Support/FileSystem: Implement recursive_directory_iterator and make

directory_iterator preserve InputIterator semantics on copy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146200 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 198 insertions, 42 deletions

diff --git a/include/llvm/ADT/IntrusiveRefCntPtr.h b/include/llvm/ADT/IntrusiveRefCntPtr.h
index 8757f00..106daf4 100644
--- a/include/llvm/ADT/IntrusiveRefCntPtr.h
+++ b/include/llvm/ADT/IntrusiveRefCntPtr.h
@@ -156,7 +156,12 @@ namespace llvm {
       other.Obj = Obj;
       Obj = tmp;
     }
-    
+
+    void reset() {
+      release();
+      Obj = 0;
+    }
+
     void resetWithoutRelease() {
       Obj = 0;
     }
diff --git a/include/llvm/Support/FileSystem.h b/include/llvm/Support/FileSystem.h
index a868e5f..42e61dc 100644
--- a/include/llvm/Support/FileSystem.h
+++ b/include/llvm/Support/FileSystem.h
@@ -27,13 +27,16 @@
 #ifndef LLVM_SUPPORT_FILE_SYSTEM_H
 #define LLVM_SUPPORT_FILE_SYSTEM_H
 
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/PathV1.h"
 #include "llvm/Support/system_error.h"
 #include <ctime>
 #include <iterator>
+#include <stack>
 #include <string>
 
 namespace llvm {
@@ -479,76 +482,171 @@ public:
   bool operator>=(const directory_entry& rhs) const;
 };
 
+namespace detail {
+  struct DirIterState;
+
+  error_code directory_iterator_construct(DirIterState&, StringRef);
+  error_code directory_iterator_increment(DirIterState&);
+  error_code directory_iterator_destruct(DirIterState&);
+
+  /// DirIterState - Keeps state for the directory_iterator. It is reference
+  /// counted in order to preserve InputIterator semantics on copy.
+  struct DirIterState : public RefCountedBase<DirIterState> {
+    DirIterState()
+      : IterationHandle(0) {}
+
+    ~DirIterState() {
+      directory_iterator_destruct(*this);
+    }
+
+    intptr_t IterationHandle;
+    directory_entry CurrentEntry;
+  };
+}
+
 /// directory_iterator - Iterates through the entries in path. There is no
 /// operator++ because we need an error_code. If it's really needed we can make
 /// it call report_fatal_error on error.
 class directory_iterator {
-  intptr_t IterationHandle;
-  directory_entry CurrentEntry;
-
-  // Platform implementations implement these functions to handle iteration.
-  friend error_code directory_iterator_construct(directory_iterator &it,
-                                                 StringRef path);
-  friend error_code directory_iterator_increment(directory_iterator &it);
-  friend error_code directory_iterator_destruct(directory_iterator &it);
+  IntrusiveRefCntPtr<detail::DirIterState> State;
 
 public:
-  explicit directory_iterator(const Twine &path, error_code &ec)
-  : IterationHandle(0) {
+  explicit directory_iterator(const Twine &path, error_code &ec) {
+    State = new detail::DirIterState;
     SmallString<128> path_storage;
-    ec = directory_iterator_construct(*this, path.toStringRef(path_storage));
+    ec = detail::directory_iterator_construct(*State,
+            path.toStringRef(path_storage));
   }
 
-  /// Construct end iterator.
-  directory_iterator() : IterationHandle(0) {}
-
-  ~directory_iterator() {
-    directory_iterator_destruct(*this);
+  explicit directory_iterator(const directory_entry &de, error_code &ec) {
+    State = new detail::DirIterState;
+    ec = detail::directory_iterator_construct(*State, de.path());
   }
 
+  /// Construct end iterator.
+  directory_iterator() : State(new detail::DirIterState) {}
+
   // No operator++ because we need error_code.
   directory_iterator &increment(error_code &ec) {
-    ec = directory_iterator_increment(*this);
+    ec = directory_iterator_increment(*State);
     return *this;
   }
 
-  const directory_entry &operator*() const { return CurrentEntry; }
-  const directory_entry *operator->() const { return &CurrentEntry; }
+  const directory_entry &operator*() const { return State->CurrentEntry; }
+  const directory_entry *operator->() const { return &State->CurrentEntry; }
+
+  bool operator==(const directory_iterator &RHS) const {
+    return State->CurrentEntry == RHS.State->CurrentEntry;
+  }
 
   bool operator!=(const directory_iterator &RHS) const {
-    return CurrentEntry != RHS.CurrentEntry;
+    return !(*this == RHS);
   }
   // Other members as required by
   // C++ Std, 24.1.1 Input iterators [input.iterators]
 };
 
+namespace detail {
+  /// RecDirIterState - Keeps state for the recursive_directory_iterator. It is
+  /// reference counted in order to preserve InputIterator semantics on copy.
+  struct RecDirIterState : public RefCountedBase<RecDirIterState> {
+    RecDirIterState()
+      : Level(0)
+      , HasNoPushRequest(false) {}
+
+    std::stack<directory_iterator, std::vector<directory_iterator> > Stack;
+    uint16_t Level;
+    bool HasNoPushRequest;
+  };
+}
+
 /// recursive_directory_iterator - Same as directory_iterator except for it
 /// recurses down into child directories.
 class recursive_directory_iterator {
-  uint16_t  Level;
-  bool HasNoPushRequest;
-  // implementation directory iterator status
+  IntrusiveRefCntPtr<detail::RecDirIterState> State;
 
 public:
-  explicit recursive_directory_iterator(const Twine &path, error_code &ec);
+  recursive_directory_iterator() {}
+  explicit recursive_directory_iterator(const Twine &path, error_code &ec)
+    : State(new detail::RecDirIterState) {
+    State->Stack.push(directory_iterator(path, ec));
+    if (State->Stack.top() == directory_iterator())
+      State.reset();
+  }
   // No operator++ because we need error_code.
-  directory_iterator &increment(error_code &ec);
+  recursive_directory_iterator &increment(error_code &ec) {
+    static const directory_iterator end_itr;
+
+    if (State->HasNoPushRequest)
+      State->HasNoPushRequest = false;
+    else {
+      file_status st;
+      if ((ec = State->Stack.top()->status(st))) return *this;
+      if (is_directory(st)) {
+        State->Stack.push(directory_iterator(*State->Stack.top(), ec));
+        if (ec) return *this;
+        if (State->Stack.top() != end_itr) {
+          ++State->Level;
+          return *this;
+        }
+        State->Stack.pop();
+      }
+    }
+
+    while (!State->Stack.empty()
+           && State->Stack.top().increment(ec) == end_itr) {
+      State->Stack.pop();
+      --State->Level;
+    }
+
+    // Check if we are done. If so, create an end iterator.
+    if (State->Stack.empty())
+      State.reset();
+
+    return *this;
+  }
 
-  const directory_entry &operator*() const;
-  const directory_entry *operator->() const;
+  const directory_entry &operator*() const { return *State->Stack.top(); };
+  const directory_entry *operator->() const { return &*State->Stack.top(); };
 
   // observers
-  /// Gets the current level. path is at level 0.
-  int level() const;
+  /// Gets the current level. Starting path is at level 0.
+  int level() const { return State->Level; }
+
   /// Returns true if no_push has been called for this directory_entry.
-  bool no_push_request() const;
+  bool no_push_request() const { return State->HasNoPushRequest; }
 
   // modifiers
   /// Goes up one level if Level > 0.
-  void pop();
+  void pop() {
+    assert(State && "Cannot pop and end itertor!");
+    assert(State->Level > 0 && "Cannot pop an iterator with level < 1");
+
+    static const directory_iterator end_itr;
+    error_code ec;
+    do {
+      if (ec)
+        report_fatal_error("Error incrementing directory iterator.");
+      State->Stack.pop();
+      --State->Level;
+    } while (!State->Stack.empty()
+             && State->Stack.top().increment(ec) == end_itr);
+
+    // Check if we are done. If so, create an end iterator.
+    if (State->Stack.empty())
+      State.reset();
+  }
+
   /// Does not go down into the current directory_entry.
-  void no_push();
+  void no_push() { State->HasNoPushRequest = true; }
 
+  bool operator==(const recursive_directory_iterator &RHS) const {
+    return State == RHS.State;
+  }
+
+  bool operator!=(const recursive_directory_iterator &RHS) const {
+    return !(*this == RHS);
+  }
   // Other members as required by
   // C++ Std, 24.1.1 Input iterators [input.iterators]
 };
diff --git a/lib/Support/Unix/PathV2.inc b/lib/Support/Unix/PathV2.inc
index bbbc344..7477b4f 100644
--- a/lib/Support/Unix/PathV2.inc
+++ b/lib/Support/Unix/PathV2.inc
@@ -439,7 +439,8 @@ rety_open_create:
   return success;
 }
 
-error_code directory_iterator_construct(directory_iterator &it, StringRef path){
+error_code detail::directory_iterator_construct(detail::DirIterState &it,
+                                                StringRef path){
   SmallString<128> path_null(path);
   DIR *directory = ::opendir(path_null.c_str());
   if (directory == 0)
@@ -452,7 +453,7 @@ error_code directory_iterator_construct(directory_iterator &it, StringRef path){
   return directory_iterator_increment(it);
 }
 
-error_code directory_iterator_destruct(directory_iterator& it) {
+error_code detail::directory_iterator_destruct(detail::DirIterState &it) {
   if (it.IterationHandle)
     ::closedir(reinterpret_cast<DIR *>(it.IterationHandle));
   it.IterationHandle = 0;
@@ -460,7 +461,7 @@ error_code directory_iterator_destruct(directory_iterator& it) {
   return success;
 }
 
-error_code directory_iterator_increment(directory_iterator& it) {
+error_code detail::directory_iterator_increment(detail::DirIterState &it) {
   errno = 0;
   dirent *cur_dir = ::readdir(reinterpret_cast<DIR *>(it.IterationHandle));
   if (cur_dir == 0 && errno != 0) {
diff --git a/lib/Support/Windows/PathV2.inc b/lib/Support/Windows/PathV2.inc
index bc597b2..3872512 100644
--- a/lib/Support/Windows/PathV2.inc
+++ b/lib/Support/Windows/PathV2.inc
@@ -535,7 +535,7 @@ error_code unique_file(const Twine &model, int &result_fd,
   if (makeAbsolute) {
     // Make model absolute by prepending a temp directory if it's not already.
     bool absolute = path::is_absolute(m);
-  
+
     if (!absolute) {
       SmallVector<wchar_t, 64> temp_dir;
       if (error_code ec = TempDir(temp_dir)) return ec;
@@ -691,7 +691,8 @@ error_code get_magic(const Twine &path, uint32_t len,
   return success;
 }
 
-error_code directory_iterator_construct(directory_iterator &it, StringRef path){
+error_code detail::directory_iterator_construct(detail::DirIterState &it,
+                                                StringRef path){
   SmallVector<wchar_t, 128> path_utf16;
 
   if (error_code ec = UTF8ToUTF16(path,
@@ -722,7 +723,7 @@ error_code directory_iterator_construct(directory_iterator &it, StringRef path){
       error_code ec = windows_error(::GetLastError());
       // Check for end.
       if (ec == windows_error::no_more_files)
-        return directory_iterator_destruct(it);
+        return detail::directory_iterator_destruct(it);
       return ec;
     } else
       FilenameLen = ::wcslen(FirstFind.cFileName);
@@ -742,7 +743,7 @@ error_code directory_iterator_construct(directory_iterator &it, StringRef path){
   return success;
 }
 
-error_code directory_iterator_destruct(directory_iterator& it) {
+error_code detail::directory_iterator_destruct(detail::DirIterState &it) {
   if (it.IterationHandle != 0)
     // Closes the handle if it's valid.
     ScopedFindHandle close(HANDLE(it.IterationHandle));
@@ -751,13 +752,13 @@ error_code directory_iterator_destruct(directory_iterator& it) {
   return success;
 }
 
-error_code directory_iterator_increment(directory_iterator& it) {
+error_code detail::directory_iterator_increment(detail::DirIterState &it) {
   WIN32_FIND_DATAW FindData;
   if (!::FindNextFileW(HANDLE(it.IterationHandle), &FindData)) {
     error_code ec = windows_error(::GetLastError());
     // Check for end.
     if (ec == windows_error::no_more_files)
-      return directory_iterator_destruct(it);
+      return detail::directory_iterator_destruct(it);
     return ec;
   }
 
diff --git a/unittests/Support/Path.cpp b/unittests/Support/Path.cpp
index 60d08bc..6d4dc4c 100644
--- a/unittests/Support/Path.cpp
+++ b/unittests/Support/Path.cpp
@@ -223,6 +223,57 @@ TEST_F(FileSystemTest, DirectoryIteration) {
   error_code ec;
   for (fs::directory_iterator i(".", ec), e; i != e; i.increment(ec))
     ASSERT_NO_ERROR(ec);
+
+  // Create a known hierarchy to recurse over.
+  bool existed;
+  ASSERT_NO_ERROR(fs::create_directories(Twine(TestDirectory)
+                  + "/recursive/a0/aa1", existed));
+  ASSERT_NO_ERROR(fs::create_directories(Twine(TestDirectory)
+                  + "/recursive/a0/ab1", existed));
+  ASSERT_NO_ERROR(fs::create_directories(Twine(TestDirectory)
+                  + "/recursive/dontlookhere/da1", existed));
+  ASSERT_NO_ERROR(fs::create_directories(Twine(TestDirectory)
+                  + "/recursive/z0/za1", existed));
+  ASSERT_NO_ERROR(fs::create_directories(Twine(TestDirectory)
+                  + "/recursive/pop/p1", existed));
+  typedef std::vector<std::string> v_t;
+  v_t visited;
+  for (fs::recursive_directory_iterator i(Twine(TestDirectory)
+         + "/recursive", ec), e; i != e; i.increment(ec)){
+    ASSERT_NO_ERROR(ec);
+    if (path::filename(i->path()) == "dontlookhere")
+      i.no_push();
+    if (path::filename(i->path()) == "p1")
+      i.pop();
+    visited.push_back(path::filename(i->path()));
+  }
+  v_t::const_iterator a0 = std::find(visited.begin(), visited.end(), "a0");
+  v_t::const_iterator aa1 = std::find(visited.begin(), visited.end(), "aa1");
+  v_t::const_iterator ab1 = std::find(visited.begin(), visited.end(), "ab1");
+  v_t::const_iterator dontlookhere = std::find(visited.begin(), visited.end(),
+                                               "dontlookhere");
+  v_t::const_iterator da1 = std::find(visited.begin(), visited.end(), "da1");
+  v_t::const_iterator z0 = std::find(visited.begin(), visited.end(), "z0");
+  v_t::const_iterator za1 = std::find(visited.begin(), visited.end(), "za1");
+  v_t::const_iterator pop = std::find(visited.begin(), visited.end(), "pop");
+  v_t::const_iterator p1 = std::find(visited.begin(), visited.end(), "p1");
+
+  // Make sure that each path was visited correctly.
+  ASSERT_NE(a0, visited.end());
+  ASSERT_NE(aa1, visited.end());
+  ASSERT_NE(ab1, visited.end());
+  ASSERT_NE(dontlookhere, visited.end());
+  ASSERT_EQ(da1, visited.end()); // Not visited.
+  ASSERT_NE(z0, visited.end());
+  ASSERT_NE(za1, visited.end());
+  ASSERT_NE(pop, visited.end());
+  ASSERT_EQ(p1, visited.end()); // Not visited.
+
+  // Make sure that parents were visited before children. No other ordering
+  // guarantees can be made across siblings.
+  ASSERT_LT(a0, aa1);
+  ASSERT_LT(a0, ab1);
+  ASSERT_LT(z0, za1);
 }
 
 TEST_F(FileSystemTest, Magic) {