Mercurial > hg
view mercurial/pathencode.c @ 22178:70383c6961b4 stable
discovery: prevent crash on unknown remote heads with old repo (issue4337)
When a remote is not capable of the `branchmap` wireproto command, we denote
incoming heads with None. This leads to a crash in the code in charge of
displaying the list of unknown remote heads.
We now properly detect this case and display a shorter message in this case.
The reason for this `set([None])` value is now documented.
author | Pierre-Yves David <pierre-yves.david@fb.com> |
---|---|
date | Thu, 14 Aug 2014 16:26:41 -0700 |
parents | 5f683209f5b6 |
children | 822f46b80fa9 |
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/* pathencode.c - efficient path name encoding Copyright 2012 Facebook This software may be used and distributed according to the terms of the GNU General Public License, incorporated herein by reference. */ /* * An implementation of the name encoding scheme used by the fncache * store. The common case is of a path < 120 bytes long, which is * handled either in a single pass with no allocations or two passes * with a single allocation. For longer paths, multiple passes are * required. */ #define PY_SSIZE_T_CLEAN #include <Python.h> #include <assert.h> #include <ctype.h> #include <stdlib.h> #include <string.h> #include "util.h" /* state machine for the fast path */ enum path_state { START, /* first byte of a path component */ A, /* "AUX" */ AU, THIRD, /* third of a 3-byte sequence, e.g. "AUX", "NUL" */ C, /* "CON" or "COMn" */ CO, COMLPT, /* "COM" or "LPT" */ COMLPTn, L, LP, N, NU, P, /* "PRN" */ PR, LDOT, /* leading '.' */ DOT, /* '.' in a non-leading position */ H, /* ".h" */ HGDI, /* ".hg", ".d", or ".i" */ SPACE, DEFAULT /* byte of a path component after the first */ }; /* state machine for dir-encoding */ enum dir_state { DDOT, DH, DHGDI, DDEFAULT }; static inline int inset(const uint32_t bitset[], char c) { return bitset[((uint8_t)c) >> 5] & (1 << (((uint8_t)c) & 31)); } static inline void charcopy(char *dest, Py_ssize_t *destlen, size_t destsize, char c) { if (dest) { assert(*destlen < destsize); dest[*destlen] = c; } (*destlen)++; } static inline void memcopy(char *dest, Py_ssize_t *destlen, size_t destsize, const void *src, Py_ssize_t len) { if (dest) { assert(*destlen + len < destsize); memcpy((void *)&dest[*destlen], src, len); } *destlen += len; } static inline void hexencode(char *dest, Py_ssize_t *destlen, size_t destsize, uint8_t c) { static const char hexdigit[] = "0123456789abcdef"; charcopy(dest, destlen, destsize, hexdigit[c >> 4]); charcopy(dest, destlen, destsize, hexdigit[c & 15]); } /* 3-byte escape: tilde followed by two hex digits */ static inline void escape3(char *dest, Py_ssize_t *destlen, size_t destsize, char c) { charcopy(dest, destlen, destsize, '~'); hexencode(dest, destlen, destsize, c); } static Py_ssize_t _encodedir(char *dest, size_t destsize, const char *src, Py_ssize_t len) { enum dir_state state = DDEFAULT; Py_ssize_t i = 0, destlen = 0; while (i < len) { switch (state) { case DDOT: switch (src[i]) { case 'd': case 'i': state = DHGDI; charcopy(dest, &destlen, destsize, src[i++]); break; case 'h': state = DH; charcopy(dest, &destlen, destsize, src[i++]); break; default: state = DDEFAULT; break; } break; case DH: if (src[i] == 'g') { state = DHGDI; charcopy(dest, &destlen, destsize, src[i++]); } else state = DDEFAULT; break; case DHGDI: if (src[i] == '/') { memcopy(dest, &destlen, destsize, ".hg", 3); charcopy(dest, &destlen, destsize, src[i++]); } state = DDEFAULT; break; case DDEFAULT: if (src[i] == '.') state = DDOT; charcopy(dest, &destlen, destsize, src[i++]); break; } } return destlen; } PyObject *encodedir(PyObject *self, PyObject *args) { Py_ssize_t len, newlen; PyObject *pathobj, *newobj; char *path; if (!PyArg_ParseTuple(args, "O:encodedir", &pathobj)) return NULL; if (PyString_AsStringAndSize(pathobj, &path, &len) == -1) { PyErr_SetString(PyExc_TypeError, "expected a string"); return NULL; } newlen = len ? _encodedir(NULL, 0, path, len + 1) : 1; if (newlen == len + 1) { Py_INCREF(pathobj); return pathobj; } newobj = PyString_FromStringAndSize(NULL, newlen); if (newobj) { PyString_GET_SIZE(newobj)--; _encodedir(PyString_AS_STRING(newobj), newlen, path, len + 1); } return newobj; } static Py_ssize_t _encode(const uint32_t twobytes[8], const uint32_t onebyte[8], char *dest, Py_ssize_t destlen, size_t destsize, const char *src, Py_ssize_t len, int encodedir) { enum path_state state = START; Py_ssize_t i = 0; /* * Python strings end with a zero byte, which we use as a * terminal token as they are not valid inside path names. */ while (i < len) { switch (state) { case START: switch (src[i]) { case '/': charcopy(dest, &destlen, destsize, src[i++]); break; case '.': state = LDOT; escape3(dest, &destlen, destsize, src[i++]); break; case ' ': state = DEFAULT; escape3(dest, &destlen, destsize, src[i++]); break; case 'a': state = A; charcopy(dest, &destlen, destsize, src[i++]); break; case 'c': state = C; charcopy(dest, &destlen, destsize, src[i++]); break; case 'l': state = L; charcopy(dest, &destlen, destsize, src[i++]); break; case 'n': state = N; charcopy(dest, &destlen, destsize, src[i++]); break; case 'p': state = P; charcopy(dest, &destlen, destsize, src[i++]); break; default: state = DEFAULT; break; } break; case A: if (src[i] == 'u') { state = AU; charcopy(dest, &destlen, destsize, src[i++]); } else state = DEFAULT; break; case AU: if (src[i] == 'x') { state = THIRD; i++; } else state = DEFAULT; break; case THIRD: state = DEFAULT; switch (src[i]) { case '.': case '/': case '\0': escape3(dest, &destlen, destsize, src[i - 1]); break; default: i--; break; } break; case C: if (src[i] == 'o') { state = CO; charcopy(dest, &destlen, destsize, src[i++]); } else state = DEFAULT; break; case CO: if (src[i] == 'm') { state = COMLPT; i++; } else if (src[i] == 'n') { state = THIRD; i++; } else state = DEFAULT; break; case COMLPT: switch (src[i]) { case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': state = COMLPTn; i++; break; default: state = DEFAULT; charcopy(dest, &destlen, destsize, src[i - 1]); break; } break; case COMLPTn: state = DEFAULT; switch (src[i]) { case '.': case '/': case '\0': escape3(dest, &destlen, destsize, src[i - 2]); charcopy(dest, &destlen, destsize, src[i - 1]); break; default: memcopy(dest, &destlen, destsize, &src[i - 2], 2); break; } break; case L: if (src[i] == 'p') { state = LP; charcopy(dest, &destlen, destsize, src[i++]); } else state = DEFAULT; break; case LP: if (src[i] == 't') { state = COMLPT; i++; } else state = DEFAULT; break; case N: if (src[i] == 'u') { state = NU; charcopy(dest, &destlen, destsize, src[i++]); } else state = DEFAULT; break; case NU: if (src[i] == 'l') { state = THIRD; i++; } else state = DEFAULT; break; case P: if (src[i] == 'r') { state = PR; charcopy(dest, &destlen, destsize, src[i++]); } else state = DEFAULT; break; case PR: if (src[i] == 'n') { state = THIRD; i++; } else state = DEFAULT; break; case LDOT: switch (src[i]) { case 'd': case 'i': state = HGDI; charcopy(dest, &destlen, destsize, src[i++]); break; case 'h': state = H; charcopy(dest, &destlen, destsize, src[i++]); break; default: state = DEFAULT; break; } break; case DOT: switch (src[i]) { case '/': case '\0': state = START; memcopy(dest, &destlen, destsize, "~2e", 3); charcopy(dest, &destlen, destsize, src[i++]); break; case 'd': case 'i': state = HGDI; charcopy(dest, &destlen, destsize, '.'); charcopy(dest, &destlen, destsize, src[i++]); break; case 'h': state = H; memcopy(dest, &destlen, destsize, ".h", 2); i++; break; default: state = DEFAULT; charcopy(dest, &destlen, destsize, '.'); break; } break; case H: if (src[i] == 'g') { state = HGDI; charcopy(dest, &destlen, destsize, src[i++]); } else state = DEFAULT; break; case HGDI: if (src[i] == '/') { state = START; if (encodedir) memcopy(dest, &destlen, destsize, ".hg", 3); charcopy(dest, &destlen, destsize, src[i++]); } else state = DEFAULT; break; case SPACE: switch (src[i]) { case '/': case '\0': state = START; memcopy(dest, &destlen, destsize, "~20", 3); charcopy(dest, &destlen, destsize, src[i++]); break; default: state = DEFAULT; charcopy(dest, &destlen, destsize, ' '); break; } break; case DEFAULT: while (inset(onebyte, src[i])) { charcopy(dest, &destlen, destsize, src[i++]); if (i == len) goto done; } switch (src[i]) { case '.': state = DOT; i++; break; case ' ': state = SPACE; i++; break; case '/': state = START; charcopy(dest, &destlen, destsize, '/'); i++; break; default: if (inset(onebyte, src[i])) { do { charcopy(dest, &destlen, destsize, src[i++]); } while (i < len && inset(onebyte, src[i])); } else if (inset(twobytes, src[i])) { char c = src[i++]; charcopy(dest, &destlen, destsize, '_'); charcopy(dest, &destlen, destsize, c == '_' ? '_' : c + 32); } else escape3(dest, &destlen, destsize, src[i++]); break; } break; } } done: return destlen; } static Py_ssize_t basicencode(char *dest, size_t destsize, const char *src, Py_ssize_t len) { static const uint32_t twobytes[8] = { 0, 0, 0x87fffffe }; static const uint32_t onebyte[8] = { 1, 0x2bff3bfa, 0x68000001, 0x2fffffff, }; Py_ssize_t destlen = 0; return _encode(twobytes, onebyte, dest, destlen, destsize, src, len, 1); } static const Py_ssize_t maxstorepathlen = 120; static Py_ssize_t _lowerencode(char *dest, size_t destsize, const char *src, Py_ssize_t len) { static const uint32_t onebyte[8] = { 1, 0x2bfffbfb, 0xe8000001, 0x2fffffff }; static const uint32_t lower[8] = { 0, 0, 0x7fffffe }; Py_ssize_t i, destlen = 0; for (i = 0; i < len; i++) { if (inset(onebyte, src[i])) charcopy(dest, &destlen, destsize, src[i]); else if (inset(lower, src[i])) charcopy(dest, &destlen, destsize, src[i] + 32); else escape3(dest, &destlen, destsize, src[i]); } return destlen; } PyObject *lowerencode(PyObject *self, PyObject *args) { char *path; Py_ssize_t len, newlen; PyObject *ret; if (!PyArg_ParseTuple(args, "s#:lowerencode", &path, &len)) return NULL; newlen = _lowerencode(NULL, 0, path, len); ret = PyString_FromStringAndSize(NULL, newlen); if (ret) newlen = _lowerencode(PyString_AS_STRING(ret), newlen, path, len); return ret; } /* See store.py:_auxencode for a description. */ static Py_ssize_t auxencode(char *dest, size_t destsize, const char *src, Py_ssize_t len) { static const uint32_t twobytes[8]; static const uint32_t onebyte[8] = { ~0U, 0xffff3ffe, ~0U, ~0U, ~0U, ~0U, ~0U, ~0U, }; return _encode(twobytes, onebyte, dest, 0, destsize, src, len, 0); } static PyObject *hashmangle(const char *src, Py_ssize_t len, const char sha[20]) { static const Py_ssize_t dirprefixlen = 8; static const Py_ssize_t maxshortdirslen = 68; char *dest; PyObject *ret; Py_ssize_t i, d, p, lastslash = len - 1, lastdot = -1; Py_ssize_t destsize, destlen = 0, slop, used; while (lastslash >= 0 && src[lastslash] != '/') { if (src[lastslash] == '.' && lastdot == -1) lastdot = lastslash; lastslash--; } #if 0 /* All paths should end in a suffix of ".i" or ".d". Unfortunately, the file names in test-hybridencode.py violate this rule. */ if (lastdot != len - 3) { PyErr_SetString(PyExc_ValueError, "suffix missing or wrong length"); return NULL; } #endif /* If src contains a suffix, we will append it to the end of the new string, so make room. */ destsize = 120; if (lastdot >= 0) destsize += len - lastdot - 1; ret = PyString_FromStringAndSize(NULL, destsize); if (ret == NULL) return NULL; dest = PyString_AS_STRING(ret); memcopy(dest, &destlen, destsize, "dh/", 3); /* Copy up to dirprefixlen bytes of each path component, up to a limit of maxshortdirslen bytes. */ for (i = d = p = 0; i < lastslash; i++, p++) { if (src[i] == '/') { char d = dest[destlen - 1]; /* After truncation, a directory name may end in a space or dot, which are unportable. */ if (d == '.' || d == ' ') dest[destlen - 1] = '_'; /* The + 3 is to account for "dh/" in the beginning */ if (destlen > maxshortdirslen + 3) break; charcopy(dest, &destlen, destsize, src[i]); p = -1; } else if (p < dirprefixlen) charcopy(dest, &destlen, destsize, src[i]); } /* Rewind to just before the last slash copied. */ if (destlen > maxshortdirslen + 3) do { destlen--; } while (destlen > 0 && dest[destlen] != '/'); if (destlen > 3) { if (lastslash > 0) { char d = dest[destlen - 1]; /* The last directory component may be truncated, so make it safe. */ if (d == '.' || d == ' ') dest[destlen - 1] = '_'; } charcopy(dest, &destlen, destsize, '/'); } /* Add a prefix of the original file's name. Its length depends on the number of bytes left after accounting for hash and suffix. */ used = destlen + 40; if (lastdot >= 0) used += len - lastdot - 1; slop = maxstorepathlen - used; if (slop > 0) { Py_ssize_t basenamelen = lastslash >= 0 ? len - lastslash - 2 : len - 1; if (basenamelen > slop) basenamelen = slop; if (basenamelen > 0) memcopy(dest, &destlen, destsize, &src[lastslash + 1], basenamelen); } /* Add hash and suffix. */ for (i = 0; i < 20; i++) hexencode(dest, &destlen, destsize, sha[i]); if (lastdot >= 0) memcopy(dest, &destlen, destsize, &src[lastdot], len - lastdot - 1); PyString_GET_SIZE(ret) = destlen; return ret; } /* * Avoiding a trip through Python would improve performance by 50%, * but we don't encounter enough long names to be worth the code. */ static int sha1hash(char hash[20], const char *str, Py_ssize_t len) { static PyObject *shafunc; PyObject *shaobj, *hashobj; if (shafunc == NULL) { PyObject *util, *name = PyString_FromString("mercurial.util"); if (name == NULL) return -1; util = PyImport_Import(name); Py_DECREF(name); if (util == NULL) { PyErr_SetString(PyExc_ImportError, "mercurial.util"); return -1; } shafunc = PyObject_GetAttrString(util, "sha1"); Py_DECREF(util); if (shafunc == NULL) { PyErr_SetString(PyExc_AttributeError, "module 'mercurial.util' has no " "attribute 'sha1'"); return -1; } } shaobj = PyObject_CallFunction(shafunc, "s#", str, len); if (shaobj == NULL) return -1; hashobj = PyObject_CallMethod(shaobj, "digest", ""); Py_DECREF(shaobj); if (!PyString_Check(hashobj) || PyString_GET_SIZE(hashobj) != 20) { PyErr_SetString(PyExc_TypeError, "result of digest is not a 20-byte hash"); Py_DECREF(hashobj); return -1; } memcpy(hash, PyString_AS_STRING(hashobj), 20); Py_DECREF(hashobj); return 0; } #define MAXENCODE 4096 * 4 static PyObject *hashencode(const char *src, Py_ssize_t len) { char dired[MAXENCODE]; char lowered[MAXENCODE]; char auxed[MAXENCODE]; Py_ssize_t dirlen, lowerlen, auxlen, baselen; char sha[20]; baselen = (len - 5) * 3; if (baselen >= MAXENCODE) { PyErr_SetString(PyExc_ValueError, "string too long"); return NULL; } dirlen = _encodedir(dired, baselen, src, len); if (sha1hash(sha, dired, dirlen - 1) == -1) return NULL; lowerlen = _lowerencode(lowered, baselen, dired + 5, dirlen - 5); auxlen = auxencode(auxed, baselen, lowered, lowerlen); return hashmangle(auxed, auxlen, sha); } PyObject *pathencode(PyObject *self, PyObject *args) { Py_ssize_t len, newlen; PyObject *pathobj, *newobj; char *path; if (!PyArg_ParseTuple(args, "O:pathencode", &pathobj)) return NULL; if (PyString_AsStringAndSize(pathobj, &path, &len) == -1) { PyErr_SetString(PyExc_TypeError, "expected a string"); return NULL; } if (len > maxstorepathlen) newlen = maxstorepathlen + 2; else newlen = len ? basicencode(NULL, 0, path, len + 1) : 1; if (newlen <= maxstorepathlen + 1) { if (newlen == len + 1) { Py_INCREF(pathobj); return pathobj; } newobj = PyString_FromStringAndSize(NULL, newlen); if (newobj) { PyString_GET_SIZE(newobj)--; basicencode(PyString_AS_STRING(newobj), newlen, path, len + 1); } } else newobj = hashencode(path, len + 1); return newobj; }