89 lines
3.2 KiB
Plaintext
89 lines
3.2 KiB
Plaintext
Minutes of the WINPROF code review
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1/17/91 9-11a
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attending: ANNMC CHUCKC JIMH JONN
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Minutes by JONN
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-- THE FOLLOWING OBSERVATION IS IMPORTANT TO ALL WINDOWS PROGRAMMERS:
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WinProf and the other modules reviewed frequently allocate objects on the
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stack, then pass these objects by far reference to other procedures. This
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is dangerous where the called procedure could use Windows APIs or
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lose control to Windows.
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WINDOWS AND THE WINDOWS APIS CAN RELOCATE THE STACK SEGMENT!
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This means that the far pointer passed to the called procedure may be
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invalidated by a Windows call. Remember that constructors and
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destructors are also called procedures, and that the implicit
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parameter "this" is passed by far reference.
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This occurs in this scenario:
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- Large Model (or where far pointers are used),
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- when objects are allocated on the stack,
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- when pointers to those objects are passed to procedures,
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- when those procedures call Windows APIs or lose control to Windows,
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- and the stack segment is not locked,
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- under Real Mode.
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In particular, BLT dialog objects are often allocated this way.
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Rustan says that he will fix DIALOG_WINDOW::Process() to
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automatically lock the stack segment for the duration of the
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Process() call. A different approach to fixing the problem could be
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to allocate just a pointer on the stack, then allocate the object
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with New; heap objects are always locked.
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-- These modules, and all Windows modules which must run under Real Mode,
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should be unit-tested under real mode. If it survives, try again
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while running Shaker.
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-- General Windows coding practice: For every routine, specify whether it
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calls Windows APIs which could potentially move memory. In
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particular, routines which do not take hParent arguments but which
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can move memory should be clearly marked. Routines which do not and
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will never call Windows APIs should not take an hParent argument.
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-- We should resolve the problem with the two versions of CFGFILE,
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either by upgrading UserProfile to use the new versions, or by
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supporting the old version. CHUCKC will look into this.
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-- CHRISG has observed a speed problem where NetGetDCName is repeated
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when PROFILE::Read fails. This should be fixed so that PROFILE::Read
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caches an empty profile even when it fails. Thus, the first
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PROFILE::* call will fail if the profile is inaccessible, but subsequent
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calls will use the (empty) cached profile.
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-- Callers of WinNet's MapError should not assume that
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(usNetErr != 0) => (wWnErr != 0).
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-- Enable the WNetRestoreConnections bit in WNetGetCaps. WNRC(0) should
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fail, only WNRC(1) is supported.
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-- We should disable WNetAddConnection, ifdef out its code (return
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WN_NOT_SUPPORTED), disable its WNetGetCaps bit.
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-- JONN should upgrade to Win31 beta as soon as a semi-stable version is
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available which runs Net APIs.
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-- JONN should check: Does SetNetError also prepare the error text?
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-- JONN should file a Sev 4 bug against the use of locked memory for
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the user profile cache in UserProfile under Windows.
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-- CHUCKC will look into the possibility of caching the DC name.
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-- The pnlsUNCResourceName parameter to PROFILE::Load should be removed
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as it is never used.
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