--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/FileStorage.cpp	Thu Jul 19 14:32:22 2012 +0200
@@ -0,0 +1,274 @@
+/**
+ * Palantir - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012 Medical Physics Department, CHU of Liege,
+ * Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "FileStorage.h"
+
+// http://stackoverflow.com/questions/1576272/storing-large-number-of-files-in-file-system
+// http://stackoverflow.com/questions/446358/storing-a-large-number-of-images
+
+#include "PalantirException.h"
+#include "Toolbox.h"
+#include "Uuid.h"
+
+#include <boost/filesystem/fstream.hpp>
+
+namespace Palantir
+{
+  boost::filesystem::path FileStorage::GetPath(const std::string& uuid) const
+  {
+    namespace fs = boost::filesystem;
+
+    if (!Toolbox::IsUuid(uuid))
+    {
+      throw PalantirException(ErrorCode_ParameterOutOfRange);
+    }
+
+    fs::path path = root_;
+
+    path /= std::string(&uuid[0], &uuid[2]);
+    path /= std::string(&uuid[2], &uuid[4]);
+    path /= uuid;
+    path.make_preferred();
+
+    return path;
+  }
+
+  FileStorage::FileStorage(std::string root)
+  {
+    namespace fs = boost::filesystem;
+
+    root_ = fs::absolute(root);
+
+    if (fs::exists(root))
+    {
+      if (!fs::is_directory(root))
+      {
+        throw PalantirException("The file storage root directory is a file");
+      }
+    }
+    else
+    {
+      if (!fs::create_directories(root))
+      {
+        throw PalantirException("Unable to create the file storage root directory");
+      }
+    }
+  }
+
+  std::string FileStorage::CreateFileWithoutCompression(const void* content, size_t size)
+  {
+    std::string uuid;
+    boost::filesystem::path path;
+    
+    for (;;)
+    {
+      uuid = Toolbox::GenerateUuid();
+      path = GetPath(uuid);
+
+      if (!boost::filesystem::exists(path))
+      {
+        // OK, this is indeed a new file
+        break;
+      }
+
+      // Extremely improbable case: This Uuid has already been created
+      // in the past. Try again.
+    }
+
+    if (boost::filesystem::exists(path.parent_path()))
+    {
+      if (!boost::filesystem::is_directory(path.parent_path()))
+      {
+        throw PalantirException("The subdirectory to be created is already occupied by a regular file");        
+      }
+    }
+    else
+    {
+      if (!boost::filesystem::create_directories(path.parent_path()))
+      {
+        throw PalantirException("Unable to create a subdirectory in the file storage");        
+      }
+    }
+
+    boost::filesystem::ofstream f;
+    f.open(path, std::ofstream::out | std::ios::binary);
+    if (!f.good())
+    {
+      throw PalantirException("Unable to create a new file in the file storage");
+    }
+
+    if (size != 0)
+    {
+      f.write(static_cast<const char*>(content), size);
+      if (!f.good())
+      {
+        f.close();
+        throw PalantirException("Unable to write to the new file in the file storage");
+      }
+    }
+
+    f.close();
+
+    return uuid;
+  } 
+
+
+  std::string FileStorage::Create(const void* content, size_t size)
+  {
+    if (!HasBufferCompressor() || size == 0)
+    {
+      return CreateFileWithoutCompression(content, size);
+    }
+    else
+    {
+      std::string compressed;
+      compressor_->Compress(compressed, content, size);
+      assert(compressed.size() > 0);
+      return CreateFileWithoutCompression(&compressed[0], compressed.size());
+    }
+  }
+
+
+  std::string FileStorage::Create(const std::vector<uint8_t>& content)
+  {
+    if (content.size() == 0)
+      return Create(NULL, 0);
+    else
+      return Create(&content[0], content.size());
+  }
+
+  std::string FileStorage::Create(const std::string& content)
+  {
+    if (content.size() == 0)
+      return Create(NULL, 0);
+    else
+      return Create(&content[0], content.size());
+  }
+
+  void FileStorage::ReadFile(std::string& content,
+                             const std::string& uuid) const
+  {
+    content.clear();
+
+    if (HasBufferCompressor())
+    {
+      std::string compressed;
+      Toolbox::ReadFile(compressed, GetPath(uuid).string());
+
+      if (compressed.size() != 0)
+      {
+        compressor_->Uncompress(content, compressed);
+      }
+    }
+    else
+    {
+      Toolbox::ReadFile(content, GetPath(uuid).string());
+    }
+  }
+
+
+  uintmax_t FileStorage::GetCompressedSize(const std::string& uuid) const
+  {
+    boost::filesystem::path path = GetPath(uuid);
+    return boost::filesystem::file_size(path);
+  }
+
+
+
+  void FileStorage::ListAllFiles(std::set<std::string>& result) const
+  {
+    namespace fs = boost::filesystem;
+
+    result.clear();
+
+    if (fs::exists(root_) && fs::is_directory(root_))
+    {
+      for (fs::recursive_directory_iterator current(root_), end; current != end ; ++current)
+      {
+        if (fs::is_regular_file(current->status()))
+        {
+          try
+          {
+            fs::path d = current->path();
+            std::string uuid = d.filename().string();
+            if (Toolbox::IsUuid(uuid))
+            {
+              fs::path p0 = d.parent_path().parent_path().parent_path();
+              std::string p1 = d.parent_path().parent_path().filename().string();
+              std::string p2 = d.parent_path().filename().string();
+              if (p1.length() == 2 &&
+                  p2.length() == 2 &&
+                  p1 == uuid.substr(0, 2) &&
+                  p2 == uuid.substr(2, 2) &&
+                  p0 == root_)
+              {
+                result.insert(uuid);
+              }
+            }
+          }
+          catch (fs::filesystem_error)
+          {
+          }
+        }
+      }
+    }
+  }
+
+
+  void FileStorage::Clear()
+  {
+    namespace fs = boost::filesystem;
+    typedef std::set<std::string> List;
+
+    List result;
+    ListAllFiles(result);
+
+    for (List::const_iterator it = result.begin(); it != result.end(); it++)
+    {
+      Remove(*it);
+    }
+  }
+
+
+  void FileStorage::Remove(const std::string& uuid)
+  {
+    namespace fs = boost::filesystem;
+
+    fs::path p = GetPath(uuid);
+    fs::remove(p);
+
+    // Remove the two parent directories, ignoring the error code if
+    // these directories are not empty
+    boost::system::error_code err;
+    fs::remove(p.parent_path(), err);
+    fs::remove(p.parent_path().parent_path(), err);
+  }
+
+
+  uintmax_t FileStorage::GetCapacity() const
+  {
+    return boost::filesystem::space(root_).capacity;
+  }
+
+  uintmax_t FileStorage::GetAvailableSpace() const
+  {
+    return boost::filesystem::space(root_).available;
+  }
+}