lldb/source/Host/common/FileCache.cpp

   1 //===-- FileCache.cpp -----------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Host/FileCache.h"
  10
  11 #include "lldb/Host/File.h"
  12 #include "lldb/Host/FileSystem.h"
  13
  14 using namespace lldb;
  15 using namespace lldb_private;
  16
  17 FileCache *FileCache::m_instance = nullptr;
  18
  19 FileCache &FileCache::GetInstance() {
  20   if (m_instance == nullptr)
  21     m_instance = new FileCache();
  22
  23   return *m_instance;
  24 }
  25
  26 lldb::user_id_t FileCache::OpenFile(const FileSpec &file_spec,
  27                                     File::OpenOptions flags, uint32_t mode,
  28                                     Status &error) {
  29   if (!file_spec) {
  30     error = Status::FromErrorString("empty path");
  31     return UINT64_MAX;
  32   }
  33   auto file = FileSystem::Instance().Open(file_spec, flags, mode);
  34   if (!file) {
  35     error = Status::FromError(file.takeError());
  36     return UINT64_MAX;
  37   }
  38   lldb::user_id_t fd = file.get()->GetDescriptor();
  39   m_cache[fd] = std::move(file.get());
  40   return fd;
  41 }
  42
  43 bool FileCache::CloseFile(lldb::user_id_t fd, Status &error) {
  44   if (fd == UINT64_MAX) {
  45     error = Status::FromErrorString("invalid file descriptor");
  46     return false;
  47   }
  48   FDToFileMap::iterator pos = m_cache.find(fd);
  49   if (pos == m_cache.end()) {
  50     error = Status::FromErrorStringWithFormat(
  51         "invalid host file descriptor %" PRIu64, fd);
  52     return false;
  53   }
  54   FileUP &file_up = pos->second;
  55   if (!file_up) {
  56     error = Status::FromErrorString("invalid host backing file");
  57     return false;
  58   }
  59   error = file_up->Close();
  60   m_cache.erase(pos);
  61   return error.Success();
  62 }
  63
  64 uint64_t FileCache::WriteFile(lldb::user_id_t fd, uint64_t offset,
  65                               const void *src, uint64_t src_len,
  66                               Status &error) {
  67   if (fd == UINT64_MAX) {
  68     error = Status::FromErrorString("invalid file descriptor");
  69     return UINT64_MAX;
  70   }
  71   FDToFileMap::iterator pos = m_cache.find(fd);
  72   if (pos == m_cache.end()) {
  73     error = Status::FromErrorStringWithFormat(
  74         "invalid host file descriptor %" PRIu64, fd);
  75     return false;
  76   }
  77   FileUP &file_up = pos->second;
  78   if (!file_up) {
  79     error = Status::FromErrorString("invalid host backing file");
  80     return UINT64_MAX;
  81   }
  82   if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
  83       error.Fail())
  84     return UINT64_MAX;
  85   size_t bytes_written = src_len;
  86   error = file_up->Write(src, bytes_written);
  87   if (error.Fail())
  88     return UINT64_MAX;
  89   return bytes_written;
  90 }
  91
  92 uint64_t FileCache::ReadFile(lldb::user_id_t fd, uint64_t offset, void *dst,
  93                              uint64_t dst_len, Status &error) {
  94   if (fd == UINT64_MAX) {
  95     error = Status::FromErrorString("invalid file descriptor");
  96     return UINT64_MAX;
  97   }
  98   FDToFileMap::iterator pos = m_cache.find(fd);
  99   if (pos == m_cache.end()) {
 100     error = Status::FromErrorStringWithFormat(
 101         "invalid host file descriptor %" PRIu64, fd);
 102     return false;
 103   }
 104   FileUP &file_up = pos->second;
 105   if (!file_up) {
 106     error = Status::FromErrorString("invalid host backing file");
 107     return UINT64_MAX;
 108   }
 109   if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
 110       error.Fail())
 111     return UINT64_MAX;
 112   size_t bytes_read = dst_len;
 113   error = file_up->Read(dst, bytes_read);
 114   if (error.Fail())
 115     return UINT64_MAX;
 116   return bytes_read;
 117 }