[PATCH 07 of 10 lazy-changelog-parse] changelog: lazily parse files

[Martin von Zweigbergk]

What do you think about folding in the following? Seems correct? Would
it be noticeably slower with the extra array slicing?

diff -r 18f6505b3b79 mercurial/changelog.py
--- a/mercurial/changelog.py    Sun Mar 06 14:31:06 2016 -0800
+++ b/mercurial/changelog.py    Mon Mar 07 21:37:24 2016 -0800
@@ -196,12 +196,7 @@ class changelogrevision(object):
         nl3 = text.index('\n', nl2 + 1)
         self._rawdateextra = text[nl2 + 1:nl3]

-        # The list of files may be empty. Which means nl3 is the first of the
-        # double newline that precedes the description.
-        if nl3 == doublenl:
-            self._rawfiles = None
-        else:
-            self._rawfiles = text[nl3 + 1:doublenl]
+        self._rawfiles = text[nl3:doublenl]

         return self

@@ -247,10 +242,7 @@ class changelogrevision(object):

     @property
     def files(self):
-        if self._rawfiles is None:
-            return []
-
-        return self._rawfiles.split('\n')
+        return self._rawfiles.split('\n')[1:]

     @property
     def description(self):



On Sun, Mar 6, 2016 at 3:58 PM, Gregory Szorc <gregory.szorc at gmail.com> wrote:
> # HG changeset patch
> # User Gregory Szorc <gregory.szorc at gmail.com>
> # Date 1457303466 28800
> #      Sun Mar 06 14:31:06 2016 -0800
> # Node ID e37bac9adf9215f82850e7b105e3e47e1bee3d7a
> # Parent  7559d2bcdaeb320212bf8d37e0e5e2075dec6d18
> changelog: lazily parse files
>
> More of the same.
>
> Again, modest revset performance wins:
>
> author(mpm)
> 0.896565
> 0.822961
> 0.805156
>
> desc(bug)
> 0.887169
> 0.847054
> 0.798101
>
> date(2015)
> 0.878797
> 0.811613
> 0.786689
>
> extra(rebase_source)
> 0.865446
> 0.797756
> 0.777408
>
>  author(mpm) or author(greg)
> 1.801832
> 1.668172
> 1.626547
>
> author(mpm) or desc(bug)
> 1.812438
> 1.677608
> 1.613941
>
> date(2015) or branch(default)
> 0.968276
> 0.896032
> 0.869017
>
> diff --git a/mercurial/changelog.py b/mercurial/changelog.py
> --- a/mercurial/changelog.py
> +++ b/mercurial/changelog.py
> @@ -148,17 +148,17 @@ class changelogrevision(object):
>      Changelog revisions consist of multiple pieces of data, including
>      the manifest node, user, and date. This object exposes a view into
>      the parsed object.
>      """
>
>      __slots__ = (
>          '_rawdateextra',
>          '_rawdesc',
> -        'files',
> +        '_rawfiles',
>          '_rawmanifest',
>          '_rawuser',
>      )
>
>      def __new__(cls, text):
>          if not text:
>              return _changelogrevision(
>                  manifest=nullid,
> @@ -191,18 +191,22 @@ class changelogrevision(object):
>          self._rawmanifest = text[0:nl1]
>
>          nl2 = text.index('\n', nl1 + 1)
>          self._rawuser = text[nl1 + 1:nl2]
>
>          nl3 = text.index('\n', nl2 + 1)
>          self._rawdateextra = text[nl2 + 1:nl3]
>
> -        l = text[:doublenl].split('\n')
> -        self.files = l[3:]
> +        # The list of files may be empty. Which means nl3 is the first of the
> +        # double newline that precedes the description.
> +        if nl3 == doublenl:
> +            self._rawfiles = None
> +        else:
> +            self._rawfiles = text[nl3 + 1:doublenl]
>
>          return self
>
>      @property
>      def manifest(self):
>          return bin(self._rawmanifest)
>
>      @property
> @@ -237,16 +241,23 @@ class changelogrevision(object):
>      def extra(self):
>          raw = self._rawextra
>          if raw is None:
>              return _defaultextra
>
>          return decodeextra(raw)
>
>      @property
> +    def files(self):
> +        if self._rawfiles is None:
> +            return []
> +
> +        return self._rawfiles.split('\n')
> +
> +    @property
>      def description(self):
>          return encoding.tolocal(self._rawdesc)
>
>  class changelog(revlog.revlog):
>      def __init__(self, opener):
>          revlog.revlog.__init__(self, opener, "00changelog.i")
>          if self._initempty:
>              # changelogs don't benefit from generaldelta
> _______________________________________________
> Mercurial-devel mailing list
> Mercurial-devel at mercurial-scm.org
> https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel