# HG changeset patch
# User pacien <pacien.trangir...@pacien.net>
# Date 1643198916 -3600
# Wed Jan 26 13:08:36 2022 +0100
# Node ID 92eaf2a7d355c27f04ea3bc90019723c0e643475
# Parent 3b6b43a7ace4bf9059c44ef81b630d15986e08ca
# EXP-Topic cl2-cext-prep
revlog: extract entry byte offsets into named constants
Labelling the fields pointed by the given offsets shared by revlog v1 and v2.
diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
--- a/mercurial/cext/revlog.c
+++ b/mercurial/cext/revlog.c
@@ -136,6 +136,20 @@
static const long format_v1 = 1; /* Internal only, could be any number */
static const long format_v2 = 2; /* Internal only, could be any number */
+static const long entry_offset_high = 0;
+static const long entry_offset_offset_flags = 4;
+static const long entry_offset_comp_len = 8;
+static const long entry_offset_uncomp_len = 12;
+static const long entry_offset_base_rev = 16;
+static const long entry_offset_link_rev = 20;
+static const long entry_offset_parent_1 = 24;
+static const long entry_offset_parent_2 = 28;
+static const long entry_offset_node_id = 32;
+static const long entry_offset_sidedata_offset = 64;
+static const long entry_offset_sidedata_comp_len = 72;
+static const long entry_offset_all_comp_mode = 76;
+static const long entry_offset_padding_start = 77;
+
static const char comp_mode_inline = 2;
static const char rank_unknown = -1;
@@ -206,8 +220,8 @@
{
const char *data = index_deref(self, rev);
- ps[0] = getbe32(data + 24);
- ps[1] = getbe32(data + 28);
+ ps[0] = getbe32(data + entry_offset_parent_1);
+ ps[1] = getbe32(data + entry_offset_parent_2);
/* If index file is corrupted, ps[] may point to invalid revisions. So
* there is a risk of buffer overflow to trust them unconditionally. */
@@ -254,12 +268,12 @@
return 0;
data = index_deref(self, rev);
- offset = getbe32(data + 4);
+ offset = getbe32(data + entry_offset_offset_flags);
if (rev == 0) {
/* mask out version number for the first entry */
offset &= 0xFFFF;
} else {
- uint32_t offset_high = getbe32(data);
+ uint32_t offset_high = getbe32(data + entry_offset_high);
offset |= ((uint64_t)offset_high) << 32;
}
return (int64_t)(offset >> 16);
@@ -275,7 +289,7 @@
data = index_deref(self, rev);
- tmp = (int)getbe32(data + 8);
+ tmp = (int)getbe32(data + entry_offset_comp_len);
if (tmp < 0) {
PyErr_Format(PyExc_OverflowError,
"revlog entry size out of bound (%d)", tmp);
@@ -320,7 +334,7 @@
if (data == NULL)
return NULL;
- offset_flags = getbe32(data + 4);
+ offset_flags = getbe32(data + entry_offset_offset_flags);
/*
* The first entry on-disk needs the version number masked out,
* but this doesn't apply if entries are added to an empty index.
@@ -328,17 +342,17 @@
if (self->length && pos == 0)
offset_flags &= 0xFFFF;
else {
- uint32_t offset_high = getbe32(data);
+ uint32_t offset_high = getbe32(data + entry_offset_high);
offset_flags |= ((uint64_t)offset_high) << 32;
}
- comp_len = getbe32(data + 8);
- uncomp_len = getbe32(data + 12);
- base_rev = getbe32(data + 16);
- link_rev = getbe32(data + 20);
- parent_1 = getbe32(data + 24);
- parent_2 = getbe32(data + 28);
- c_node_id = data + 32;
+ comp_len = getbe32(data + entry_offset_comp_len);
+ uncomp_len = getbe32(data + entry_offset_uncomp_len);
+ base_rev = getbe32(data + entry_offset_base_rev);
+ link_rev = getbe32(data + entry_offset_link_rev);
+ parent_1 = getbe32(data + entry_offset_parent_1);
+ parent_2 = getbe32(data + entry_offset_parent_2);
+ c_node_id = data + entry_offset_node_id;
if (self->format_version == format_v1) {
sidedata_offset = 0;
@@ -346,10 +360,12 @@
data_comp_mode = comp_mode_inline;
sidedata_comp_mode = comp_mode_inline;
} else {
- sidedata_offset = getbe64(data + 64);
- sidedata_comp_len = getbe32(data + 72);
- data_comp_mode = data[76] & 3;
- sidedata_comp_mode = ((data[76] >> 2) & 3);
+ sidedata_offset = getbe64(data + entry_offset_sidedata_offset);
+ sidedata_comp_len =
+ getbe32(data + entry_offset_sidedata_comp_len);
+ data_comp_mode = data[entry_offset_all_comp_mode] & 3;
+ sidedata_comp_mode =
+ ((data[entry_offset_all_comp_mode] >> 2) & 3);
}
return Py_BuildValue(tuple_format, offset_flags, comp_len, uncomp_len,
@@ -421,7 +437,7 @@
return NULL;
data = index_deref(self, pos);
- return data ? data + 32 : NULL;
+ return data ? data + entry_offset_node_id : NULL;
}
/*
@@ -504,25 +520,28 @@
}
rev = self->length + self->new_length;
data = self->added + self->entry_size * self->new_length++;
- putbe32(offset_flags >> 32, data);
- putbe32(offset_flags & 0xffffffffU, data + 4);
- putbe32(comp_len, data + 8);
- putbe32(uncomp_len, data + 12);
- putbe32(base_rev, data + 16);
- putbe32(link_rev, data + 20);
- putbe32(parent_1, data + 24);
- putbe32(parent_2, data + 28);
- memcpy(data + 32, c_node_id, c_node_id_len);
+ putbe32(offset_flags >> 32, data + entry_offset_high);
+ putbe32(offset_flags & 0xffffffffU, data + entry_offset_offset_flags);
+ putbe32(comp_len, data + entry_offset_comp_len);
+ putbe32(uncomp_len, data + entry_offset_uncomp_len);
+ putbe32(base_rev, data + entry_offset_base_rev);
+ putbe32(link_rev, data + entry_offset_link_rev);
+ putbe32(parent_1, data + entry_offset_parent_1);
+ putbe32(parent_2, data + entry_offset_parent_2);
+ memcpy(data + entry_offset_node_id, c_node_id, c_node_id_len);
/* Padding since SHA-1 is only 20 bytes for now */
- memset(data + 32 + c_node_id_len, 0, 32 - c_node_id_len);
+ memset(data + entry_offset_node_id + c_node_id_len, 0,
+ entry_offset_node_id - c_node_id_len);
if (self->format_version == format_v2) {
- putbe64(sidedata_offset, data + 64);
- putbe32(sidedata_comp_len, data + 72);
+ putbe64(sidedata_offset, data + entry_offset_sidedata_offset);
+ putbe32(sidedata_comp_len,
+ data + entry_offset_sidedata_comp_len);
comp_field = data_comp_mode & 3;
comp_field = comp_field | (sidedata_comp_mode & 3) << 2;
- data[76] = comp_field;
+ data[entry_offset_all_comp_mode] = comp_field;
/* Padding for 96 bytes alignment */
- memset(data + 77, 0, self->entry_size - 77);
+ memset(data + entry_offset_padding_start, 0,
+ self->entry_size - entry_offset_padding_start);
}
if (self->ntinitialized)
@@ -577,10 +596,12 @@
/* Find the newly added node, offset from the "already on-disk" length
*/
data = self->added + self->entry_size * (rev - self->length);
- putbe64(offset_flags, data);
- putbe64(sidedata_offset, data + 64);
- putbe32(sidedata_comp_len, data + 72);
- data[76] = (data[76] & ~(3 << 2)) | ((comp_mode & 3) << 2);
+ putbe64(offset_flags, data + entry_offset_high);
+ putbe64(sidedata_offset, data + entry_offset_sidedata_offset);
+ putbe32(sidedata_comp_len, data + entry_offset_sidedata_comp_len);
+ data[entry_offset_all_comp_mode] =
+ (data[entry_offset_all_comp_mode] & ~(3 << 2)) |
+ ((comp_mode & 3) << 2);
Py_RETURN_NONE;
}
@@ -1123,7 +1144,7 @@
data = index_deref(self, rev);
if (data == NULL)
return -2;
- result = getbe32(data + 16);
+ result = getbe32(data + entry_offset_base_rev);
if (result > rev) {
PyErr_Format(
@@ -2735,9 +2756,10 @@
while (pos + self->entry_size <= end && pos >= 0) {
uint32_t comp_len, sidedata_comp_len = 0;
/* 3rd element of header is length of compressed inline data */
- comp_len = getbe32(data + pos + 8);
+ comp_len = getbe32(data + pos + entry_offset_comp_len);
if (self->entry_size == v2_entry_size) {
- sidedata_comp_len = getbe32(data + pos + 72);
+ sidedata_comp_len = getbe32(
+ data + pos + entry_offset_sidedata_comp_len);
}
incr = self->entry_size + comp_len + sidedata_comp_len;
if (offsets)
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