[WIP] Provided file system from NACL.

ppapi/examples/filesystem_provider/memfilesystem.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "memfilesystem.h"
+
+#include <deque>
+
+namespace filesystem{
+
+Filesystem::Filesystem()
+    :currentInode_(1),
+    root_path("/") {
+  // Adding root directory
+  root_inode = GetNextInodeNumber();
+  InodeDirectory* root_directory = new InodeDirectory(this, root_inode);
+
+  // Add it to the list and increment ref count
+  if (root_directory){
+    PutInode(root_directory->inode_number(), root_directory);
+    AddLink(root_directory->inode_number());
+  }
+}
+
+Filesystem::~Filesystem() {
+  for (ListOfInodesIterator it(inodesList_.begin());
+      it != inodesList_.end(); it++)
+    delete it->second.second;
+
+  inodesList_.clear();
+}
+
+int Filesystem::GetMetadata(
+    const std::string& path,
+    Filesystem::NameInodePair &meta) {
+  std::string filePath = path.substr(path.find_last_of("/")+1);
+  Inode* inode = nullptr;
+
+  if(path.size()==0)//root
+    inode = GetInode(root_inode);
+  else
+    inode = GetInode( GetInodeFromPath(path) );
+
+  if (inode==nullptr)
+    return File_System_Error_NOT_FOUND;
+
+  meta.first = filePath;
+  meta.second = inode;
+
+  return File_System_Error_NONE;
+}
+
+
+int Filesystem::CreateDirectory(const std::string& path, bool recursive) {
+  if (path.size() == 0 ||
+      path[0] != '/')
+    return File_System_Error_NOT_FOUND;
+
+  std::deque<std::string> tree_entries;
+  size_t position = path.find_first_of("/");
+  std::string rest = path.substr( position + 1 );
+
+  // Break the path into components
+  // starting rigth after "/".
+  while (1) {
+       position = rest.find_first_of("/");
+       tree_entries.push_back(rest.substr(0, position) );
+       if (std::string::npos == position)
+         break;
+       rest = rest.substr(position + 1);
+  }
+
+  std::string current_dir = "";
+  unsigned long long workingInode = root_inode;
+  InodeDirectory*
+      current_inode = static_cast<InodeDirectory*>(GetInode(workingInode));
+
+  if (current_inode==nullptr||
+      current_inode->file_type()!=Inode::FILE_TYPE_DIR)
+    return File_System_Error_FAILED;
+
+  // At this point we have the root inode
+  // and we will traverse the path downwards and create
+  // if recursive is true intermediate directories
+  while (tree_entries.size() > 0) {
+    current_dir = tree_entries.front();
+    tree_entries.pop_front();
+    if (tree_entries.size() == 0) { // the new dir
+      InodeDirectory *new_dir =
+          new InodeDirectory(this, GetNextInodeNumber());
+      if (new_dir==nullptr)
+        return File_System_Error_FAILED;
+      // Add to the inode list
+      PutInode(new_dir->inode_number(), new_dir);
+      current_inode->AddEntry(current_dir, new_dir->inode_number());
+      return File_System_Error_NONE;
+    } else {
+      if ((workingInode =
+           current_inode->GetInodeFromName(current_dir))== Inode::NO_INODE) {
+        if (recursive == false) // all dirs must exist
+            return File_System_Error_NOT_FOUND;
+        else {
+          InodeDirectory *new_dir =
+              new InodeDirectory(this, GetNextInodeNumber());
+          if (new_dir==nullptr)
+            return File_System_Error_FAILED;
+          PutInode(new_dir->inode_number(), new_dir);
+          current_inode->AddEntry(current_dir, new_dir->inode_number());
+          // Hop into to the just created directory
+          current_inode = new_dir;
+          workingInode = new_dir->inode_number();
+        }
+       } else {
+         // hope into the directory
+         current_inode = static_cast<InodeDirectory*>( GetInode(workingInode) );
+         if(current_inode->file_type()!=Inode::FILE_TYPE_DIR)
+           return File_System_Error_NOT_FOUND;
+       }
+    }
+  }
+  return File_System_Error_FAILED;
+}
+
+int Filesystem::MoveEntry(
+    const std::string& sourcePath,
+    const std::string& targetPath) {
+  std::string sourceDir = sourcePath.substr(0, sourcePath.find_last_of("/"));
+  std::string targetDir = targetPath.substr(0, targetPath.find_last_of("/"));
+
+  std::string sourceFile = sourcePath.substr(sourcePath.find_last_of("/")+1);
+  std::string targetFile = targetPath.substr(targetPath.find_last_of("/") + 1);
+
+  if (sourceFile.size() == 0 ||
+      targetFile.size() == 0)
+    return File_System_Error_FAILED;
+
+  if (sourceDir.size() == 0)
+    sourceDir = "/";
+  if (targetDir.size() == 0)
+    targetDir = "/";
+
+  // Point to the parent dirs
+  InodeDirectory *srcInode =
+      static_cast<InodeDirectory*>(GetInode(GetInodeFromPath(sourceDir)));
+  InodeDirectory *dstInode =
+      static_cast<InodeDirectory*>(GetInode(GetInodeFromPath(targetDir)));
+
+  if (nullptr == srcInode ||
+      srcInode->file_type()!=Inode::FILE_TYPE_DIR||
+      nullptr == dstInode||
+      dstInode->file_type()!=Inode::FILE_TYPE_DIR)
+    return File_System_Error_NOT_FOUND;
+
+  unsigned long long toBeMoved = srcInode->GetInodeFromName(sourceFile);
+  if (toBeMoved == Inode::NO_INODE)
+    return File_System_Error_FAILED;
+
+  dstInode->AddEntry(targetFile, toBeMoved); // adds link
+  srcInode->DeleteEntry(sourceFile, toBeMoved); // removes link
+
+  return File_System_Error_NONE;
+}
+
+int Filesystem::CopyEntry(
+    const std::string& sourcePath,
+    const std::string& targetPath) {
+  std::string sourceDir = sourcePath.substr(0, sourcePath.find_last_of("/"));
+  std::string targetDir = targetPath.substr(0, targetPath.find_last_of("/"));
+
+  std::string sourceFile = sourcePath.substr(sourcePath.find_last_of("/") + 1);
+  std::string targetFile = targetPath.substr(targetPath.find_last_of("/") + 1);
+
+  if (sourceFile.size() == 0 ||
+      targetFile.size() == 0)
+    return File_System_Error_FAILED;
+
+  if (sourceDir.size() == 0)
+    sourceDir = "/";
+  if (targetDir.size() == 0)
+    targetDir = "/";
+
+  InodeDirectory *srcInode =
+      static_cast<InodeDirectory*>(GetInode(GetInodeFromPath(sourceDir)));
+  InodeDirectory *dstInode =
+      static_cast<InodeDirectory*>(GetInode(GetInodeFromPath(targetDir)));
+
+  if (nullptr == srcInode ||
+      srcInode->file_type()!=Inode::FILE_TYPE_DIR||
+      nullptr == dstInode||
+      dstInode->file_type()!=Inode::FILE_TYPE_DIR)
+    return File_System_Error_NOT_FOUND;
+
+  unsigned long long toBeCopied = srcInode->GetInodeFromName(sourceFile);
+  if (toBeCopied == Inode::NO_INODE)
+    return File_System_Error_FAILED;
+
+  Inode* old_inode =  GetInode(toBeCopied);
+
+  if (nullptr == old_inode)
+    return File_System_Error_NOT_FOUND;
+
+  Inode* new_inode = nullptr;
+  if (old_inode->file_type() == Inode::FILE_TYPE_FILE) {
+    InodeFile *temp = static_cast<InodeFile*>(old_inode);
+    new_inode = new InodeFile(*temp);
+    if (nullptr == new_inode)
+      return File_System_Error_FAILED;
+  }
+  else if (old_inode->file_type() == Inode::FILE_TYPE_DIR) {
+    InodeDirectory *temp = static_cast<InodeDirectory*>(old_inode);
+    new_inode = new InodeDirectory(*temp);
+    if (nullptr == new_inode)
+      return File_System_Error_FAILED;
+  }
+
+  new_inode->set_inode_number(GetNextInodeNumber());
+  PutInode(new_inode->inode_number(), new_inode);
+  new_inode->set_inode_modified();
+
+  dstInode->AddEntry(targetFile, new_inode->inode_number());
+  return File_System_Error_NONE;
+}
+
+
+int Filesystem::DeleteEntry(const std::string& path, bool recursive) {
+  unsigned long long workingInode = GetInodeFromPath(path);
+  Inode* current_inode = GetInode(workingInode);
+
+  if (nullptr == current_inode)
+    return File_System_Error_NOT_FOUND;
+
+  if (current_inode->file_type() == Inode::FILE_TYPE_DIR &&
+      !recursive)
+    return File_System_Error_NOT_FOUND;
+
+  std::string dir = path.substr(0, path.find_last_of("/"));
+  if (dir.size() == 0)
+    dir = "/";
+
+  InodeDirectory* parent_inode =
+      static_cast<InodeDirectory*>(GetInode(GetInodeFromPath(dir)));
+  if (nullptr == parent_inode||
+      parent_inode->file_type()!=Inode::FILE_TYPE_DIR)
+    return File_System_Error_NOT_FOUND;
+  parent_inode->DeleteEntry(
+    path.substr(path.find_last_of("/")+1), workingInode);
+
+  return File_System_Error_NONE;
+}
+
+int Filesystem::ReadDirectory (
+  const std::string& path,
+  std::vector<NameInodePair>& metas){
+
+  InodeDirectory* inode_directory =
+    static_cast<InodeDirectory*>(GetInode(GetInodeFromPath(path)));
+
+  if (nullptr==inode_directory||
+      inode_directory->file_type()!=Inode::FILE_TYPE_DIR)
+    return File_System_Error_FAILED;
+  std::vector< InodeDirectory::EntryPair > listOfEntries;
+  inode_directory->GetAllInodes(listOfEntries);
+  Inode* inode = nullptr;
+  for (std::vector< InodeDirectory::EntryPair >::iterator
+       it(listOfEntries.begin());
+       it != listOfEntries.end(); it++) {
+    inode = GetInode(it->second);
+    if (nullptr != inode)
+      metas.push_back(NameInodePair(it->first, inode));
+  }
+  return File_System_Error_NONE;
+}
+
+int Filesystem::CreateFile(const std::string& filePath) {
+  std::string targetDir = filePath.substr(0, filePath.find_last_of("/"));
+  std::string filename = filePath.substr(filePath.find_last_of("/") + 1);
+
+  if (targetDir.size() == 0)
+    targetDir = "/";
+  if (filename.size()==0)
+    return File_System_Error_FAILED;
+  InodeDirectory* inode_directory =
+    static_cast<InodeDirectory*>(GetInode(GetInodeFromPath(targetDir)));
+  if (nullptr == inode_directory||
+      inode_directory->file_type()!=Inode::FILE_TYPE_DIR)
+    return File_System_Error_FAILED;
+
+  InodeFile* inode_file = new InodeFile(GetNextInodeNumber());
+  if (nullptr == inode_file)
+    return File_System_Error_FAILED;
+
+  PutInode(inode_file->inode_number(), inode_file);
+  inode_directory->AddEntry(filename, inode_file->inode_number());
+  return File_System_Error_NONE;
+}
+
+int Filesystem::Truncate(const std::string &filePath, size_t length) {
+  InodeFile *inode_file =
+      static_cast<InodeFile*>( GetInode( GetInodeFromPath(filePath) ) );
+  if (inode_file==nullptr ||
+      inode_file->file_type() != Inode::FILE_TYPE_FILE)
+    return File_System_Error_NOT_FOUND;
+
+  inode_file->Truncate(length);
+  return File_System_Error_NONE;
+}
+
+int Filesystem::WriteToFile(
+    const std::string &filePath,
+    size_t offset,
+    size_t dataSize,
+    const char *data) {
+  InodeFile *inode_file =
+      static_cast<InodeFile*>( GetInode( GetInodeFromPath(filePath) ) );
+  if(inode_file==nullptr||
+     inode_file->file_type()!=Inode::FILE_TYPE_FILE)
+    return File_System_Error_NOT_FOUND;
+
+  if( inode_file->Write(data, offset, dataSize) )
+    return File_System_Error_NONE;
+  return File_System_Error_FAILED;
+}
+
+int Filesystem::ReadFromFile(const std::string &filePath,
+    size_t offset,
+    size_t* inOutLength,
+    const char** outData) {
+  InodeFile *inode_file =
+      static_cast<InodeFile*>( GetInode( GetInodeFromPath(filePath) ) );
+  if (inode_file==nullptr||
+      inode_file->file_type()!=Inode::FILE_TYPE_FILE)
+    return File_System_Error_NOT_FOUND;
+
+  if (inode_file->Read(offset, inOutLength, outData ))
+    return File_System_Error_NONE;
+  return File_System_Error_FAILED;
+}
+
+void Filesystem::AddLink(unsigned long long inode) {
+  ListOfInodesIterator it(inodesList_.find(inode));
+  if (it != inodesList_.end()) {
+    it->second.first++;
+    // If directory add a reference for each entry it contains
+    if (it->second.second->file_type() == Inode::FILE_TYPE_DIR) {
+      InodeDirectory* inode_directory =
+          static_cast<InodeDirectory*>(it->second.second);
+      if (nullptr == inode_directory)
+        return;
+      std::vector<InodeDirectory::EntryPair> entries;
+      inode_directory->GetAllInodes(entries);
+      for (std::vector<InodeDirectory::EntryPair>::iterator
+           entry = entries.begin();
+           entry != entries.end(); ++entry) {
+        AddLink(entry->second);
+      }
+    }
+  }
+}
+void Filesystem::RemoveLink(unsigned long long inode_number) {
+  ListOfInodesIterator it(inodesList_.find(inode_number));
+  if (it != inodesList_.end()) {
+    Inode* inode = it->second.second;
+    if (nullptr == inode)
+      return;
+    if (inode->file_type() == Inode::FILE_TYPE_DIR) {
+      InodeDirectory* inode_directory =
+        static_cast<InodeDirectory*>(inode);
+      if (nullptr == inode_directory)
+        return;
+      // Get all inodes and remove their reference
+      std::vector<InodeDirectory::EntryPair> entries;
+      inode_directory->GetAllInodes(entries);
+      for (std::vector<InodeDirectory::EntryPair>::iterator
+           entry = entries.begin();
+           entry != entries.end(); entry++) {
+        RemoveLink(entry->second);
+      }
+    }
+    // If current reference is down to 0
+    // then remove it
+    if (--it->second.first==0) {
+      delete inode;
+      inodesList_.erase(it);
+    }
+  }
+}
+
+Inode* Filesystem::GetInode(unsigned long long inode) {
+  ListOfInodesIterator it = inodesList_.find(inode);
+  if (it == inodesList_.end())
+    return nullptr;
+  return it->second.second;
+}
+
+void Filesystem::PutInode(unsigned long long inode_number, Inode* inode) {
+  inodesList_.insert(std::pair<unsigned long long,InodePair >(
+      inode_number, InodePair( 0, inode) ) );
+}
+void Filesystem::RemoveInode(unsigned long long inode) {
+  ListOfInodesIterator it = inodesList_.find(inode);
+  inodesList_.erase(it);
+}
+
+unsigned long long Filesystem::GetInodeFromPath(const std::string& path){
+  if (path.size() == 0 ||
+      path[0] != '/')
+    return File_System_Error_NOT_FOUND;
+
+  std::deque<std::string> tree_entries;
+  std::string::size_type position = 0;
+  std::string rest = path.substr(1);
+  std::string temp;
+
+  while (1) {
+    position = rest.find_first_of("/");
+    temp = rest.substr(0, position);
+    if (temp.size()!=0)
+      tree_entries.push_back(temp);
+    if (std::string::npos == position)
+      break;
+    rest = rest.substr(position + 1);
+  }
+
+  std::string current_dir = "";
+  unsigned long long workingInode = root_inode;
+  InodeDirectory* current_inode =
+      static_cast<InodeDirectory*>(GetInode(workingInode));
+  if (current_inode==nullptr||
+      current_inode->file_type()!=Inode::FILE_TYPE_DIR)
+    return Inode::NO_INODE;
+  while ( tree_entries.size() > 0) {
+    current_dir = tree_entries.front();
+    tree_entries.pop_front();
+
+    workingInode = current_inode->GetInodeFromName(current_dir);
+    if (workingInode == Inode::NO_INODE)
+      return File_System_Error_NOT_FOUND;
+    if (tree_entries.size() > 0) {
+      current_inode =
+          static_cast<InodeDirectory*>(GetInode(workingInode));
+      if (current_inode==nullptr||
+          current_inode->file_type()!=Inode::FILE_TYPE_DIR)
+        return Inode::NO_INODE;
+    }
+  }
+  return workingInode;
+}
+
+unsigned long long  Filesystem::GetNextInodeNumber(){
+  if (++currentInode_ == Inode::NO_INODE)
+    return ++currentInode_;
+  return currentInode_;
+}
+
+
+}// namespace filesystem