xnoe-os/src/kernel/filesystem/vfs.cpp

#include "vfs.h"

void VFS::addEntry(Path p, ReadWriter*(*constructor)(Path)) {
  PathElement* currentPathElement = p.start;

  VFSTreeNode* currentNode = this->root;

  if (!currentPathElement)
    return currentNode;

nextPE:
  while (currentPathElement) {
    xnoe::linkedlistelem<VFSTreeNode*>* currentChild = currentNode->children.start;
    while (currentChild) {
      if (currentChild->elem->self == currentPathElement->elem) {
        currentNode = currentChild->elem;
        currentPathElement = currentPathElement->next;
        goto nextPE;
      }
      currentChild = currentChild->next;
    }
    if (currentPathElement = p.end) {
      currentNode->children.append(new VFSTreeNode{currentPathElement->elem, xnoe::linkedlist<VFSTreeNode*>(), constructor, false});
    } else {
      if (currentPathElement->elem == PathEntry{1, "*"})
        currentNode->children.append(new VFSTreeNode{currentPathElement->elem, xnoe::linkedlist<VFSTreeNode*>(), 0, true});
      else
        currentNode->children.append(new VFSTreeNode{currentPathElement->elem, xnoe::linkedlist<VFSTreeNode*>(), 0, false});
    }
    currentNode = currentNode->children.end->elem;
    currentPathElement = currentPathElement->next;
  }

  return currentNode;
}

Constructor VFS::getEntry(Path p) {
  PathElement* currentPathElement = p.start;
  VFSTreeNode* currentNode = this->root;

  if (!currentPathElement)
    return 0;

nextPE:
  while (currentPathElement) {
    xnoe::linkedlistelem<VFSTreeNode*>* currentChild = currentNode->children.start;
    while (currentChild) {
      if (currentChild->elem->self == currentPathElement->elem || currentChild->elem->wildcard) {
        currentNode = currentChild->elem;
        currentPathElement = currentPathElement->next;
        goto nextPE;
      }
      currentChild = currentChild->next;
    }
    return 0;
  }
  if (currentNode->children.length == 0)
    return currentNode->constructor;
  return 0;
}

VFSTreeNode* VFS::getNode(Path p) {
  PathElement* currentPathElement = p.start;
  VFSTreeNode* currentNode = this->root;

nextPE:
  while (currentPathElement) {
    xnoe::linkedlistelem<VFSTreeNode*>* currentChild = currentNode->children.start;
    while (currentChild) {
      if (currentChild->elem->self == currentPathElement->elem || currentChild->elem->wildcard) {
        currentNode = currentChild->elem;
        currentPathElement = currentPathElement->next;
        goto nextPE;
      }
      currentChild = currentChild->next;
    }
    return 0;
  }
  return currentNode;
}

bool VFS::exists(Path p) {
  return getEntry(p);
}

ReadWriter* VFS::open(Path p) {
  Constructor c = getEntry(p);
  return c(p);
}

uint32_t VFS::getDentsSize(Path p) {
  VFSTreeNode* node = getNode(p);
  if (!node)
    return 0;
  
  uint32_t total = sizeof(FSDirectoryListing);
  xnoe::linkedlistelem<VFSTreeNode*>* currentNode = node->children.start;
  while (currentNode) {
    total += sizeof(FSDirectoryEntry);
    total += currentNode->elem->self.length;
    currentNode = currentNode->next;
  }
  return total;
}

void VFS::getDents(Path p, FSDirectoryListing* buffer) {
  VFSTreeNode* node = getNode(p);
  if (!node)
    return;
  
  uint32_t total = sizeof(FSDirectoryListing);
  xnoe::linkedlistelem<VFSTreeNode*>* currentNode = node->children.start;
  buffer->count = 0;
  while (currentNode) {
    buffer->count++;
    currentNode = currentNode->next;
  }

  uint8_t* strings = (uint8_t*)(buffer) + sizeof(FSDirectoryListing) + sizeof(FSDirectoryEntry) * buffer->count;
  currentNode = node->children.start;
  uint32_t index = 0;
  while (currentNode) {
    memcpy(strings, currentNode->elem->self.path, currentNode->elem->self.length);
    buffer->entries[index++] = FSDirectoryEntry{
      PathEntry{currentNode->elem->self.length, strings},
      File,
      0
    };
    strings += currentNode->elem->self.length;
    buffer->stringsLength += currentNode->elem->self.length;
    currentNode = currentNode->next;
  }
}