mirror of https://github.com/ksherlock/mpw.git
145 lines
2.8 KiB
C++
145 lines
2.8 KiB
C++
#include "fs_spec.h"
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#include <algorithm>
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#include <cassert>
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#include <unistd.h>
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#include <sys/param.h>
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namespace OS {
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const int RootPathID = 2;
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std::deque<FSSpecManager::Entry> FSSpecManager::_pathQueue;
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void FSSpecManager::Init()
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{
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static bool initialized = false;
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if (!initialized)
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{
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// "/" is item #2. 0 and 1 are reserved.
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//can't just call IDForPath because that calls... Init();
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static std::string RootPath("/");
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std::hash<std::string> hasher;
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size_t hash = hasher(RootPath);
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_pathQueue.emplace_back(FSSpecManager::Entry(RootPath, hash));
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assert(_pathQueue.size() == 1);
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initialized = true;
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}
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}
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int32_t FSSpecManager::IDForCWD()
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{
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char buffer[MAXPATHLEN];
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char *cp;
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cp = getcwd(buffer, sizeof(buffer));
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if (cp < 0) return 0;
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std::string path(cp);
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return FSSpecManager::IDForPath(std::move(path), true);
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}
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int32_t FSSpecManager::IDForPath(const std::string &path, bool insert)
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{
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if (path.empty()) return -1;
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if (path.back() != '/')
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{
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std::string tmp(path);
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return IDForPath(std::move(tmp), insert);
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}
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/*
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char buffer[PATH_MAX + 1];
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char *cp = realpath(path.c_str(), buffer);
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if (!cp) return -1;
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std::string s(cp);
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*/
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std::hash<std::string> hasher;
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size_t hash = hasher(path);
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Init();
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// this only works well for a small number of directories,
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// which should be the common case.
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int i = RootPathID;
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for (const auto &e : _pathQueue)
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{
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if (e.hash == hash && e.path == path) return i;
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++i;
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}
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if (!insert) return -1;
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_pathQueue.emplace_back(FSSpecManager::Entry(path, hash));
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return _pathQueue.size() + RootPathID - 1;
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}
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int32_t FSSpecManager::IDForPath(std::string &&path, bool insert)
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{
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/*
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char buffer[PATH_MAX + 1];
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char *cp = realpath(path.c_str(), buffer);
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if (!cp) return -1;
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std::string s(cp);
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*/
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// trailing / is required.
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if (path.empty()) return -1;
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if (path.back() != '/') path.push_back('/');
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std::hash<std::string> hasher;
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size_t hash = hasher(path);
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Init();
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int i = RootPathID;
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for (const auto &e : _pathQueue)
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{
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if (e.hash == hash && e.path == path) return i;
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++i;
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}
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if (!insert) return -1;
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_pathQueue.emplace_back(FSSpecManager::Entry(std::move(path), hash));
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return _pathQueue.size() + RootPathID - 1;
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}
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const std::string &FSSpecManager::PathForID(int32_t id)
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{
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static std::string NullString;
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Init();
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id -= RootPathID;
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if (id < 0) return NullString;
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if (id >= _pathQueue.size()) return NullString;
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return _pathQueue[id].path;
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}
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std::string FSSpecManager::ExpandPath(const std::string &path, int32_t id)
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{
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if (path.length() && path.front() == '/') return path;
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if (id == 0) return path;
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const std::string &dir = PathForID(id);
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if (dir.empty()) return dir;
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return dir + path;
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}
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}
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