Share a createUniqueEntity implementation between unix and windows.

The only extra bit of functionality that had to be exposed for this be be
implemented in Path.cpp is opening a file in rw mode.

llvm-svn: 202005

1 files changed, 71 insertions, 4 deletions

diff --git a/llvm/lib/Support/Path.cpp b/llvm/lib/Support/Path.cpp
index 535ff00bae0..5b8be18db3f 100644
--- a/llvm/lib/Support/Path.cpp
+++ b/llvm/lib/Support/Path.cpp
@@ -27,6 +27,8 @@
 #include <io.h>
 #endif
 
+using namespace llvm;
+
 namespace {
   using llvm::StringRef;
   using llvm::sys::path::is_separator;
@@ -162,10 +164,75 @@ enum FSEntity {
 };
 
 // Implemented in Unix/Path.inc and Windows/Path.inc.
-static llvm::error_code
-createUniqueEntity(const llvm::Twine &Model, int &ResultFD,
-                   llvm::SmallVectorImpl<char> &ResultPath,
-                   bool MakeAbsolute, unsigned Mode, FSEntity Type);
+static error_code TempDir(SmallVectorImpl<char> &result);
+
+static error_code createUniqueEntity(const Twine &Model, int &ResultFD,
+                                     SmallVectorImpl<char> &ResultPath,
+                                     bool MakeAbsolute, unsigned Mode,
+                                     FSEntity Type) {
+  SmallString<128> ModelStorage;
+  Model.toVector(ModelStorage);
+
+  if (MakeAbsolute) {
+    // Make model absolute by prepending a temp directory if it's not already.
+    if (!sys::path::is_absolute(Twine(ModelStorage))) {
+      SmallString<128> TDir;
+      if (error_code EC = TempDir(TDir))
+        return EC;
+      sys::path::append(TDir, Twine(ModelStorage));
+      ModelStorage.swap(TDir);
+    }
+  }
+
+  // From here on, DO NOT modify model. It may be needed if the randomly chosen
+  // path already exists.
+  ResultPath = ModelStorage;
+  // Null terminate.
+  ResultPath.push_back(0);
+  ResultPath.pop_back();
+
+retry_random_path:
+  // Replace '%' with random chars.
+  for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
+    if (ModelStorage[i] == '%')
+      ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
+  }
+
+  // Try to open + create the file.
+  switch (Type) {
+  case FS_File: {
+    if (error_code EC = sys::fs::openFileForWrite(
+            Twine(ResultPath.begin()), ResultFD,
+            sys::fs::F_RW | sys::fs::F_Excl | sys::fs::F_Binary, Mode)) {
+      if (EC == errc::file_exists)
+        goto retry_random_path;
+      return EC;
+    }
+
+    return error_code::success();
+  }
+
+  case FS_Name: {
+    bool Exists;
+    error_code EC = sys::fs::exists(ResultPath.begin(), Exists);
+    if (EC)
+      return EC;
+    if (Exists)
+      goto retry_random_path;
+    return error_code::success();
+  }
+
+  case FS_Dir: {
+    if (error_code EC = sys::fs::create_directory(ResultPath.begin(), false)) {
+      if (EC == errc::file_exists)
+        goto retry_random_path;
+      return EC;
+    }
+    return error_code::success();
+  }
+  }
+  llvm_unreachable("Invalid Type");
+}
 
 namespace llvm {
 namespace sys  {