mark as deleted and zero content on deletion instead of shifting everything

src/common.h

@@ -2,7 +2,6 @@
 
 #include <cstdint>
 #include <iostream>
-#include <string>
 
 #define ASSERT(cond)                                                           \
   do {                                                                         \
@@ -25,11 +24,3 @@ static_assert(sizeof(float) * 8 == 32);
 using f32 = float;
 static_assert(sizeof(double) * 8 == 64);
 using f64 = double;
-
-template <typename T> constexpr char *to_char_ptr(T *ptr) noexcept {
-  return reinterpret_cast<char *>(ptr);
-}
-
-template <typename T> constexpr const char *to_char_ptr(const T *ptr) noexcept {
-  return reinterpret_cast<const char *>(ptr);
-}

src/mainwindow.cc

@@ -230,13 +230,15 @@ void MainWindow::file_context_menu(const QPoint &pos) {
 
   QMenu menu(this);
 
-  QAction *preview_action = menu.addAction(
+  QAction *preview_action =
-      style()->standardIcon(QStyle::SP_FileDialogContentsView), "Preview");
+      menu.addAction(style()->standardIcon(QStyle::SP_FileDialogContentsView),
+                     "Preview as text");
   connect(preview_action, &QAction::triggered, this,
           [this, item]() { preview_file(item->text(0).toStdString()); });
 
-  QAction *edit_action = menu.addAction(
+  QAction *edit_action =
-      style()->standardIcon(QStyle::SP_FileDialogDetailedView), "Edit");
+      menu.addAction(style()->standardIcon(QStyle::SP_FileDialogDetailedView),
+                     "Edit in external app");
   connect(edit_action, &QAction::triggered, this,
           [this, item]() { edit_file(item->text(0).toStdString()); });
 

src/vault.cc

@@ -2,7 +2,18 @@
 #include "common.h"
 #include "crypto.h"
 #include <botan/auto_rng.h>
-#include <filesystem>
+
+namespace {
+
+template <typename T> constexpr char *to_char_ptr(T *ptr) noexcept {
+  return reinterpret_cast<char *>(ptr);
+}
+
+template <typename T> constexpr const char *to_char_ptr(const T *ptr) noexcept {
+  return reinterpret_cast<const char *>(ptr);
+}
+
+} // namespace
 
 Vault::Vault(std::string path, const std::string &password)
     : m_path(std::move(path)) {
@@ -57,7 +68,9 @@ std::vector<FileHeader> Vault::read_file_headers() {
   while (true) {
     auto header = read_file_header();
     if (header) {
-      headers.push_back(header.value());
+      if (!header->deleted) {
+        headers.push_back(header.value());
+      }
       m_file.seekg(static_cast<i64>(header->content_ciphertext_size),
                    std::ios::cur);
     } else {
@@ -78,7 +91,7 @@ std::optional<std::string> Vault::read_file(const std::string &filename) {
       break;
     }
 
-    if (header->name == filename) {
+    if (!header->deleted && header->name == filename) {
       Botan::secure_vector<u8> ciphertext;
       ciphertext.resize(header->content_ciphertext_size);
       if (!m_file.read(to_char_ptr(ciphertext.data()),
@@ -110,6 +123,7 @@ void Vault::create_file(const std::string &filename,
   auto ciphertext = Crypto::encrypt(m_key, content_sv);
   u64 ciphertext_size = ciphertext.size();
 
+  ASSERT(m_file.write("\0", 1)); // deleted flag
   ASSERT(m_file.write(to_char_ptr(&filename_ciphertext_size), sizeof(u64)));
   ASSERT(m_file.write(to_char_ptr(filename_ciphertext.data()),
                       static_cast<i64>(filename_ciphertext_size)));
@@ -123,9 +137,6 @@ void Vault::delete_file(const std::string &filename) {
   m_file.clear();
   m_file.seekg(AFTER_HEADER_OFFSET, std::ios::beg);
 
-  i64 entry_start = -1;
-  u64 entry_total_size = 0;
-
   while (true) {
     i64 current_pos = m_file.tellg();
 
@@ -134,49 +145,21 @@ void Vault::delete_file(const std::string &filename) {
       break;
     }
 
-    if (header->name == filename) {
+    if (!header->deleted && header->name == filename) {
-      entry_start = current_pos;
+      // zero the ciphertext and mark as deleted
-      entry_total_size = sizeof(u64) + header->name_ciphertext_size +
+      m_file.seekp(m_file.tellg());
-                         sizeof(u64) + header->content_ciphertext_size;
+      for (size_t i = 0; i < header->content_ciphertext_size; i++) {
-      m_file.seekg(static_cast<i64>(header->content_ciphertext_size),
+        m_file.write(to_char_ptr("\0"), 1);
-                   std::ios::cur);
+      }
+
+      m_file.seekp(current_pos, std::ios::beg);
+      m_file.write(to_char_ptr("\1"), 1);
       break;
     }
 
     m_file.seekg(static_cast<i64>(header->content_ciphertext_size),
                  std::ios::cur);
   }
-
-  if (entry_start != -1) {
-    i64 entry_end = entry_start + static_cast<i64>(entry_total_size);
-
-    i64 read_pos = entry_end;
-    i64 write_pos = entry_start;
-    std::array<u8, 65536> buffer{};
-    while (true) {
-      m_file.clear();
-      m_file.seekg(read_pos);
-      m_file.read(to_char_ptr(buffer.data()), buffer.size());
-      auto bytes = m_file.gcount();
-      if (bytes == 0) {
-        break;
-      }
-
-      m_file.seekp(write_pos);
-      ASSERT(m_file.write(to_char_ptr(buffer.data()), bytes));
-
-      read_pos += bytes;
-      write_pos += bytes;
-    }
-
-    m_file.flush();
-    m_file.close();
-
-    std::filesystem::resize_file(m_path, write_pos);
-
-    m_file.open(m_path, std::ios::in | std::ios::out | std::ios::binary);
-    ASSERT(m_file.good());
-  }
 }
 
 void Vault::update_file(const std::string &filename,
@@ -188,6 +171,10 @@ void Vault::update_file(const std::string &filename,
 std::optional<FileHeader> Vault::read_file_header() {
   FileHeader header{};
 
+  if (!m_file.read(to_char_ptr(&header.deleted), 1)) {
+    return std::nullopt;
+  }
+
   if (!m_file.read(to_char_ptr(&header.name_ciphertext_size), sizeof(u64))) {
     return std::nullopt;
   }
@@ -201,10 +188,14 @@ std::optional<FileHeader> Vault::read_file_header() {
     return std::nullopt;
   }
 
-  auto name = Crypto::decrypt(m_key, name_ciphertext);
+  if (!header.deleted) {
-  header.name = std::string(name.begin(), name.end());
+    auto name = Crypto::decrypt(m_key, name_ciphertext);
+    header.name = std::string(name.begin(), name.end());
+  }
+
   if (!m_file.read(to_char_ptr(&header.content_ciphertext_size), sizeof(u64))) {
     return std::nullopt;
   }
+
   return header;
 }

src/vault.h

@@ -10,6 +10,7 @@ constexpr u64 AFTER_HEADER_OFFSET = 68;
 
 // !!! REMEMBER TO UPDATE entry_total_size IN Vault::delete_file
 struct FileHeader {
+  bool deleted;
   u64 name_ciphertext_size;
   std::string name;
   u64 content_ciphertext_size;