util: provide a helper function to estimate RAM size
For POSIX systems, it uses sysconf. For Windows, it uses the win32 API
directly.
Differential Revision: https://phab.mercurial-scm.org/D8644
--- a/mercurial/configitems.py Thu Jul 02 19:59:59 2020 +0200
+++ b/mercurial/configitems.py Tue Jun 09 11:22:31 2020 +0200
@@ -1231,6 +1231,10 @@
b'ui', b'askusername', default=False,
)
coreconfigitem(
+ b'ui', b'available-memory', default=None,
+)
+
+coreconfigitem(
b'ui', b'clonebundlefallback', default=False,
)
coreconfigitem(
--- a/mercurial/ui.py Thu Jul 02 19:59:59 2020 +0200
+++ b/mercurial/ui.py Tue Jun 09 11:22:31 2020 +0200
@@ -2119,6 +2119,22 @@
if (b'ui', b'quiet') in overrides:
self.fixconfig(section=b'ui')
+ def estimatememory(self):
+ """Provide an estimate for the available system memory in Bytes.
+
+ This can be overriden via ui.available-memory. It returns None, if
+ no estimate can be computed.
+ """
+ value = self.config(b'ui', b'available-memory')
+ if value is not None:
+ try:
+ return util.sizetoint(value)
+ except error.ParseError:
+ raise error.ConfigError(
+ _(b"ui.available-memory value is invalid ('%s')") % value
+ )
+ return util._estimatememory()
+
class paths(dict):
"""Represents a collection of paths and their configs.
--- a/mercurial/util.py Thu Jul 02 19:59:59 2020 +0200
+++ b/mercurial/util.py Tue Jun 09 11:22:31 2020 +0200
@@ -3626,3 +3626,44 @@
locale.setlocale(locale.LC_CTYPE, oldloc)
else:
yield
+
+
+def _estimatememory():
+ """Provide an estimate for the available system memory in Bytes.
+
+ If no estimate can be provided on the platform, returns None.
+ """
+ if pycompat.sysplatform.startswith(b'win'):
+ # On Windows, use the GlobalMemoryStatusEx kernel function directly.
+ from ctypes import c_long as DWORD, c_ulonglong as DWORDLONG
+ from ctypes.wintypes import Structure, byref, sizeof, windll
+
+ class MEMORYSTATUSEX(Structure):
+ _fields_ = [
+ ('dwLength', DWORD),
+ ('dwMemoryLoad', DWORD),
+ ('ullTotalPhys', DWORDLONG),
+ ('ullAvailPhys', DWORDLONG),
+ ('ullTotalPageFile', DWORDLONG),
+ ('ullAvailPageFile', DWORDLONG),
+ ('ullTotalVirtual', DWORDLONG),
+ ('ullAvailVirtual', DWORDLONG),
+ ('ullExtendedVirtual', DWORDLONG),
+ ]
+
+ x = MEMORYSTATUSEX()
+ x.dwLength = sizeof(x)
+ windll.kernel32.GlobalMemoryStatusEx(byref(x))
+ return x.ullAvailPhys
+
+ # On newer Unix-like systems and Mac OSX, the sysconf interface
+ # can be used. _SC_PAGE_SIZE is part of POSIX; _SC_PHYS_PAGES
+ # seems to be implemented on most systems.
+ try:
+ pagesize = os.sysconf(os.sysconf_names['SC_PAGE_SIZE'])
+ pages = os.sysconf(os.sysconf_names['SC_PHYS_PAGES'])
+ return pagesize * pages
+ except OSError: # sysconf can fail
+ pass
+ except KeyError: # unknown parameter
+ pass