Mercurial > hg
view mercurial/manifest.c @ 26669:07db7e95c464
rebase: added comments
Added comments describing the state variable and constants used throughout the
rebase extension
author | Christian Delahousse <cdelahousse@fb.com> |
---|---|
date | Tue, 13 Oct 2015 14:17:15 -0700 |
parents | 89c2bf63a83b |
children | 7b8b6e3b3571 |
line wrap: on
line source
/* * manifest.c - manifest type that does on-demand parsing. * * Copyright 2015, Google Inc. * * This software may be used and distributed according to the terms of * the GNU General Public License, incorporated herein by reference. */ #include <Python.h> #include <assert.h> #include <string.h> #include <stdlib.h> #include "util.h" #define DEFAULT_LINES 100000 typedef struct { char *start; Py_ssize_t len; /* length of line including terminal newline */ char hash_suffix; bool from_malloc; bool deleted; } line; typedef struct { PyObject_HEAD PyObject *pydata; line *lines; int numlines; /* number of line entries */ int livelines; /* number of non-deleted lines */ int maxlines; /* allocated number of lines */ bool dirty; } lazymanifest; #define MANIFEST_OOM -1 #define MANIFEST_NOT_SORTED -2 #define MANIFEST_MALFORMED -3 /* defined in parsers.c */ PyObject *unhexlify(const char *str, int len); /* get the length of the path for a line */ static size_t pathlen(line *l) { return strlen(l->start); } /* get the node value of a single line */ static PyObject *nodeof(line *l) { char *s = l->start; ssize_t llen = pathlen(l); PyObject *hash = unhexlify(s + llen + 1, 40); if (!hash) { return NULL; } if (l->hash_suffix != '\0') { char newhash[21]; memcpy(newhash, PyString_AsString(hash), 20); Py_DECREF(hash); newhash[20] = l->hash_suffix; hash = PyString_FromStringAndSize(newhash, 21); } return hash; } /* get the node hash and flags of a line as a tuple */ static PyObject *hashflags(line *l) { char *s = l->start; size_t plen = pathlen(l); PyObject *hash = nodeof(l); /* 40 for hash, 1 for null byte, 1 for newline */ size_t hplen = plen + 42; Py_ssize_t flen = l->len - hplen; PyObject *flags; PyObject *tup; if (!hash) return NULL; flags = PyString_FromStringAndSize(s + hplen - 1, flen); if (!flags) { Py_DECREF(hash); return NULL; } tup = PyTuple_Pack(2, hash, flags); Py_DECREF(flags); Py_DECREF(hash); return tup; } /* if we're about to run out of space in the line index, add more */ static bool realloc_if_full(lazymanifest *self) { if (self->numlines == self->maxlines) { self->maxlines *= 2; self->lines = realloc(self->lines, self->maxlines * sizeof(line)); } return !!self->lines; } /* * Find the line boundaries in the manifest that 'data' points to and store * information about each line in 'self'. */ static int find_lines(lazymanifest *self, char *data, Py_ssize_t len) { char *prev = NULL; while (len > 0) { line *l; char *next = memchr(data, '\n', len); if (!next) { return MANIFEST_MALFORMED; } next++; /* advance past newline */ if (!realloc_if_full(self)) { return MANIFEST_OOM; /* no memory */ } if (prev && strcmp(prev, data) > -1) { /* This data isn't sorted, so we have to abort. */ return MANIFEST_NOT_SORTED; } l = self->lines + ((self->numlines)++); l->start = data; l->len = next - data; l->hash_suffix = '\0'; l->from_malloc = false; l->deleted = false; len = len - l->len; prev = data; data = next; } self->livelines = self->numlines; return 0; } static int lazymanifest_init(lazymanifest *self, PyObject *args) { char *data; Py_ssize_t len; int err, ret; PyObject *pydata; if (!PyArg_ParseTuple(args, "S", &pydata)) { return -1; } err = PyString_AsStringAndSize(pydata, &data, &len); self->dirty = false; if (err == -1) return -1; self->pydata = pydata; Py_INCREF(self->pydata); Py_BEGIN_ALLOW_THREADS self->lines = malloc(DEFAULT_LINES * sizeof(line)); self->maxlines = DEFAULT_LINES; self->numlines = 0; if (!self->lines) ret = MANIFEST_OOM; else ret = find_lines(self, data, len); Py_END_ALLOW_THREADS switch (ret) { case 0: break; case MANIFEST_OOM: PyErr_NoMemory(); break; case MANIFEST_NOT_SORTED: PyErr_Format(PyExc_ValueError, "Manifest lines not in sorted order."); break; case MANIFEST_MALFORMED: PyErr_Format(PyExc_ValueError, "Manifest did not end in a newline."); break; default: PyErr_Format(PyExc_ValueError, "Unknown problem parsing manifest."); } return ret == 0 ? 0 : -1; } static void lazymanifest_dealloc(lazymanifest *self) { /* free any extra lines we had to allocate */ int i; for (i = 0; i < self->numlines; i++) { if (self->lines[i].from_malloc) { free(self->lines[i].start); } } if (self->lines) { free(self->lines); self->lines = NULL; } if (self->pydata) { Py_DECREF(self->pydata); self->pydata = NULL; } PyObject_Del(self); } /* iteration support */ typedef struct { PyObject_HEAD lazymanifest *m; Py_ssize_t pos; } lmIter; static void lmiter_dealloc(PyObject *o) { lmIter *self = (lmIter *)o; Py_DECREF(self->m); PyObject_Del(self); } static line *lmiter_nextline(lmIter *self) { do { self->pos++; if (self->pos >= self->m->numlines) { return NULL; } /* skip over deleted manifest entries */ } while (self->m->lines[self->pos].deleted); return self->m->lines + self->pos; } static PyObject *lmiter_iterentriesnext(PyObject *o) { size_t pl; line *l; Py_ssize_t consumed; PyObject *ret = NULL, *path = NULL, *hash = NULL, *flags = NULL; l = lmiter_nextline((lmIter *)o); if (!l) { goto done; } pl = pathlen(l); path = PyString_FromStringAndSize(l->start, pl); hash = nodeof(l); consumed = pl + 41; flags = PyString_FromStringAndSize(l->start + consumed, l->len - consumed - 1); if (!path || !hash || !flags) { goto done; } ret = PyTuple_Pack(3, path, hash, flags); done: Py_XDECREF(path); Py_XDECREF(hash); Py_XDECREF(flags); return ret; } static PyTypeObject lazymanifestEntriesIterator = { PyObject_HEAD_INIT(NULL) 0, /*ob_size */ "parsers.lazymanifest.entriesiterator", /*tp_name */ sizeof(lmIter), /*tp_basicsize */ 0, /*tp_itemsize */ lmiter_dealloc, /*tp_dealloc */ 0, /*tp_print */ 0, /*tp_getattr */ 0, /*tp_setattr */ 0, /*tp_compare */ 0, /*tp_repr */ 0, /*tp_as_number */ 0, /*tp_as_sequence */ 0, /*tp_as_mapping */ 0, /*tp_hash */ 0, /*tp_call */ 0, /*tp_str */ 0, /*tp_getattro */ 0, /*tp_setattro */ 0, /*tp_as_buffer */ /* tp_flags: Py_TPFLAGS_HAVE_ITER tells python to use tp_iter and tp_iternext fields. */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, "Iterator for 3-tuples in a lazymanifest.", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ 0, /* tp_richcompare */ 0, /* tp_weaklistoffset */ PyObject_SelfIter, /* tp_iter: __iter__() method */ lmiter_iterentriesnext, /* tp_iternext: next() method */ }; static PyObject *lmiter_iterkeysnext(PyObject *o) { size_t pl; line *l = lmiter_nextline((lmIter *)o); if (!l) { return NULL; } pl = pathlen(l); return PyString_FromStringAndSize(l->start, pl); } static PyTypeObject lazymanifestKeysIterator = { PyObject_HEAD_INIT(NULL) 0, /*ob_size */ "parsers.lazymanifest.keysiterator", /*tp_name */ sizeof(lmIter), /*tp_basicsize */ 0, /*tp_itemsize */ lmiter_dealloc, /*tp_dealloc */ 0, /*tp_print */ 0, /*tp_getattr */ 0, /*tp_setattr */ 0, /*tp_compare */ 0, /*tp_repr */ 0, /*tp_as_number */ 0, /*tp_as_sequence */ 0, /*tp_as_mapping */ 0, /*tp_hash */ 0, /*tp_call */ 0, /*tp_str */ 0, /*tp_getattro */ 0, /*tp_setattro */ 0, /*tp_as_buffer */ /* tp_flags: Py_TPFLAGS_HAVE_ITER tells python to use tp_iter and tp_iternext fields. */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, "Keys iterator for a lazymanifest.", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ 0, /* tp_richcompare */ 0, /* tp_weaklistoffset */ PyObject_SelfIter, /* tp_iter: __iter__() method */ lmiter_iterkeysnext, /* tp_iternext: next() method */ }; static lazymanifest *lazymanifest_copy(lazymanifest *self); static PyObject *lazymanifest_getentriesiter(lazymanifest *self) { lmIter *i = NULL; lazymanifest *t = lazymanifest_copy(self); if (!t) { PyErr_NoMemory(); return NULL; } i = PyObject_New(lmIter, &lazymanifestEntriesIterator); if (i) { i->m = t; i->pos = -1; } else { Py_DECREF(t); PyErr_NoMemory(); } return (PyObject *)i; } static PyObject *lazymanifest_getkeysiter(lazymanifest *self) { lmIter *i = NULL; lazymanifest *t = lazymanifest_copy(self); if (!t) { PyErr_NoMemory(); return NULL; } i = PyObject_New(lmIter, &lazymanifestKeysIterator); if (i) { i->m = t; i->pos = -1; } else { Py_DECREF(t); PyErr_NoMemory(); } return (PyObject *)i; } /* __getitem__ and __setitem__ support */ static Py_ssize_t lazymanifest_size(lazymanifest *self) { return self->livelines; } static int linecmp(const void *left, const void *right) { return strcmp(((const line *)left)->start, ((const line *)right)->start); } static PyObject *lazymanifest_getitem(lazymanifest *self, PyObject *key) { line needle; line *hit; if (!PyString_Check(key)) { PyErr_Format(PyExc_TypeError, "getitem: manifest keys must be a string."); return NULL; } needle.start = PyString_AsString(key); hit = bsearch(&needle, self->lines, self->numlines, sizeof(line), &linecmp); if (!hit || hit->deleted) { PyErr_Format(PyExc_KeyError, "No such manifest entry."); return NULL; } return hashflags(hit); } static int lazymanifest_delitem(lazymanifest *self, PyObject *key) { line needle; line *hit; if (!PyString_Check(key)) { PyErr_Format(PyExc_TypeError, "delitem: manifest keys must be a string."); return -1; } needle.start = PyString_AsString(key); hit = bsearch(&needle, self->lines, self->numlines, sizeof(line), &linecmp); if (!hit || hit->deleted) { PyErr_Format(PyExc_KeyError, "Tried to delete nonexistent manifest entry."); return -1; } self->dirty = true; hit->deleted = true; self->livelines--; return 0; } /* Do a binary search for the insertion point for new, creating the * new entry if needed. */ static int internalsetitem(lazymanifest *self, line *new) { int start = 0, end = self->numlines; while (start < end) { int pos = start + (end - start) / 2; int c = linecmp(new, self->lines + pos); if (c < 0) end = pos; else if (c > 0) start = pos + 1; else { if (self->lines[pos].deleted) self->livelines++; if (self->lines[pos].from_malloc) free(self->lines[pos].start); start = pos; goto finish; } } /* being here means we need to do an insert */ if (!realloc_if_full(self)) { PyErr_NoMemory(); return -1; } memmove(self->lines + start + 1, self->lines + start, (self->numlines - start) * sizeof(line)); self->numlines++; self->livelines++; finish: self->lines[start] = *new; self->dirty = true; return 0; } static int lazymanifest_setitem( lazymanifest *self, PyObject *key, PyObject *value) { char *path; Py_ssize_t plen; PyObject *pyhash; Py_ssize_t hlen; char *hash; PyObject *pyflags; char *flags; Py_ssize_t flen; size_t dlen; char *dest; int i; line new; if (!PyString_Check(key)) { PyErr_Format(PyExc_TypeError, "setitem: manifest keys must be a string."); return -1; } if (!value) { return lazymanifest_delitem(self, key); } if (!PyTuple_Check(value) || PyTuple_Size(value) != 2) { PyErr_Format(PyExc_TypeError, "Manifest values must be a tuple of (node, flags)."); return -1; } if (PyString_AsStringAndSize(key, &path, &plen) == -1) { return -1; } pyhash = PyTuple_GetItem(value, 0); if (!PyString_Check(pyhash)) { PyErr_Format(PyExc_TypeError, "node must be a 20-byte string"); return -1; } hlen = PyString_Size(pyhash); /* Some parts of the codebase try and set 21 or 22 * byte "hash" values in order to perturb things for * status. We have to preserve at least the 21st * byte. Sigh. If there's a 22nd byte, we drop it on * the floor, which works fine. */ if (hlen != 20 && hlen != 21 && hlen != 22) { PyErr_Format(PyExc_TypeError, "node must be a 20-byte string"); return -1; } hash = PyString_AsString(pyhash); pyflags = PyTuple_GetItem(value, 1); if (!PyString_Check(pyflags) || PyString_Size(pyflags) > 1) { PyErr_Format(PyExc_TypeError, "flags must a 0 or 1 byte string"); return -1; } if (PyString_AsStringAndSize(pyflags, &flags, &flen) == -1) { return -1; } /* one null byte and one newline */ dlen = plen + 41 + flen + 1; dest = malloc(dlen); if (!dest) { PyErr_NoMemory(); return -1; } memcpy(dest, path, plen + 1); for (i = 0; i < 20; i++) { /* Cast to unsigned, so it will not get sign-extended when promoted * to int (as is done when passing to a variadic function) */ sprintf(dest + plen + 1 + (i * 2), "%02x", (unsigned char)hash[i]); } memcpy(dest + plen + 41, flags, flen); dest[plen + 41 + flen] = '\n'; new.start = dest; new.len = dlen; new.hash_suffix = '\0'; if (hlen > 20) { new.hash_suffix = hash[20]; } new.from_malloc = true; /* is `start` a pointer we allocated? */ new.deleted = false; /* is this entry deleted? */ if (internalsetitem(self, &new)) { return -1; } return 0; } static PyMappingMethods lazymanifest_mapping_methods = { (lenfunc)lazymanifest_size, /* mp_length */ (binaryfunc)lazymanifest_getitem, /* mp_subscript */ (objobjargproc)lazymanifest_setitem, /* mp_ass_subscript */ }; /* sequence methods (important or __contains__ builds an iterator */ static int lazymanifest_contains(lazymanifest *self, PyObject *key) { line needle; line *hit; if (!PyString_Check(key)) { /* Our keys are always strings, so if the contains * check is for a non-string, just return false. */ return 0; } needle.start = PyString_AsString(key); hit = bsearch(&needle, self->lines, self->numlines, sizeof(line), &linecmp); if (!hit || hit->deleted) { return 0; } return 1; } static PySequenceMethods lazymanifest_seq_meths = { (lenfunc)lazymanifest_size, /* sq_length */ 0, /* sq_concat */ 0, /* sq_repeat */ 0, /* sq_item */ 0, /* sq_slice */ 0, /* sq_ass_item */ 0, /* sq_ass_slice */ (objobjproc)lazymanifest_contains, /* sq_contains */ 0, /* sq_inplace_concat */ 0, /* sq_inplace_repeat */ }; /* Other methods (copy, diff, etc) */ static PyTypeObject lazymanifestType; /* If the manifest has changes, build the new manifest text and reindex it. */ static int compact(lazymanifest *self) { int i; ssize_t need = 0; char *data; line *src, *dst; PyObject *pydata; if (!self->dirty) return 0; for (i = 0; i < self->numlines; i++) { if (!self->lines[i].deleted) { need += self->lines[i].len; } } pydata = PyString_FromStringAndSize(NULL, need); if (!pydata) return -1; data = PyString_AsString(pydata); if (!data) { return -1; } src = self->lines; dst = self->lines; for (i = 0; i < self->numlines; i++, src++) { char *tofree = NULL; if (src->from_malloc) { tofree = src->start; } if (!src->deleted) { memcpy(data, src->start, src->len); *dst = *src; dst->start = data; dst->from_malloc = false; data += dst->len; dst++; } free(tofree); } Py_DECREF(self->pydata); self->pydata = pydata; self->numlines = self->livelines; self->dirty = false; return 0; } static PyObject *lazymanifest_text(lazymanifest *self) { if (compact(self) != 0) { PyErr_NoMemory(); return NULL; } Py_INCREF(self->pydata); return self->pydata; } static lazymanifest *lazymanifest_copy(lazymanifest *self) { lazymanifest *copy = NULL; if (compact(self) != 0) { goto nomem; } copy = PyObject_New(lazymanifest, &lazymanifestType); if (!copy) { goto nomem; } copy->numlines = self->numlines; copy->livelines = self->livelines; copy->dirty = false; copy->lines = malloc(self->maxlines *sizeof(line)); if (!copy->lines) { goto nomem; } memcpy(copy->lines, self->lines, self->numlines * sizeof(line)); copy->maxlines = self->maxlines; copy->pydata = self->pydata; Py_INCREF(copy->pydata); return copy; nomem: PyErr_NoMemory(); Py_XDECREF(copy); return NULL; } static lazymanifest *lazymanifest_filtercopy( lazymanifest *self, PyObject *matchfn) { lazymanifest *copy = NULL; int i; if (!PyCallable_Check(matchfn)) { PyErr_SetString(PyExc_TypeError, "matchfn must be callable"); return NULL; } /* compact ourselves first to avoid double-frees later when we * compact tmp so that it doesn't have random pointers to our * underlying from_malloc-data (self->pydata is safe) */ if (compact(self) != 0) { goto nomem; } copy = PyObject_New(lazymanifest, &lazymanifestType); copy->dirty = true; copy->lines = malloc(self->maxlines * sizeof(line)); if (!copy->lines) { goto nomem; } copy->maxlines = self->maxlines; copy->numlines = 0; copy->pydata = self->pydata; Py_INCREF(self->pydata); for (i = 0; i < self->numlines; i++) { PyObject *arg = PyString_FromString(self->lines[i].start); PyObject *arglist = PyTuple_Pack(1, arg); PyObject *result = PyObject_CallObject(matchfn, arglist); Py_DECREF(arglist); Py_DECREF(arg); /* if the callback raised an exception, just let it * through and give up */ if (!result) { free(copy->lines); Py_DECREF(self->pydata); return NULL; } if (PyObject_IsTrue(result)) { assert(!(self->lines[i].from_malloc)); copy->lines[copy->numlines++] = self->lines[i]; } Py_DECREF(result); } copy->livelines = copy->numlines; return copy; nomem: PyErr_NoMemory(); Py_XDECREF(copy); return NULL; } static PyObject *lazymanifest_diff(lazymanifest *self, PyObject *args) { lazymanifest *other; PyObject *pyclean = NULL; bool listclean; PyObject *emptyTup = NULL, *ret = NULL; PyObject *es; int sneedle = 0, oneedle = 0; if (!PyArg_ParseTuple(args, "O!|O", &lazymanifestType, &other, &pyclean)) { return NULL; } listclean = (!pyclean) ? false : PyObject_IsTrue(pyclean); es = PyString_FromString(""); if (!es) { goto nomem; } emptyTup = PyTuple_Pack(2, Py_None, es); Py_DECREF(es); if (!emptyTup) { goto nomem; } ret = PyDict_New(); if (!ret) { goto nomem; } while (sneedle != self->numlines || oneedle != other->numlines) { line *left = self->lines + sneedle; line *right = other->lines + oneedle; int result; PyObject *key; PyObject *outer; /* If we're looking at a deleted entry and it's not * the end of the manifest, just skip it. */ if (left->deleted && sneedle < self->numlines) { sneedle++; continue; } if (right->deleted && oneedle < other->numlines) { oneedle++; continue; } /* if we're at the end of either manifest, then we * know the remaining items are adds so we can skip * the strcmp. */ if (sneedle == self->numlines) { result = 1; } else if (oneedle == other->numlines) { result = -1; } else { result = linecmp(left, right); } key = result <= 0 ? PyString_FromString(left->start) : PyString_FromString(right->start); if (!key) goto nomem; if (result < 0) { PyObject *l = hashflags(left); if (!l) { goto nomem; } outer = PyTuple_Pack(2, l, emptyTup); Py_DECREF(l); if (!outer) { goto nomem; } PyDict_SetItem(ret, key, outer); Py_DECREF(outer); sneedle++; } else if (result > 0) { PyObject *r = hashflags(right); if (!r) { goto nomem; } outer = PyTuple_Pack(2, emptyTup, r); Py_DECREF(r); if (!outer) { goto nomem; } PyDict_SetItem(ret, key, outer); Py_DECREF(outer); oneedle++; } else { /* file exists in both manifests */ if (left->len != right->len || memcmp(left->start, right->start, left->len) || left->hash_suffix != right->hash_suffix) { PyObject *l = hashflags(left); PyObject *r; if (!l) { goto nomem; } r = hashflags(right); if (!r) { Py_DECREF(l); goto nomem; } outer = PyTuple_Pack(2, l, r); Py_DECREF(l); Py_DECREF(r); if (!outer) { goto nomem; } PyDict_SetItem(ret, key, outer); Py_DECREF(outer); } else if (listclean) { PyDict_SetItem(ret, key, Py_None); } sneedle++; oneedle++; } Py_DECREF(key); } Py_DECREF(emptyTup); return ret; nomem: PyErr_NoMemory(); Py_XDECREF(ret); Py_XDECREF(emptyTup); return NULL; } static PyMethodDef lazymanifest_methods[] = { {"iterkeys", (PyCFunction)lazymanifest_getkeysiter, METH_NOARGS, "Iterate over file names in this lazymanifest."}, {"iterentries", (PyCFunction)lazymanifest_getentriesiter, METH_NOARGS, "Iterate over (path, nodeid, flags) typles in this lazymanifest."}, {"copy", (PyCFunction)lazymanifest_copy, METH_NOARGS, "Make a copy of this lazymanifest."}, {"filtercopy", (PyCFunction)lazymanifest_filtercopy, METH_O, "Make a copy of this manifest filtered by matchfn."}, {"diff", (PyCFunction)lazymanifest_diff, METH_VARARGS, "Compare this lazymanifest to another one."}, {"text", (PyCFunction)lazymanifest_text, METH_NOARGS, "Encode this manifest to text."}, {NULL}, }; static PyTypeObject lazymanifestType = { PyObject_HEAD_INIT(NULL) 0, /* ob_size */ "parsers.lazymanifest", /* tp_name */ sizeof(lazymanifest), /* tp_basicsize */ 0, /* tp_itemsize */ (destructor)lazymanifest_dealloc, /* tp_dealloc */ 0, /* tp_print */ 0, /* tp_getattr */ 0, /* tp_setattr */ 0, /* tp_compare */ 0, /* tp_repr */ 0, /* tp_as_number */ &lazymanifest_seq_meths, /* tp_as_sequence */ &lazymanifest_mapping_methods, /* tp_as_mapping */ 0, /* tp_hash */ 0, /* tp_call */ 0, /* tp_str */ 0, /* tp_getattro */ 0, /* tp_setattro */ 0, /* tp_as_buffer */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_SEQUENCE_IN, /* tp_flags */ "TODO(augie)", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ 0, /* tp_richcompare */ 0, /* tp_weaklistoffset */ (getiterfunc)lazymanifest_getkeysiter, /* tp_iter */ 0, /* tp_iternext */ lazymanifest_methods, /* tp_methods */ 0, /* tp_members */ 0, /* tp_getset */ 0, /* tp_base */ 0, /* tp_dict */ 0, /* tp_descr_get */ 0, /* tp_descr_set */ 0, /* tp_dictoffset */ (initproc)lazymanifest_init, /* tp_init */ 0, /* tp_alloc */ }; void manifest_module_init(PyObject * mod) { lazymanifestType.tp_new = PyType_GenericNew; if (PyType_Ready(&lazymanifestType) < 0) return; Py_INCREF(&lazymanifestType); PyModule_AddObject(mod, "lazymanifest", (PyObject *)&lazymanifestType); }