Disk cache: Add a tool to upgrade a set of cache files from one version to...

net/tools/dump_cache/dump_files.cc

+// Copyright (c) 2008 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.
+
+// Performs basic inspection of the disk cache files with minimal disruption
+// to the actual files (they still may change if an error is detected on the
+// files).
+
+#include <stdio.h>
+#include <string>
+
+#include "base/file_util.h"
+#include "base/message_loop.h"
+#include "net/base/file_stream.h"
+#include "net/disk_cache/block_files.h"
+#include "net/disk_cache/disk_format.h"
+#include "net/disk_cache/mapped_file.h"
+#include "net/disk_cache/storage_block.h"
+
+namespace {
+
+const wchar_t kIndexName[] = L"index";
+const wchar_t kDataPrefix[] = L"data_";
+
+// Reads the |header_size| bytes from the beginning of file |name|.
+bool ReadHeader(const std::wstring name, char* header, int header_size) {
+  net::FileStream file;
+  file.Open(name, base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ);
+  if (!file.IsOpen()) {
+    printf("Unable to open file %ls\n", name.c_str());
+    return false;
+  }
+
+  int read = file.Read(header, header_size, NULL);
+  if (read != header_size) {
+    printf("Unable to read file %ls\n", name.c_str());
+    return false;
+  }
+  return true;
+}
+
+int GetMajorVersionFromFile(const std::wstring name) {
+  disk_cache::IndexHeader header;
+  if (!ReadHeader(name, reinterpret_cast<char*>(&header), sizeof(header)))
+    return 0;
+
+  return header.version >> 16;
+}
+
+// Dumps the contents of the Index-file header.
+void DumpIndexHeader(const std::wstring name) {
+  disk_cache::IndexHeader header;
+  if (!ReadHeader(name, reinterpret_cast<char*>(&header), sizeof(header)))
+    return;
+
+  printf("Index file:\n");
+  printf("magic: %x\n", header.magic);
+  printf("version: %d.%d\n", header.version >> 16, header.version & 0xffff);
+  printf("entries: %d\n", header.num_entries);
+  printf("total bytes: %d\n", header.num_bytes);
+  printf("last file number: %d\n", header.last_file);
+  printf("current id: %d\n", header.this_id);
+  printf("table length: %d\n", header.table_len);
+  printf("-------------------------\n\n");
+}
+
+// Dumps the contents of a block-file header.
+void DumpBlockHeader(const std::wstring name) {
+  disk_cache::BlockFileHeader header;
+  if (!ReadHeader(name, reinterpret_cast<char*>(&header), sizeof(header)))
+    return;
+
+  std::wstring file_name = file_util::GetFilenameFromPath(name);
+
+  printf("Block file: %ls\n", file_name.c_str());
+  printf("magic: %x\n", header.magic);
+  printf("version: %d.%d\n", header.version >> 16, header.version & 0xffff);
+  printf("file id: %d\n", header.this_file);
+  printf("next file id: %d\n", header.next_file);
+  printf("entry size: %d\n", header.entry_size);
+  printf("current entries: %d\n", header.num_entries);
+  printf("max entries: %d\n", header.max_entries);
+  printf("updating: %d\n", header.updating);
+  printf("empty sz 1: %d\n", header.empty[0]);
+  printf("empty sz 2: %d\n", header.empty[1]);
+  printf("empty sz 3: %d\n", header.empty[2]);
+  printf("empty sz 4: %d\n", header.empty[3]);
+  printf("user 0: 0x%x\n", header.user[0]);
+  printf("user 1: 0x%x\n", header.user[1]);
+  printf("user 2: 0x%x\n", header.user[2]);
+  printf("user 3: 0x%x\n", header.user[3]);
+  printf("-------------------------\n\n");
+}
+
+// Simple class that interacts with the set of cache files.
+class CacheDumper {
+public:
+  explicit CacheDumper(const std::wstring path)
+      : path_(path), block_files_(path), index_(NULL) {}
+
+  bool Init();
+
+  // Reads an entry from disk. Return false when all entries have been already
+  // returned.
+  bool GetEntry(disk_cache::EntryStore* entry);
+
+  // Loads a specific block from the block files.
+  bool LoadEntry(disk_cache::CacheAddr addr, disk_cache::EntryStore* entry);
+  bool LoadRankings(disk_cache::CacheAddr addr,
+                    disk_cache::RankingsNode* rankings);
+
+private:
+  std::wstring path_;
+  disk_cache::BlockFiles block_files_;
+  scoped_refptr<disk_cache::MappedFile> index_file_;
+  disk_cache::Index* index_;
+  int current_hash_;
+  disk_cache::CacheAddr next_addr_;
+  DISALLOW_COPY_AND_ASSIGN(CacheDumper);
+};
+
+bool CacheDumper::Init() {
+  if (!block_files_.Init(false)) {
+    printf("Unable to init block files\n");
+    return false;
+  }
+
+  std::wstring index_name(path_);
+  file_util::AppendToPath(&index_name, kIndexName);
+  index_file_ = new disk_cache::MappedFile;
+  index_ =
+      reinterpret_cast<disk_cache::Index*>(index_file_->Init(index_name, 0));
+  if (!index_) {
+    printf("Unable to map index\n");
+    return false;
+  }
+
+  current_hash_ = 0;
+  next_addr_ = 0;
+  return true;
+}
+
+bool CacheDumper::GetEntry(disk_cache::EntryStore* entry) {
+  if (next_addr_) {
+    if (LoadEntry(next_addr_, entry)) {
+      next_addr_ = entry->next;
+      if (!next_addr_)
+        current_hash_++;
+      return true;
+    } else {
+      printf("Unable to load entry at address 0x%x\n", next_addr_);
+      next_addr_ = 0;
+      current_hash_++;
+    }
+  }
+
+  for (int i = current_hash_; i < index_->header.table_len; i++) {
+    // Yes, we'll crash if the table is shorter than expected, but only after
+    // dumping every entry that we can find.
+    if (index_->table[i]) {
+      current_hash_ = i;
+      if (LoadEntry(index_->table[i], entry)) {
+        next_addr_ = entry->next;
+        if (!next_addr_)
+          current_hash_++;
+        return true;
+      } else {
+        printf("Unable to load entry at address 0x%x\n", index_->table[i]);
+      }
+    }
+  }
+  return false;
+}
+
+bool CacheDumper::LoadEntry(disk_cache::CacheAddr addr,
+                            disk_cache::EntryStore* entry) {
+  disk_cache::Addr address(addr);
+  disk_cache::MappedFile* file = block_files_.GetFile(address);
+  if (!file)
+    return false;
+
+  disk_cache::CacheEntryBlock entry_block(file, address);
+  if (!entry_block.Load())
+    return false;
+
+  memcpy(entry, entry_block.Data(), sizeof(*entry));
+  printf("Entry at 0x%x\n", addr);
+  return true;
+}
+
+bool CacheDumper::LoadRankings(disk_cache::CacheAddr addr,
+                               disk_cache::RankingsNode* rankings) {
+  disk_cache::Addr address(addr);
+  disk_cache::MappedFile* file = block_files_.GetFile(address);
+  if (!file)
+    return false;
+
+  disk_cache::CacheRankingsBlock rank_block(file, address);
+  if (!rank_block.Load())
+    return false;
+
+  memcpy(rankings, rank_block.Data(), sizeof(*rankings));
+  printf("Rankings at 0x%x\n", addr);
+  return true;
+}
+
+void DumpEntry(const disk_cache::EntryStore& entry) {
+  std::string key;
+  if (!entry.long_key) {
+    key = entry.key;
+    if (key.size() > 50)
+      key.resize(50);
+  }
+
+  printf("hash: 0x%x\n", entry.hash);
+  printf("next entry: 0x%x\n", entry.next);
+  printf("rankings: 0x%x\n", entry.rankings_node);
+  printf("key length: %d\n", entry.key_len);
+  printf("key: \"%s\"\n", key.c_str());
+  printf("key addr: 0x%x\n", entry.long_key);
+  printf("data size 0: %d\n", entry.data_size[0]);
+  printf("data size 1: %d\n", entry.data_size[1]);
+  printf("data addr 0: 0x%x\n", entry.data_addr[0]);
+  printf("data addr 1: 0x%x\n", entry.data_addr[1]);
+  printf("----------\n\n");
+}
+
+void DumpRankings(const disk_cache::RankingsNode& rankings) {
+  printf("next: 0x%x\n", rankings.next);
+  printf("prev: 0x%x\n", rankings.prev);
+  printf("entry: 0x%x\n", rankings.contents);
+  printf("dirty: %d\n", rankings.dirty);
+  printf("pointer: 0x%x\n", rankings.pointer);
+  printf("----------\n\n");
+}
+
+}  // namespace.
+
+// -----------------------------------------------------------------------
+
+int GetMajorVersion(const std::wstring input_path) {
+  std::wstring index_name(input_path);
+  file_util::AppendToPath(&index_name, kIndexName);
+
+  int version = GetMajorVersionFromFile(index_name);
+  if (!version)
+    return 0;
+
+  std::wstring data_name(input_path);
+  file_util::AppendToPath(&data_name, L"data_0");
+  if (version != GetMajorVersionFromFile(data_name))
+    return 0;
+
+  data_name = input_path;
+  file_util::AppendToPath(&data_name, L"data_1");
+  if (version != GetMajorVersionFromFile(data_name))
+    return 0;
+
+  return version;
+}
+
+// Dumps the headers of all files.
+int DumpHeaders(const std::wstring input_path) {
+  std::wstring index_name(input_path);
+  file_util::AppendToPath(&index_name, kIndexName);
+  DumpIndexHeader(index_name);
+
+  std::wstring pattern(kDataPrefix);
+  pattern.append(L"*");
+  file_util::FileEnumerator iter(input_path, false,
+                                 file_util::FileEnumerator::FILES, pattern);
+  for (std::wstring file = iter.Next(); !file.empty(); file = iter.Next()) {
+    DumpBlockHeader(file);
+  }
+
+  return 0;
+}
+
+// Dumps all entries from the cache.
+int DumpContents(const std::wstring input_path) {
+  DumpHeaders(input_path);
+
+  // We need a message loop, although we really don't run any task.
+  MessageLoop loop(MessageLoop::TYPE_IO);
+  CacheDumper dumper(input_path);
+  if (!dumper.Init())
+    return -1;
+  
+  disk_cache::EntryStore entry;
+  while (dumper.GetEntry(&entry)) {
+    DumpEntry(entry);
+    disk_cache::RankingsNode rankings;
+    if (dumper.LoadRankings(entry.rankings_node, &rankings))
+      DumpRankings(rankings);
+  }
+
+  printf("Done.\n");
+
+  return 0;
+}