[PATCH 3 of 7 V5] sparse-revlog: add a `index_segment_span` function in C

Boris Feld boris.feld at octobus.net
Thu Nov 22 13:08:05 EST 2018


# HG changeset patch
# User Boris Feld <boris.feld at octobus.net>
# Date 1541785396 -3600
#      Fri Nov 09 18:43:16 2018 +0100
# Node ID 4ad3891a07ed83cda837db8d0cbe285ebb377869
# Parent  18864760091a1622d0404e9a87923cf2b1b82082
# EXP-Topic sparse-perf
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 4ad3891a07ed
sparse-revlog: add a `index_segment_span` function in C

We are about to implement a native version of `slicechunktodensity`. For
clarity, we introduce the helper functions first. This new function provides
an efficient way to retrieve some of the information needed by
`slicechunktodensity`.

diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
--- a/mercurial/cext/revlog.c
+++ b/mercurial/cext/revlog.c
@@ -1048,6 +1048,35 @@ bail:
 	return NULL;
 }
 
+static inline int64_t
+index_segment_span(indexObject *self, Py_ssize_t start_rev, Py_ssize_t end_rev)
+{
+	int64_t start_offset;
+	int64_t end_offset;
+	int end_size;
+	start_offset = index_get_start(self, start_rev);
+	if (start_offset < 0) {
+		return -1;
+	}
+	end_offset = index_get_start(self, end_rev);
+	if (end_offset < 0) {
+		return -1;
+	}
+	end_size = index_get_length(self, end_rev);
+	if (end_size < 0) {
+		return -1;
+	}
+	if (end_offset < start_offset) {
+
+		PyErr_Format(PyExc_ValueError,
+		             "corrupted revlog index: inconsistent offset "
+		             "between revisions (%lld) and (%lld)",
+		             (long long)start_rev, (long long)end_offset);
+		return -1;
+	}
+	return (end_offset - start_offset) + (int64_t)end_size;
+}
+
 static inline int nt_level(const char *node, Py_ssize_t level)
 {
 	int v = node[level >> 1];


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