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#ifndef __UTIL_H
#define __UTIL_H
#include <string>
#include <vector>
#include <sstream>
#include <unistd.h>
extern "C" {
#include "md5.h"
}
using namespace std;
class Error : public exception
{
string err;
public:
Error(string _err) { err = _err; }
~Error() throw () { };
const char * what() const throw () { return err.c_str(); }
};
class UsageError : public Error
{
public:
UsageError(string _err) : Error(_err) { };
};
class BadRefError : public Error
{
public:
BadRefError(string _err) : Error(_err) { };
};
typedef vector<string> Strings;
/* !!! the following shouldn't be here; abuse of the preprocessor */
/* The canonical system name, as returned by config.guess. */
static string thisSystem = SYSTEM;
/* The prefix of the Nix installation, and the environment variable
that can be used to override the default. */
static string nixHomeDir = "/nix";
static string nixHomeDirEnvVar = "NIX";
string absPath(string filename, string dir = "")
{
if (filename[0] != '/') {
if (dir == "") {
char buf[PATH_MAX];
if (!getcwd(buf, sizeof(buf)))
throw Error("cannot get cwd");
dir = buf;
}
filename = dir + "/" + filename;
/* !!! canonicalise */
char resolved[PATH_MAX];
if (!realpath(filename.c_str(), resolved))
throw Error("cannot canonicalise path " + filename);
filename = resolved;
}
return filename;
}
string printHash(unsigned char * buf)
{
ostringstream str;
for (int i = 0; i < 16; i++) {
str.fill('0');
str.width(2);
str << hex << (int) buf[i];
}
return str.str();
}
/* Verify that a reference is valid (that is, is a MD5 hash code). */
bool isHash(const string & s)
{
if (s.length() != 32) return false;
for (int i = 0; i < 32; i++) {
char c = s[i];
if (!((c >= '0' && c <= '9') ||
(c >= 'a' && c <= 'f')))
return false;
}
return true;
}
void checkHash(const string & s)
{
if (!isHash(s)) throw BadRefError("invalid reference: " + s);
}
/* Compute the MD5 hash of a file. */
string hashFile(string filename)
{
unsigned char hash[16];
FILE * file = fopen(filename.c_str(), "rb");
if (!file)
throw BadRefError("file `" + filename + "' does not exist");
int err = md5_stream(file, hash);
fclose(file);
if (err) throw BadRefError("cannot hash file");
return printHash(hash);
}
/* Return the directory part of the given path, i.e., everything
before the final `/'. */
string dirOf(string s)
{
unsigned int pos = s.rfind('/');
if (pos == string::npos) throw Error("invalid file name");
return string(s, 0, pos);
}
/* Return the base name of the given path, i.e., everything following
the final `/'. */
string baseNameOf(string s)
{
unsigned int pos = s.rfind('/');
if (pos == string::npos) throw Error("invalid file name");
return string(s, pos + 1);
}
#endif /* !__UTIL_H */
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