Files
clang-p2996/lldb/source/Host/common/FileSystem.cpp
Zachary Turner 82a0c97b32 Add a function to MD5 a file's contents.
In doing so, clean up the MD5 interface a little.  Most
existing users only care about the lower 8 bytes of an MD5,
but for some users that care about the upper and lower,
there wasn't a good interface.  Furthermore, consumers
of the MD5 checksum were required to handle endianness
details on their own, so it seems reasonable to abstract
this into a nicer interface that just gives you the right
value.

Differential Revision: https://reviews.llvm.org/D31105

llvm-svn: 298322
2017-03-20 23:33:18 +00:00

101 lines
2.9 KiB
C++

//===-- FileSystem.cpp ------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lldb/Host/FileSystem.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MD5.h"
#include <algorithm>
#include <fstream>
#include <vector>
using namespace lldb;
using namespace lldb_private;
namespace {
bool CalcMD5(const FileSpec &file_spec, uint64_t offset, uint64_t length,
llvm::MD5::MD5Result &md5_result) {
llvm::MD5 md5_hash;
std::ifstream file(file_spec.GetPath(), std::ios::binary);
if (!file.is_open())
return false;
if (offset > 0)
file.seekg(offset, file.beg);
std::vector<char> read_buf(4096);
uint64_t total_read_bytes = 0;
while (!file.eof()) {
const uint64_t to_read =
(length > 0) ? std::min(static_cast<uint64_t>(read_buf.size()),
length - total_read_bytes)
: read_buf.size();
if (to_read == 0)
break;
file.read(&read_buf[0], to_read);
const auto read_bytes = file.gcount();
if (read_bytes == 0)
break;
md5_hash.update(llvm::StringRef(&read_buf[0], read_bytes));
total_read_bytes += read_bytes;
}
md5_hash.final(md5_result);
return true;
}
} // namespace
bool FileSystem::CalculateMD5(const FileSpec &file_spec, uint64_t &low,
uint64_t &high) {
return CalculateMD5(file_spec, 0, 0, low, high);
}
bool FileSystem::CalculateMD5(const FileSpec &file_spec, uint64_t offset,
uint64_t length, uint64_t &low, uint64_t &high) {
llvm::MD5::MD5Result md5_result;
if (!CalcMD5(file_spec, offset, length, md5_result))
return false;
std::tie(high, low) = md5_result.words();
return true;
}
bool FileSystem::CalculateMD5AsString(const FileSpec &file_spec,
std::string &digest_str) {
return CalculateMD5AsString(file_spec, 0, 0, digest_str);
}
bool FileSystem::CalculateMD5AsString(const FileSpec &file_spec,
uint64_t offset, uint64_t length,
std::string &digest_str) {
llvm::MD5::MD5Result md5_result;
if (!CalcMD5(file_spec, offset, length, md5_result))
return false;
llvm::SmallString<32> result_str;
llvm::MD5::stringifyResult(md5_result, result_str);
digest_str = result_str.c_str();
return true;
}
llvm::sys::TimePoint<>
FileSystem::GetModificationTime(const FileSpec &file_spec) {
llvm::sys::fs::file_status status;
std::error_code ec = llvm::sys::fs::status(file_spec.GetPath(), status);
if (ec)
return llvm::sys::TimePoint<>();
return status.getLastModificationTime();
}