mercurial/cext/parsers.c

phases: large rewrite on retract boundary

The new code is still pure Python, so we still have room to going significantly
faster. However its complexity of the complex part is `O(|[min_new_draft, tip]|)` instead of
`O(|[min_draft, tip]|` which should help tremendously one repository with old
draft (like mercurial-devel or mozilla-try).

This is especially useful as the most common "retract boundary" operation
happens when we commit/rewrite new drafts or when we push new draft to a
non-publishing server. In this case, the smallest new_revs is very close to the
tip and there is very few work to do.

A few smaller optimisation could be done for these cases and will be introduced in
later changesets.

We still have iterate over large sets of roots, but this is already a great
improvement for a very small amount of work. We gather information on the
affected changeset as we go as we can put it to use in the next changesets.
This extra data collection might slowdown the `register_new` case a bit, however
for register_new, it should not really matters. The set of new nodes is either
small, so the impact is negligible, or the set of new nodes is large, and the
amount of work to do to had them will dominate the overhead the collecting
information in `changed_revs`.

As this new code compute the changes on the fly, it unlock other interesting
improvement to be done in later changeset.

/*
 parsers.c - efficient content parsing

 Copyright 2008 Olivia Mackall <[e-mail]> and others

 This software may be used and distributed according to the terms of
 the GNU General Public License, incorporated herein by reference.
*/

#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <ctype.h>
#include <stddef.h>
#include <string.h>

#include "bitmanipulation.h"
#include "charencode.h"
#include "util.h"

static const char *const versionerrortext = "Python minor version mismatch";

static const int dirstate_v1_from_p2 = -2;
static const int dirstate_v1_nonnormal = -1;
static const int ambiguous_time = -1;

static PyObject *dict_new_presized(PyObject *self, PyObject *args)
{
	Py_ssize_t expected_size;

	if (!PyArg_ParseTuple(args, "n:make_presized_dict", &expected_size)) {
		return NULL;
	}

	return _dict_new_presized(expected_size);
}

static PyObject *dirstate_item_new(PyTypeObject *subtype, PyObject *args,
                                   PyObject *kwds)
{
	/* We do all the initialization here and not a tp_init function because
	 * dirstate_item is immutable. */
	dirstateItemObject *t;
	int wc_tracked;
	int p1_tracked;
	int p2_info;
	int has_meaningful_data;
	int has_meaningful_mtime;
	int mtime_second_ambiguous;
	int mode;
	int size;
	int mtime_s;
	int mtime_ns;
	PyObject *parentfiledata;
	PyObject *mtime;
	PyObject *fallback_exec;
	PyObject *fallback_symlink;
	static char *keywords_name[] = {
	    "wc_tracked",          "p1_tracked",           "p2_info",
	    "has_meaningful_data", "has_meaningful_mtime", "parentfiledata",
	    "fallback_exec",       "fallback_symlink",     NULL,
	};
	wc_tracked = 0;
	p1_tracked = 0;
	p2_info = 0;
	has_meaningful_mtime = 1;
	has_meaningful_data = 1;
	mtime_second_ambiguous = 0;
	parentfiledata = Py_None;
	fallback_exec = Py_None;
	fallback_symlink = Py_None;
	if (!PyArg_ParseTupleAndKeywords(args, kwds, "|iiiiiOOO", keywords_name,
	                                 &wc_tracked, &p1_tracked, &p2_info,
	                                 &has_meaningful_data,
	                                 &has_meaningful_mtime, &parentfiledata,
	                                 &fallback_exec, &fallback_symlink)) {
		return NULL;
	}
	t = (dirstateItemObject *)subtype->tp_alloc(subtype, 1);
	if (!t) {
		return NULL;
	}

	t->flags = 0;
	if (wc_tracked) {
		t->flags |= dirstate_flag_wc_tracked;
	}
	if (p1_tracked) {
		t->flags |= dirstate_flag_p1_tracked;
	}
	if (p2_info) {
		t->flags |= dirstate_flag_p2_info;
	}

	if (fallback_exec != Py_None) {
		t->flags |= dirstate_flag_has_fallback_exec;
		if (PyObject_IsTrue(fallback_exec)) {
			t->flags |= dirstate_flag_fallback_exec;
		}
	}
	if (fallback_symlink != Py_None) {
		t->flags |= dirstate_flag_has_fallback_symlink;
		if (PyObject_IsTrue(fallback_symlink)) {
			t->flags |= dirstate_flag_fallback_symlink;
		}
	}

	if (parentfiledata != Py_None) {
		if (!PyArg_ParseTuple(parentfiledata, "iiO", &mode, &size,
		                      &mtime)) {
			return NULL;
		}
		if (mtime != Py_None) {
			if (!PyArg_ParseTuple(mtime, "iii", &mtime_s, &mtime_ns,
			                      &mtime_second_ambiguous)) {
				return NULL;
			}
		} else {
			has_meaningful_mtime = 0;
		}
	} else {
		has_meaningful_data = 0;
		has_meaningful_mtime = 0;
	}
	if (has_meaningful_data) {
		t->flags |= dirstate_flag_has_meaningful_data;
		t->mode = mode;
		t->size = size;
		if (mtime_second_ambiguous) {
			t->flags |= dirstate_flag_mtime_second_ambiguous;
		}
	} else {
		t->mode = 0;
		t->size = 0;
	}
	if (has_meaningful_mtime) {
		t->flags |= dirstate_flag_has_mtime;
		t->mtime_s = mtime_s;
		t->mtime_ns = mtime_ns;
	} else {
		t->mtime_s = 0;
		t->mtime_ns = 0;
	}
	return (PyObject *)t;
}

static void dirstate_item_dealloc(PyObject *o)
{
	PyObject_Del(o);
}

static inline bool dirstate_item_c_tracked(dirstateItemObject *self)
{
	return (self->flags & dirstate_flag_wc_tracked);
}

static inline bool dirstate_item_c_any_tracked(dirstateItemObject *self)
{
	const int mask = dirstate_flag_wc_tracked | dirstate_flag_p1_tracked |
	                 dirstate_flag_p2_info;
	return (self->flags & mask);
}

static inline bool dirstate_item_c_added(dirstateItemObject *self)
{
	const int mask = (dirstate_flag_wc_tracked | dirstate_flag_p1_tracked |
	                  dirstate_flag_p2_info);
	const int target = dirstate_flag_wc_tracked;
	return (self->flags & mask) == target;
}

static inline bool dirstate_item_c_removed(dirstateItemObject *self)
{
	if (self->flags & dirstate_flag_wc_tracked) {
		return false;
	}
	return (self->flags &
	        (dirstate_flag_p1_tracked | dirstate_flag_p2_info));
}

static inline bool dirstate_item_c_modified(dirstateItemObject *self)
{
	return ((self->flags & dirstate_flag_wc_tracked) &&
	        (self->flags & dirstate_flag_p1_tracked) &&
	        (self->flags & dirstate_flag_p2_info));
}

static inline bool dirstate_item_c_from_p2(dirstateItemObject *self)
{
	return ((self->flags & dirstate_flag_wc_tracked) &&
	        !(self->flags & dirstate_flag_p1_tracked) &&
	        (self->flags & dirstate_flag_p2_info));
}

static inline char dirstate_item_c_v1_state(dirstateItemObject *self)
{
	if (dirstate_item_c_removed(self)) {
		return 'r';
	} else if (dirstate_item_c_modified(self)) {
		return 'm';
	} else if (dirstate_item_c_added(self)) {
		return 'a';
	} else {
		return 'n';
	}
}

static inline bool dirstate_item_c_has_fallback_exec(dirstateItemObject *self)
{
	return (bool)self->flags & dirstate_flag_has_fallback_exec;
}

static inline bool
dirstate_item_c_has_fallback_symlink(dirstateItemObject *self)
{
	return (bool)self->flags & dirstate_flag_has_fallback_symlink;
}

static inline int dirstate_item_c_v1_mode(dirstateItemObject *self)
{
	if (self->flags & dirstate_flag_has_meaningful_data) {
		return self->mode;
	} else {
		return 0;
	}
}

static inline int dirstate_item_c_v1_size(dirstateItemObject *self)
{
	if (!(self->flags & dirstate_flag_wc_tracked) &&
	    (self->flags & dirstate_flag_p2_info)) {
		if (self->flags & dirstate_flag_p1_tracked) {
			return dirstate_v1_nonnormal;
		} else {
			return dirstate_v1_from_p2;
		}
	} else if (dirstate_item_c_removed(self)) {
		return 0;
	} else if (self->flags & dirstate_flag_p2_info) {
		return dirstate_v1_from_p2;
	} else if (dirstate_item_c_added(self)) {
		return dirstate_v1_nonnormal;
	} else if (self->flags & dirstate_flag_has_meaningful_data) {
		return self->size;
	} else {
		return dirstate_v1_nonnormal;
	}
}

static inline int dirstate_item_c_v1_mtime(dirstateItemObject *self)
{
	if (dirstate_item_c_removed(self)) {
		return 0;
	} else if (!(self->flags & dirstate_flag_has_mtime) ||
	           !(self->flags & dirstate_flag_p1_tracked) ||
	           !(self->flags & dirstate_flag_wc_tracked) ||
	           (self->flags & dirstate_flag_p2_info) ||
	           (self->flags & dirstate_flag_mtime_second_ambiguous)) {
		return ambiguous_time;
	} else {
		return self->mtime_s;
	}
}

static PyObject *dirstate_item_v2_data(dirstateItemObject *self)
{
	int flags = self->flags;
	int mode = dirstate_item_c_v1_mode(self);
#ifdef S_IXUSR
	/* This is for platforms with an exec bit */
	if ((mode & S_IXUSR) != 0) {
		flags |= dirstate_flag_mode_exec_perm;
	} else {
		flags &= ~dirstate_flag_mode_exec_perm;
	}
#else
	flags &= ~dirstate_flag_mode_exec_perm;
#endif
#ifdef S_ISLNK
	/* This is for platforms with support for symlinks */
	if (S_ISLNK(mode)) {
		flags |= dirstate_flag_mode_is_symlink;
	} else {
		flags &= ~dirstate_flag_mode_is_symlink;
	}
#else
	flags &= ~dirstate_flag_mode_is_symlink;
#endif
	return Py_BuildValue("iiii", flags, self->size, self->mtime_s,
	                     self->mtime_ns);
};

static PyObject *dirstate_item_mtime_likely_equal_to(dirstateItemObject *self,
                                                     PyObject *other)
{
	int other_s;
	int other_ns;
	int other_second_ambiguous;
	if (!PyArg_ParseTuple(other, "iii", &other_s, &other_ns,
	                      &other_second_ambiguous)) {
		return NULL;
	}
	if (!(self->flags & dirstate_flag_has_mtime)) {
		Py_RETURN_FALSE;
	}
	if (self->mtime_s != other_s) {
		Py_RETURN_FALSE;
	}
	if (self->mtime_ns == 0 || other_ns == 0) {
		if (self->flags & dirstate_flag_mtime_second_ambiguous) {
			Py_RETURN_FALSE;
		} else {
			Py_RETURN_TRUE;
		}
	}
	if (self->mtime_ns == other_ns) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

/* This will never change since it's bound to V1
 */
static inline dirstateItemObject *
dirstate_item_from_v1_data(char state, int mode, int size, int mtime)
{
	dirstateItemObject *t =
	    PyObject_New(dirstateItemObject, &dirstateItemType);
	if (!t) {
		return NULL;
	}
	t->flags = 0;
	t->mode = 0;
	t->size = 0;
	t->mtime_s = 0;
	t->mtime_ns = 0;

	if (state == 'm') {
		t->flags = (dirstate_flag_wc_tracked |
		            dirstate_flag_p1_tracked | dirstate_flag_p2_info);
	} else if (state == 'a') {
		t->flags = dirstate_flag_wc_tracked;
	} else if (state == 'r') {
		if (size == dirstate_v1_nonnormal) {
			t->flags =
			    dirstate_flag_p1_tracked | dirstate_flag_p2_info;
		} else if (size == dirstate_v1_from_p2) {
			t->flags = dirstate_flag_p2_info;
		} else {
			t->flags = dirstate_flag_p1_tracked;
		}
	} else if (state == 'n') {
		if (size == dirstate_v1_from_p2) {
			t->flags =
			    dirstate_flag_wc_tracked | dirstate_flag_p2_info;
		} else if (size == dirstate_v1_nonnormal) {
			t->flags =
			    dirstate_flag_wc_tracked | dirstate_flag_p1_tracked;
		} else if (mtime == ambiguous_time) {
			t->flags = (dirstate_flag_wc_tracked |
			            dirstate_flag_p1_tracked |
			            dirstate_flag_has_meaningful_data);
			t->mode = mode;
			t->size = size;
		} else {
			t->flags = (dirstate_flag_wc_tracked |
			            dirstate_flag_p1_tracked |
			            dirstate_flag_has_meaningful_data |
			            dirstate_flag_has_mtime);
			t->mode = mode;
			t->size = size;
			t->mtime_s = mtime;
		}
	} else {
		PyErr_Format(PyExc_RuntimeError,
		             "unknown state: `%c` (%d, %d, %d)", state, mode,
		             size, mtime);
		Py_DECREF(t);
		return NULL;
	}

	return t;
}

static PyObject *dirstate_item_from_v2_meth(PyTypeObject *subtype,
                                            PyObject *args)
{
	dirstateItemObject *t =
	    PyObject_New(dirstateItemObject, &dirstateItemType);
	if (!t) {
		return NULL;
	}
	if (!PyArg_ParseTuple(args, "iiii", &t->flags, &t->size, &t->mtime_s,
	                      &t->mtime_ns)) {
		return NULL;
	}
	if (t->flags & dirstate_flag_expected_state_is_modified) {
		t->flags &= ~(dirstate_flag_expected_state_is_modified |
		              dirstate_flag_has_meaningful_data |
		              dirstate_flag_has_mtime);
	}
	t->mode = 0;
	if (t->flags & dirstate_flag_has_meaningful_data) {
		if (t->flags & dirstate_flag_mode_exec_perm) {
			t->mode = 0755;
		} else {
			t->mode = 0644;
		}
		if (t->flags & dirstate_flag_mode_is_symlink) {
			t->mode |= S_IFLNK;
		} else {
			t->mode |= S_IFREG;
		}
	}
	return (PyObject *)t;
};

/* This means the next status call will have to actually check its content
   to make sure it is correct. */
static PyObject *dirstate_item_set_possibly_dirty(dirstateItemObject *self)
{
	self->flags &= ~dirstate_flag_has_mtime;
	Py_RETURN_NONE;
}

/* See docstring of the python implementation for details */
static PyObject *dirstate_item_set_clean(dirstateItemObject *self,
                                         PyObject *args)
{
	int size, mode, mtime_s, mtime_ns, mtime_second_ambiguous;
	PyObject *mtime;
	mtime_s = 0;
	mtime_ns = 0;
	mtime_second_ambiguous = 0;
	if (!PyArg_ParseTuple(args, "iiO", &mode, &size, &mtime)) {
		return NULL;
	}
	if (mtime != Py_None) {
		if (!PyArg_ParseTuple(mtime, "iii", &mtime_s, &mtime_ns,
		                      &mtime_second_ambiguous)) {
			return NULL;
		}
	} else {
		self->flags &= ~dirstate_flag_has_mtime;
	}
	self->flags = dirstate_flag_wc_tracked | dirstate_flag_p1_tracked |
	              dirstate_flag_has_meaningful_data |
	              dirstate_flag_has_mtime;
	if (mtime_second_ambiguous) {
		self->flags |= dirstate_flag_mtime_second_ambiguous;
	}
	self->mode = mode;
	self->size = size;
	self->mtime_s = mtime_s;
	self->mtime_ns = mtime_ns;
	Py_RETURN_NONE;
}

static PyObject *dirstate_item_set_tracked(dirstateItemObject *self)
{
	self->flags |= dirstate_flag_wc_tracked;
	self->flags &= ~dirstate_flag_has_mtime;
	Py_RETURN_NONE;
}

static PyObject *dirstate_item_set_untracked(dirstateItemObject *self)
{
	self->flags &= ~dirstate_flag_wc_tracked;
	self->flags &= ~dirstate_flag_has_meaningful_data;
	self->flags &= ~dirstate_flag_has_mtime;
	self->mode = 0;
	self->size = 0;
	self->mtime_s = 0;
	self->mtime_ns = 0;
	Py_RETURN_NONE;
}

static PyObject *dirstate_item_drop_merge_data(dirstateItemObject *self)
{
	if (self->flags & dirstate_flag_p2_info) {
		self->flags &= ~(dirstate_flag_p2_info |
		                 dirstate_flag_has_meaningful_data |
		                 dirstate_flag_has_mtime);
		self->mode = 0;
		self->size = 0;
		self->mtime_s = 0;
		self->mtime_ns = 0;
	}
	Py_RETURN_NONE;
}
static PyMethodDef dirstate_item_methods[] = {
    {"v2_data", (PyCFunction)dirstate_item_v2_data, METH_NOARGS,
     "return data suitable for v2 serialization"},
    {"mtime_likely_equal_to", (PyCFunction)dirstate_item_mtime_likely_equal_to,
     METH_O, "True if the stored mtime is likely equal to the given mtime"},
    {"from_v2_data", (PyCFunction)dirstate_item_from_v2_meth,
     METH_VARARGS | METH_CLASS, "build a new DirstateItem object from V2 data"},
    {"set_possibly_dirty", (PyCFunction)dirstate_item_set_possibly_dirty,
     METH_NOARGS, "mark a file as \"possibly dirty\""},
    {"set_clean", (PyCFunction)dirstate_item_set_clean, METH_VARARGS,
     "mark a file as \"clean\""},
    {"set_tracked", (PyCFunction)dirstate_item_set_tracked, METH_NOARGS,
     "mark a file as \"tracked\""},
    {"set_untracked", (PyCFunction)dirstate_item_set_untracked, METH_NOARGS,
     "mark a file as \"untracked\""},
    {"drop_merge_data", (PyCFunction)dirstate_item_drop_merge_data, METH_NOARGS,
     "remove all \"merge-only\" from a DirstateItem"},
    {NULL} /* Sentinel */
};

static PyObject *dirstate_item_get_mode(dirstateItemObject *self)
{
	return PyLong_FromLong(dirstate_item_c_v1_mode(self));
};

static PyObject *dirstate_item_get_size(dirstateItemObject *self)
{
	return PyLong_FromLong(dirstate_item_c_v1_size(self));
};

static PyObject *dirstate_item_get_mtime(dirstateItemObject *self)
{
	return PyLong_FromLong(dirstate_item_c_v1_mtime(self));
};

static PyObject *dirstate_item_get_state(dirstateItemObject *self)
{
	char state = dirstate_item_c_v1_state(self);
	return PyBytes_FromStringAndSize(&state, 1);
};

static PyObject *dirstate_item_get_has_fallback_exec(dirstateItemObject *self)
{
	if (dirstate_item_c_has_fallback_exec(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_fallback_exec(dirstateItemObject *self)
{
	if (dirstate_item_c_has_fallback_exec(self)) {
		if (self->flags & dirstate_flag_fallback_exec) {
			Py_RETURN_TRUE;
		} else {
			Py_RETURN_FALSE;
		}
	} else {
		Py_RETURN_NONE;
	}
};

static int dirstate_item_set_fallback_exec(dirstateItemObject *self,
                                           PyObject *value)
{
	if ((value == Py_None) || (value == NULL)) {
		self->flags &= ~dirstate_flag_has_fallback_exec;
	} else {
		self->flags |= dirstate_flag_has_fallback_exec;
		if (PyObject_IsTrue(value)) {
			self->flags |= dirstate_flag_fallback_exec;
		} else {
			self->flags &= ~dirstate_flag_fallback_exec;
		}
	}
	return 0;
};

static PyObject *
dirstate_item_get_has_fallback_symlink(dirstateItemObject *self)
{
	if (dirstate_item_c_has_fallback_symlink(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_fallback_symlink(dirstateItemObject *self)
{
	if (dirstate_item_c_has_fallback_symlink(self)) {
		if (self->flags & dirstate_flag_fallback_symlink) {
			Py_RETURN_TRUE;
		} else {
			Py_RETURN_FALSE;
		}
	} else {
		Py_RETURN_NONE;
	}
};

static int dirstate_item_set_fallback_symlink(dirstateItemObject *self,
                                              PyObject *value)
{
	if ((value == Py_None) || (value == NULL)) {
		self->flags &= ~dirstate_flag_has_fallback_symlink;
	} else {
		self->flags |= dirstate_flag_has_fallback_symlink;
		if (PyObject_IsTrue(value)) {
			self->flags |= dirstate_flag_fallback_symlink;
		} else {
			self->flags &= ~dirstate_flag_fallback_symlink;
		}
	}
	return 0;
};

static PyObject *dirstate_item_get_tracked(dirstateItemObject *self)
{
	if (dirstate_item_c_tracked(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};
static PyObject *dirstate_item_get_p1_tracked(dirstateItemObject *self)
{
	if (self->flags & dirstate_flag_p1_tracked) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_added(dirstateItemObject *self)
{
	if (dirstate_item_c_added(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_p2_info(dirstateItemObject *self)
{
	if (self->flags & dirstate_flag_wc_tracked &&
	    self->flags & dirstate_flag_p2_info) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_modified(dirstateItemObject *self)
{
	if (dirstate_item_c_modified(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_from_p2(dirstateItemObject *self)
{
	if (dirstate_item_c_from_p2(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_maybe_clean(dirstateItemObject *self)
{
	if (!(self->flags & dirstate_flag_wc_tracked)) {
		Py_RETURN_FALSE;
	} else if (!(self->flags & dirstate_flag_p1_tracked)) {
		Py_RETURN_FALSE;
	} else if (self->flags & dirstate_flag_p2_info) {
		Py_RETURN_FALSE;
	} else {
		Py_RETURN_TRUE;
	}
};

static PyObject *dirstate_item_get_any_tracked(dirstateItemObject *self)
{
	if (dirstate_item_c_any_tracked(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyObject *dirstate_item_get_removed(dirstateItemObject *self)
{
	if (dirstate_item_c_removed(self)) {
		Py_RETURN_TRUE;
	} else {
		Py_RETURN_FALSE;
	}
};

static PyGetSetDef dirstate_item_getset[] = {
    {"mode", (getter)dirstate_item_get_mode, NULL, "mode", NULL},
    {"size", (getter)dirstate_item_get_size, NULL, "size", NULL},
    {"mtime", (getter)dirstate_item_get_mtime, NULL, "mtime", NULL},
    {"state", (getter)dirstate_item_get_state, NULL, "state", NULL},
    {"has_fallback_exec", (getter)dirstate_item_get_has_fallback_exec, NULL,
     "has_fallback_exec", NULL},
    {"fallback_exec", (getter)dirstate_item_get_fallback_exec,
     (setter)dirstate_item_set_fallback_exec, "fallback_exec", NULL},
    {"has_fallback_symlink", (getter)dirstate_item_get_has_fallback_symlink,
     NULL, "has_fallback_symlink", NULL},
    {"fallback_symlink", (getter)dirstate_item_get_fallback_symlink,
     (setter)dirstate_item_set_fallback_symlink, "fallback_symlink", NULL},
    {"tracked", (getter)dirstate_item_get_tracked, NULL, "tracked", NULL},
    {"p1_tracked", (getter)dirstate_item_get_p1_tracked, NULL, "p1_tracked",
     NULL},
    {"added", (getter)dirstate_item_get_added, NULL, "added", NULL},
    {"p2_info", (getter)dirstate_item_get_p2_info, NULL, "p2_info", NULL},
    {"modified", (getter)dirstate_item_get_modified, NULL, "modified", NULL},
    {"from_p2", (getter)dirstate_item_get_from_p2, NULL, "from_p2", NULL},
    {"maybe_clean", (getter)dirstate_item_get_maybe_clean, NULL, "maybe_clean",
     NULL},
    {"any_tracked", (getter)dirstate_item_get_any_tracked, NULL, "any_tracked",
     NULL},
    {"removed", (getter)dirstate_item_get_removed, NULL, "removed", NULL},
    {NULL} /* Sentinel */
};

PyTypeObject dirstateItemType = {
    PyVarObject_HEAD_INIT(NULL, 0)     /* header */
    "dirstate_tuple",                  /* tp_name */
    sizeof(dirstateItemObject),        /* tp_basicsize */
    0,                                 /* tp_itemsize */
    (destructor)dirstate_item_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 */
    Py_TPFLAGS_DEFAULT,                /* tp_flags */
    "dirstate tuple",                  /* tp_doc */
    0,                                 /* tp_traverse */
    0,                                 /* tp_clear */
    0,                                 /* tp_richcompare */
    0,                                 /* tp_weaklistoffset */
    0,                                 /* tp_iter */
    0,                                 /* tp_iternext */
    dirstate_item_methods,             /* tp_methods */
    0,                                 /* tp_members */
    dirstate_item_getset,              /* tp_getset */
    0,                                 /* tp_base */
    0,                                 /* tp_dict */
    0,                                 /* tp_descr_get */
    0,                                 /* tp_descr_set */
    0,                                 /* tp_dictoffset */
    0,                                 /* tp_init */
    0,                                 /* tp_alloc */
    dirstate_item_new,                 /* tp_new */
};

static PyObject *parse_dirstate(PyObject *self, PyObject *args)
{
	PyObject *dmap, *cmap, *parents = NULL, *ret = NULL;
	PyObject *fname = NULL, *cname = NULL, *entry = NULL;
	char state, *cur, *str, *cpos;
	int mode, size, mtime;
	unsigned int flen, pos = 40;
	Py_ssize_t len = 40;
	Py_ssize_t readlen;

	if (!PyArg_ParseTuple(args, "O!O!y#:parse_dirstate", &PyDict_Type,
	                      &dmap, &PyDict_Type, &cmap, &str, &readlen)) {
		goto quit;
	}

	len = readlen;

	/* read parents */
	if (len < 40) {
		PyErr_SetString(PyExc_ValueError,
		                "too little data for parents");
		goto quit;
	}

	parents = Py_BuildValue("y#y#", str, (Py_ssize_t)20, str + 20,
	                        (Py_ssize_t)20);
	if (!parents) {
		goto quit;
	}

	/* read filenames */
	while (pos >= 40 && pos < len) {
		if (pos + 17 > len) {
			PyErr_SetString(PyExc_ValueError,
			                "overflow in dirstate");
			goto quit;
		}
		cur = str + pos;
		/* unpack header */
		state = *cur;
		mode = getbe32(cur + 1);
		size = getbe32(cur + 5);
		mtime = getbe32(cur + 9);
		flen = getbe32(cur + 13);
		pos += 17;
		cur += 17;
		if (flen > len - pos) {
			PyErr_SetString(PyExc_ValueError,
			                "overflow in dirstate");
			goto quit;
		}

		entry = (PyObject *)dirstate_item_from_v1_data(state, mode,
		                                               size, mtime);
		if (!entry)
			goto quit;
		cpos = memchr(cur, 0, flen);
		if (cpos) {
			fname = PyBytes_FromStringAndSize(cur, cpos - cur);
			cname = PyBytes_FromStringAndSize(
			    cpos + 1, flen - (cpos - cur) - 1);
			if (!fname || !cname ||
			    PyDict_SetItem(cmap, fname, cname) == -1 ||
			    PyDict_SetItem(dmap, fname, entry) == -1) {
				goto quit;
			}
			Py_DECREF(cname);
		} else {
			fname = PyBytes_FromStringAndSize(cur, flen);
			if (!fname ||
			    PyDict_SetItem(dmap, fname, entry) == -1) {
				goto quit;
			}
		}
		Py_DECREF(fname);
		Py_DECREF(entry);
		fname = cname = entry = NULL;
		pos += flen;
	}

	ret = parents;
	Py_INCREF(ret);
quit:
	Py_XDECREF(fname);
	Py_XDECREF(cname);
	Py_XDECREF(entry);
	Py_XDECREF(parents);
	return ret;
}

/*
 * Efficiently pack a dirstate object into its on-disk format.
 */
static PyObject *pack_dirstate(PyObject *self, PyObject *args)
{
	PyObject *packobj = NULL;
	PyObject *map, *copymap, *pl, *mtime_unset = NULL;
	Py_ssize_t nbytes, pos, l;
	PyObject *k, *v = NULL, *pn;
	char *p, *s;

	if (!PyArg_ParseTuple(args, "O!O!O!:pack_dirstate", &PyDict_Type, &map,
	                      &PyDict_Type, &copymap, &PyTuple_Type, &pl)) {
		return NULL;
	}

	if (PyTuple_Size(pl) != 2) {
		PyErr_SetString(PyExc_TypeError, "expected 2-element tuple");
		return NULL;
	}

	/* Figure out how much we need to allocate. */
	for (nbytes = 40, pos = 0; PyDict_Next(map, &pos, &k, &v);) {
		PyObject *c;
		if (!PyBytes_Check(k)) {
			PyErr_SetString(PyExc_TypeError, "expected string key");
			goto bail;
		}
		nbytes += PyBytes_GET_SIZE(k) + 17;
		c = PyDict_GetItem(copymap, k);
		if (c) {
			if (!PyBytes_Check(c)) {
				PyErr_SetString(PyExc_TypeError,
				                "expected string key");
				goto bail;
			}
			nbytes += PyBytes_GET_SIZE(c) + 1;
		}
	}

	packobj = PyBytes_FromStringAndSize(NULL, nbytes);
	if (packobj == NULL) {
		goto bail;
	}

	p = PyBytes_AS_STRING(packobj);

	pn = PyTuple_GET_ITEM(pl, 0);
	if (PyBytes_AsStringAndSize(pn, &s, &l) == -1 || l != 20) {
		PyErr_SetString(PyExc_TypeError, "expected a 20-byte hash");
		goto bail;
	}
	memcpy(p, s, l);
	p += 20;
	pn = PyTuple_GET_ITEM(pl, 1);
	if (PyBytes_AsStringAndSize(pn, &s, &l) == -1 || l != 20) {
		PyErr_SetString(PyExc_TypeError, "expected a 20-byte hash");
		goto bail;
	}
	memcpy(p, s, l);
	p += 20;

	for (pos = 0; PyDict_Next(map, &pos, &k, &v);) {
		dirstateItemObject *tuple;
		char state;
		int mode, size, mtime;
		Py_ssize_t len, l;
		PyObject *o;
		char *t;

		if (!dirstate_tuple_check(v)) {
			PyErr_SetString(PyExc_TypeError,
			                "expected a dirstate tuple");
			goto bail;
		}
		tuple = (dirstateItemObject *)v;

		state = dirstate_item_c_v1_state(tuple);
		mode = dirstate_item_c_v1_mode(tuple);
		size = dirstate_item_c_v1_size(tuple);
		mtime = dirstate_item_c_v1_mtime(tuple);
		*p++ = state;
		putbe32((uint32_t)mode, p);
		putbe32((uint32_t)size, p + 4);
		putbe32((uint32_t)mtime, p + 8);
		t = p + 12;
		p += 16;
		len = PyBytes_GET_SIZE(k);
		memcpy(p, PyBytes_AS_STRING(k), len);
		p += len;
		o = PyDict_GetItem(copymap, k);
		if (o) {
			*p++ = '\0';
			l = PyBytes_GET_SIZE(o);
			memcpy(p, PyBytes_AS_STRING(o), l);
			p += l;
			len += l + 1;
		}
		putbe32((uint32_t)len, t);
	}

	pos = p - PyBytes_AS_STRING(packobj);
	if (pos != nbytes) {
		PyErr_Format(PyExc_SystemError, "bad dirstate size: %ld != %ld",
		             (long)pos, (long)nbytes);
		goto bail;
	}

	return packobj;
bail:
	Py_XDECREF(mtime_unset);
	Py_XDECREF(packobj);
	Py_XDECREF(v);
	return NULL;
}

#define BUMPED_FIX 1
#define USING_SHA_256 2
#define FM1_HEADER_SIZE (4 + 8 + 2 + 2 + 1 + 1 + 1)

static PyObject *readshas(const char *source, unsigned char num,
                          Py_ssize_t hashwidth)
{
	int i;
	PyObject *list = PyTuple_New(num);
	if (list == NULL) {
		return NULL;
	}
	for (i = 0; i < num; i++) {
		PyObject *hash = PyBytes_FromStringAndSize(source, hashwidth);
		if (hash == NULL) {
			Py_DECREF(list);
			return NULL;
		}
		PyTuple_SET_ITEM(list, i, hash);
		source += hashwidth;
	}
	return list;
}

static PyObject *fm1readmarker(const char *databegin, const char *dataend,
                               uint32_t *msize)
{
	const char *data = databegin;
	const char *meta;

	double mtime;
	int16_t tz;
	uint16_t flags;
	unsigned char nsuccs, nparents, nmetadata;
	Py_ssize_t hashwidth = 20;

	PyObject *prec = NULL, *parents = NULL, *succs = NULL;
	PyObject *metadata = NULL, *ret = NULL;
	int i;

	if (data + FM1_HEADER_SIZE > dataend) {
		goto overflow;
	}

	*msize = getbe32(data);
	data += 4;
	mtime = getbefloat64(data);
	data += 8;
	tz = getbeint16(data);
	data += 2;
	flags = getbeuint16(data);
	data += 2;

	if (flags & USING_SHA_256) {
		hashwidth = 32;
	}

	nsuccs = (unsigned char)(*data++);
	nparents = (unsigned char)(*data++);
	nmetadata = (unsigned char)(*data++);

	if (databegin + *msize > dataend) {
		goto overflow;
	}
	dataend = databegin + *msize; /* narrow down to marker size */

	if (data + hashwidth > dataend) {
		goto overflow;
	}
	prec = PyBytes_FromStringAndSize(data, hashwidth);
	data += hashwidth;
	if (prec == NULL) {
		goto bail;
	}

	if (data + nsuccs * hashwidth > dataend) {
		goto overflow;
	}
	succs = readshas(data, nsuccs, hashwidth);
	if (succs == NULL) {
		goto bail;
	}
	data += nsuccs * hashwidth;

	if (nparents == 1 || nparents == 2) {
		if (data + nparents * hashwidth > dataend) {
			goto overflow;
		}
		parents = readshas(data, nparents, hashwidth);
		if (parents == NULL) {
			goto bail;
		}
		data += nparents * hashwidth;
	} else {
		parents = Py_None;
		Py_INCREF(parents);
	}

	if (data + 2 * nmetadata > dataend) {
		goto overflow;
	}
	meta = data + (2 * nmetadata);
	metadata = PyTuple_New(nmetadata);
	if (metadata == NULL) {
		goto bail;
	}
	for (i = 0; i < nmetadata; i++) {
		PyObject *tmp, *left = NULL, *right = NULL;
		Py_ssize_t leftsize = (unsigned char)(*data++);
		Py_ssize_t rightsize = (unsigned char)(*data++);
		if (meta + leftsize + rightsize > dataend) {
			goto overflow;
		}
		left = PyBytes_FromStringAndSize(meta, leftsize);
		meta += leftsize;
		right = PyBytes_FromStringAndSize(meta, rightsize);
		meta += rightsize;
		tmp = PyTuple_New(2);
		if (!left || !right || !tmp) {
			Py_XDECREF(left);
			Py_XDECREF(right);
			Py_XDECREF(tmp);
			goto bail;
		}
		PyTuple_SET_ITEM(tmp, 0, left);
		PyTuple_SET_ITEM(tmp, 1, right);
		PyTuple_SET_ITEM(metadata, i, tmp);
	}
	ret = Py_BuildValue("(OOHO(di)O)", prec, succs, flags, metadata, mtime,
	                    (int)tz * 60, parents);
	goto bail; /* return successfully */

overflow:
	PyErr_SetString(PyExc_ValueError, "overflow in obsstore");
bail:
	Py_XDECREF(prec);
	Py_XDECREF(succs);
	Py_XDECREF(metadata);
	Py_XDECREF(parents);
	return ret;
}

static PyObject *fm1readmarkers(PyObject *self, PyObject *args)
{
	const char *data, *dataend;
	Py_ssize_t datalen, offset, stop;
	PyObject *markers = NULL;

	if (!PyArg_ParseTuple(args, "y#nn", &data, &datalen, &offset, &stop)) {
		return NULL;
	}
	if (offset < 0) {
		PyErr_SetString(PyExc_ValueError,
		                "invalid negative offset in fm1readmarkers");
		return NULL;
	}
	if (stop > datalen) {
		PyErr_SetString(
		    PyExc_ValueError,
		    "stop longer than data length in fm1readmarkers");
		return NULL;
	}
	dataend = data + datalen;
	data += offset;
	markers = PyList_New(0);
	if (!markers) {
		return NULL;
	}
	while (offset < stop) {
		uint32_t msize;
		int error;
		PyObject *record = fm1readmarker(data, dataend, &msize);
		if (!record) {
			goto bail;
		}
		error = PyList_Append(markers, record);
		Py_DECREF(record);
		if (error) {
			goto bail;
		}
		data += msize;
		offset += msize;
	}
	return markers;
bail:
	Py_DECREF(markers);
	return NULL;
}

static char parsers_doc[] = "Efficient content parsing.";

PyObject *encodedir(PyObject *self, PyObject *args);
PyObject *pathencode(PyObject *self, PyObject *args);
PyObject *lowerencode(PyObject *self, PyObject *args);
PyObject *parse_index2(PyObject *self, PyObject *args, PyObject *kwargs);

static PyMethodDef methods[] = {
    {"pack_dirstate", pack_dirstate, METH_VARARGS, "pack a dirstate\n"},
    {"parse_dirstate", parse_dirstate, METH_VARARGS, "parse a dirstate\n"},
    {"parse_index2", (PyCFunction)parse_index2, METH_VARARGS | METH_KEYWORDS,
     "parse a revlog index\n"},
    {"isasciistr", isasciistr, METH_VARARGS, "check if an ASCII string\n"},
    {"asciilower", asciilower, METH_VARARGS, "lowercase an ASCII string\n"},
    {"asciiupper", asciiupper, METH_VARARGS, "uppercase an ASCII string\n"},
    {"dict_new_presized", dict_new_presized, METH_VARARGS,
     "construct a dict with an expected size\n"},
    {"make_file_foldmap", make_file_foldmap, METH_VARARGS,
     "make file foldmap\n"},
    {"jsonescapeu8fast", jsonescapeu8fast, METH_VARARGS,
     "escape a UTF-8 byte string to JSON (fast path)\n"},
    {"encodedir", encodedir, METH_VARARGS, "encodedir a path\n"},
    {"pathencode", pathencode, METH_VARARGS, "fncache-encode a path\n"},
    {"lowerencode", lowerencode, METH_VARARGS, "lower-encode a path\n"},
    {"fm1readmarkers", fm1readmarkers, METH_VARARGS,
     "parse v1 obsolete markers\n"},
    {NULL, NULL}};

void dirs_module_init(PyObject *mod);
void manifest_module_init(PyObject *mod);
void revlog_module_init(PyObject *mod);

static const int version = 21;

static void module_init(PyObject *mod)
{
	PyModule_AddIntConstant(mod, "version", version);

	/* This module constant has two purposes.  First, it lets us unit test
	 * the ImportError raised without hard-coding any error text.  This
	 * means we can change the text in the future without breaking tests,
	 * even across changesets without a recompile.  Second, its presence
	 * can be used to determine whether the version-checking logic is
	 * present, which also helps in testing across changesets without a
	 * recompile.  Note that this means the pure-Python version of parsers
	 * should not have this module constant. */
	PyModule_AddStringConstant(mod, "versionerrortext", versionerrortext);

	dirs_module_init(mod);
	manifest_module_init(mod);
	revlog_module_init(mod);

	if (PyType_Ready(&dirstateItemType) < 0) {
		return;
	}
	Py_INCREF(&dirstateItemType);
	PyModule_AddObject(mod, "DirstateItem", (PyObject *)&dirstateItemType);
}

static int check_python_version(void)
{
	PyObject *sys = PyImport_ImportModule("sys"), *ver;
	long hexversion;
	if (!sys) {
		return -1;
	}
	ver = PyObject_GetAttrString(sys, "hexversion");
	Py_DECREF(sys);
	if (!ver) {
		return -1;
	}
	hexversion = PyLong_AsLong(ver);
	Py_DECREF(ver);
	/* sys.hexversion is a 32-bit number by default, so the -1 case
	 * should only occur in unusual circumstances (e.g. if sys.hexversion
	 * is manually set to an invalid value). */
	if ((hexversion == -1) || (hexversion >> 16 != PY_VERSION_HEX >> 16)) {
		PyErr_Format(PyExc_ImportError,
		             "%s: The Mercurial extension "
		             "modules were compiled with Python " PY_VERSION
		             ", but "
		             "Mercurial is currently using Python with "
		             "sys.hexversion=%ld: "
		             "Python %s\n at: %s",
		             versionerrortext, hexversion, Py_GetVersion(),
		             Py_GetProgramFullPath());
		return -1;
	}
	return 0;
}

static struct PyModuleDef parsers_module = {PyModuleDef_HEAD_INIT, "parsers",
                                            parsers_doc, -1, methods};

PyMODINIT_FUNC PyInit_parsers(void)
{
	PyObject *mod;

	if (check_python_version() == -1)
		return NULL;
	mod = PyModule_Create(&parsers_module);
	module_init(mod);
	return mod;
}