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.SetErrorString("empty path");
  31     return UINT64_MAX;
  32   }
  33   auto file = FileSystem::Instance().Open(file_spec, flags, mode);
  34   if (!file) {
  35     error = 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.SetErrorString("invalid file descriptor");
  46     return false;
  47   }
  48   FDToFileMap::iterator pos = m_cache.find(fd);
  49   if (pos == m_cache.end()) {
  50     error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
  51     return false;
  52   }
  53   FileUP &file_up = pos->second;
  54   if (!file_up) {
  55     error.SetErrorString("invalid host backing file");
  56     return false;
  57   }
  58   error = file_up->Close();
  59   m_cache.erase(pos);
  60   return error.Success();
  61 }
  62
  63 uint64_t FileCache::WriteFile(lldb::user_id_t fd, uint64_t offset,
  64                               const void *src, uint64_t src_len,
  65                               Status &error) {
  66   if (fd == UINT64_MAX) {
  67     error.SetErrorString("invalid file descriptor");
  68     return UINT64_MAX;
  69   }
  70   FDToFileMap::iterator pos = m_cache.find(fd);
  71   if (pos == m_cache.end()) {
  72     error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
  73     return false;
  74   }
  75   FileUP &file_up = pos->second;
  76   if (!file_up) {
  77     error.SetErrorString("invalid host backing file");
  78     return UINT64_MAX;
  79   }
  80   if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
  81       error.Fail())
  82     return UINT64_MAX;
  83   size_t bytes_written = src_len;
  84   error = file_up->Write(src, bytes_written);
  85   if (error.Fail())
  86     return UINT64_MAX;
  87   return bytes_written;
  88 }
  89
  90 uint64_t FileCache::ReadFile(lldb::user_id_t fd, uint64_t offset, void *dst,
  91                              uint64_t dst_len, Status &error) {
  92   if (fd == UINT64_MAX) {
  93     error.SetErrorString("invalid file descriptor");
  94     return UINT64_MAX;
  95   }
  96   FDToFileMap::iterator pos = m_cache.find(fd);
  97   if (pos == m_cache.end()) {
  98     error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
  99     return false;
 100   }
 101   FileUP &file_up = pos->second;
 102   if (!file_up) {
 103     error.SetErrorString("invalid host backing file");
 104     return UINT64_MAX;
 105   }
 106   if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
 107       error.Fail())
 108     return UINT64_MAX;
 109   size_t bytes_read = dst_len;
 110   error = file_up->Read(dst, bytes_read);
 111   if (error.Fail())
 112     return UINT64_MAX;
 113   return bytes_read;
 114 }