Support/PathV2: Add identify_magic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123548 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/FileSystem.h

@@ -30,6 +30,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/PathV1.h"
 #include "llvm/Support/system_error.h"
 #include <ctime>
 #include <iterator>
@@ -463,6 +464,14 @@ error_code has_magic(const Twine &path, const Twine &magic, bool &result);
 error_code get_magic(const Twine &path, uint32_t len,
                      SmallVectorImpl<char> &result);
 
+/// @brief Get and identify \a path's type based on its content.
+///
+/// @param path Input path.
+/// @param result Set to the type of file, or LLVMFileType::Unknown_FileType.
+/// @results errc::success if result has been successfully set, otherwise a
+///          platform specific error_code.
+error_code identify_magic(const Twine &path, LLVMFileType &result);
+
 /// @brief Is file bitcode?
 ///
 /// @param path Input path.

lib/Archive/Archive.cpp

@@ -116,11 +116,10 @@ bool ArchiveMember::replaceWith(const sys::Path& newFile, std::string* ErrMsg) {
 
   // Get the signature and status info
   const char* signature = (const char*) data;
-  std::string magic;
+  SmallString<4> magic;
   if (!signature) {
-    path.getMagicNumber(magic,4);
+    sys::fs::get_magic(path.str(), magic.capacity(), magic);
     signature = magic.c_str();
-    std::string err;
     const sys::FileStatus *FSinfo = path.getFileStatus(false, ErrMsg);
     if (FSinfo)
       info = *FSinfo;

lib/Archive/ArchiveWriter.cpp

@@ -181,9 +181,11 @@ Archive::addFileBefore(const sys::Path& filePath, iterator where,
     flags |= ArchiveMember::HasPathFlag;
   if (hasSlash || filePath.str().length() > 15)
     flags |= ArchiveMember::HasLongFilenameFlag;
-  std::string magic;
+
-  mbr->path.getMagicNumber(magic,4);
+  sys::LLVMFileType type;
-  switch (sys::IdentifyFileType(magic.c_str(),4)) {
+  if (sys::fs::identify_magic(mbr->path.str(), type))
+    type = sys::Unknown_FileType;
+  switch (type) {
     case sys::Bitcode_FileType:
       flags |= ArchiveMember::BitcodeFlag;
       break;

lib/Support/Path.cpp

@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/Path.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/FileSystem.h"
 #include <cassert>
@@ -141,42 +142,33 @@ sys::IdentifyFileType(const char *magic, unsigned length) {
 
 bool
 Path::isArchive() const {
-  std::string Magic;
+  LLVMFileType type;
-  if (getMagicNumber(Magic, 8))
+  if (fs::identify_magic(str(), type))
-    if (IdentifyFileType(Magic.c_str(), Magic.length()) == Archive_FileType)
+    return false;
-      return true;
+  return type == Archive_FileType;
-  return false;
 }
 
 bool
 Path::isDynamicLibrary() const {
-  std::string Magic;
+  LLVMFileType type;
-  if (getMagicNumber(Magic, 64))
+  if (fs::identify_magic(str(), type))
-    switch (IdentifyFileType(Magic.c_str(),
+    return false;
-                             static_cast<unsigned>(Magic.length()))) {
+  switch (type) {
-      default: return false;
+    default: return false;
-      case Mach_O_FixedVirtualMemorySharedLib_FileType:
+    case Mach_O_FixedVirtualMemorySharedLib_FileType:
-      case Mach_O_DynamicallyLinkedSharedLib_FileType:
+    case Mach_O_DynamicallyLinkedSharedLib_FileType:
-      case Mach_O_DynamicallyLinkedSharedLibStub_FileType:
+    case Mach_O_DynamicallyLinkedSharedLibStub_FileType:
-      case ELF_SharedObject_FileType:
+    case ELF_SharedObject_FileType:
-      case COFF_FileType:  return true;
+    case COFF_FileType:  return true;
-    }
+  }
-
-  return false;
 }
 
 bool
 Path::isObjectFile() const {
-  std::string Magic;
+  LLVMFileType type;
-  if (getMagicNumber(Magic, 64))
+  if (fs::identify_magic(str(), type) || type == Unknown_FileType)
-    if (IdentifyFileType(Magic.c_str(),
+    return false;
-                         static_cast<unsigned>(Magic.length()))
+  return true;
-        != Unknown_FileType) {
-      // Everything in LLVMFileType is currently an object file.
-      return true;
-    }
-
-  return false;
 }
 
 Path
@@ -210,13 +202,10 @@ Path::appendSuffix(StringRef suffix) {
 
 bool
 Path::isBitcodeFile() const {
-  std::string actualMagic;
+  LLVMFileType type;
-  if (!getMagicNumber(actualMagic, 4))
+  if (fs::identify_magic(str(), type))
     return false;
-  LLVMFileType FT =
+  return type == Bitcode_FileType;
-    IdentifyFileType(actualMagic.c_str(),
-                     static_cast<unsigned>(actualMagic.length()));
-  return FT == Bitcode_FileType;
 }
 
 bool Path::hasMagicNumber(StringRef Magic) const {

lib/Support/PathV2.cpp

@@ -703,6 +703,16 @@ error_code has_magic(const Twine &path, const Twine &magic, bool &result) {
   return success;
 }
 
+error_code identify_magic(const Twine &path, LLVMFileType &result) {
+  SmallString<32> Magic;
+  error_code ec = get_magic(path, Magic.capacity(), Magic);
+  if (ec && ec != errc::value_too_large)
+    return ec;
+
+  result = IdentifyFileType(Magic.data(), Magic.size());
+  return success;
+}
+
 namespace {
 error_code remove_all_r(StringRef path, file_type ft, uint32_t &count) {
   if (ft == file_type::directory_file) {