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