and other flags to the open syscall
 #include <stdio.h>
 #include <sys/syscall.h> // For syscall numbers