The problem was that, if we killed export when some graphic was
being converted, or some external template was being handled, it
would only cancel that process, and then it would just continue.
To deal with that, we need to do a few things:
1. Modify the return values for some of the Converters routines,
and similarly the routines for external templates, so we can
tell when something has been canceled.
2. Throw an exception from InsetGraphics or InsetExternal when this
has happened during export, but ONLY when the Buffer is a clone.
We shouldn't be able to 'cancel' export when we're, say, generating
code for the preview pane, but this keeps us on the safe side..
The exception then has to be caught, obviously, back in the export
routines in Buffer.
Probably Coverity will be unhappy about something here, but I'll
deal with that problem as it arises.
This is mandatory for some features (such as bookmarks,pdfusetitle)
to work, and only a handful of drivers can be auto-detected by hyperref.
Fixes: #6418
Since CheckTeX itself processes the tex file, a synchronous run with
a TeX process can lead to all sorts of conflicts, including crashes.
Fixes: #7434.
This is needed for cases where the temp file has to be manually removed
at some point (e.g., if temp files are used as conversion target, and
the initial file only serves as a placeholder), since QTemporaryFile
objects cannot be manually removed at least on Windows (they are always
kept open internally even after close()). See
http://lists.qt-project.org/pipermail/interest/2013-August/008352.html
In order to avoid race conditions due to duplicate names (the issue why
the old method was removed), we record all used temp file names.
Fixes: #9139
Now the helper class contains logic that checks whether buffer are
known before closing them. This avoids potential crashes.
Use it in different places to siplify code. It is not clear at this
point whether it should be used everywhere.
Followup to bug #10847.
Along the lines suggested by JMarc, we now collect the list of bibfiles
in use in the updateBuffer routines. This actually does simplify the code
quite a bit. See the discussion there for reasons to go this way.
No intended change of behavior. The ones that use DocIterators and
ParIterators cannot yet be changed, but they could be if we provided
the right sorts of methods, perhaps.
Basically, everything that does not depend on a BufferView should move
there. Some methods that do not seem to need a BufferView, like
selHandle or IdxFirst or push actually depend on it and could not be
moved.
This allows to simplify a few uses of recordUndo helpers.
- Move some methods to DocIterator: nextMath, prevMath, getPossibleLabel,
getEncoding;
- Move some methods to CursorData: setCursor, setCursorSelectionTo,
(setCursorTo|normal|reset)Anchor, (set|clear)Selection,
sel(|ection)(Begin|End), selectionAsString, info, currentState,
(mark|clear|check)NewWordPosition, fixIfBroken, sanitize, all undo
related methods, reset, isInside, leaveInset, current mode;
- kill some unused methods: macromode, replaceWord, setScreenPos, touch,
markInsert, markErase;
- Move code around to group things, and add a few comments (a lot remains to be done).
This changes lead to some related changes in other classes: removal,
change of parameter.
No intended change.
Scanning is rather slow, so this improves performance in specific
situations (multiple inclusion of larger files in master/child or
chapterbib context)
In some cases, it is possible that the BufferPositionMap has
dangling pointers. We thus check whether the Buffer is loaded
before accessing it.
Fixes: #10766
(cherry picked from commit 4f50cbcfe4)
Allow a LaTeX backend to run external commands after user confirmation.
This is a per document and per machine setting. The authorization has
to be given through the document settings pane, but is not recorded in
the document itself. Moving the document to either another computer or
another directory on the same computer revokes the authorization.
This can also be done by right clicking the red icon that appears in
the status bar when a document is marked as one requiring shell escape.
The patch also checks whether the user has added the -shell-escape
option to a LaTeX converter and nags the user to remove the option
(which would be used for all documents) in favor of the (per document)
support offered by LyX.
This commit does a bulk fix of incorrect annotations (comments) at the
end of namespaces.
The commit was generated by initially running clang-format, and then
from the diff of the result extracting the hunks corresponding to
fixes of namespace comments. The changes being applied and all the
results have been manually reviewed. The source code successfully
builds on macOS.
Further details on the steps below, in case they're of interest to
someone else in the future.
1. Checkout a fresh and up to date version of src/
git pull && git checkout -- src && git status src
2. Ensure there's a suitable .clang-format in place, i.e. with options
to fix the comment at the end of namespaces, including:
FixNamespaceComments: true
SpacesBeforeTrailingComments: 1
and that clang-format is >= 5.0.0, by doing e.g.:
clang-format -dump-config | grep Comments:
clang-format --version
3. Apply clang-format to the source:
clang-format -i $(find src -name "*.cpp" -or -name "*.h")
4. Create and filter out hunks related to fixing the namespace
git diff -U0 src > tmp.patch
grepdiff '^} // namespace' --output-matching=hunk tmp.patch > fix_namespace.patch
5. Filter out hunks corresponding to simple fixes into to a separate patch:
pcregrep -M -e '^diff[^\n]+\nindex[^\n]+\n--- [^\n]+\n\+\+\+ [^\n]+\n' \
-e '^@@ -[0-9]+ \+[0-9]+ @@[^\n]*\n-\}[^\n]*\n\+\}[^\n]*\n' \
fix_namespace.patch > fix_namespace_simple.patch
6. Manually review the simple patch and then apply it, after first
restoring the source.
git checkout -- src
patch -p1 < fix_namespace_simple.path
7. Manually review the (simple) changes and then stage the changes
git diff src
git add src
8. Again apply clang-format and filter out hunks related to any
remaining fixes to the namespace, this time filter with more
context. There will be fewer hunks as all the simple cases have
already been handled:
clang-format -i $(find src -name "*.cpp" -or -name "*.h")
git diff src > tmp.patch
grepdiff '^} // namespace' --output-matching=hunk tmp.patch > fix_namespace2.patch
9. Manually review/edit the resulting patch file to remove hunks for files
which need to be dealt with manually, noting the file names and
line numbers. Then restore files to as before applying clang-format
and apply the patch:
git checkout src
patch -p1 < fix_namespace2.patch
10. Manually fix the files noted in the previous step. Stage files,
review changes and commit.
Several comments in the code point to the fact that hidden buffers are assumed
to be clean.
The other solution was to adapt the closing & saving code to take into account
hidden dirty buffers. Experience shows that it is more useful to unhide the
buffers at the moment of the external modification, in the context of a git
workflow where one has to reload the modified children buffers one-by-one.
Fixes crash at #10603
When the Buffer is notified to be externally modified, check that the
file contents have changed using the checksum.
Document the shortcoming of FileMonitorBlocker.
Fixes#10642.
- Adds a currentZoom variable which holds the current zoom level.
- The zoom stored in preferences is used as default zoom level (default binding:
M+0).
- The currentZoom is saved and restored via QSettings.
- Adds LFUN buffer-zoom for (re)setting zoom.
Use Length instead of HSpace for math_indentation and rename it to mathindent.
Get rid of the string version.
Rename (g|s)etMathIndentation() to (g|s)etMathIndent().
Remove the HSpace class altogether.
Some cleanups to parindent support to look like mathindent.
The error is reported in the GUI, but for the terminal we must write
explicitly to STDERR.
For a specific example of this type of exception, see the previous
commit, 72c3dbd.
Introduce a distinction between being read-only and having the read-only flag. A
buffer is read-only if either it has been externally modified or if it has the
read-only flag.
For biblatex, we need the file name as it was entered in the inset
(abs path, rel path, only file name) in order to resolve it properly
for the export (as in the BibTeX inset intself).
Therefore, we now store a pair<docstring, FileName>.
A FileNamePairList has been added to FileNameList for this purpose.
Macro nesting is now recorded into the macro inset itself. This allows
the ArgumentProxy inset to determine whether it is editable or not by
looking at its macro.
Remove code in the metrics and draw methods of ArgumentProxy: this
code is AFAICS not active anymore, since arguments are linearized into
math rows.
Use Changer idiom to change locally the values of MecticsInfo::base.macro_nesting.
Addressing #10481.
This patch adds the new 'needauth' option for converters launching
external programs that are capable of running arbitrary code on behalf
of the user. These converters won't be run unless the user gives explicit
authorization, which is asked on-demand when the converter is about to
be run (question is not asked if the file is cached and calling the
converter is not needed).
The user prompt has a 3rd button so that he/she's not prompted again
for (any converter over) the same document (identified through
buffer->absFileName()).
Two preference options are added:
lyxrc.use_converter_needauth_forbidden disables any converter with
the 'needauth' option, which is meant to force user to an explicit
action via the preferences pane, before being able to use advanced
converters that can potentially bring security threats;
lyxrc.use_converter_needauth enables prompting the user for 'needauth'
converters, or bypasses the check if not enabled, falling back to the
previous behavior.
So, the first option is for maximum security, the second is for
maximum usability.
No newline is written after \begin{document}, such that
the afterParbreak method would return false. This misleads
the code that outputs a display math in an ulem command
to emit a newline command instead of \noindent, causing
latex errors. This occurs only if the math is at the very
start of a document, without anything before it.
This enables error reporting for the preamble, provided the preamble is written
using the new InPreamble layouts.
In the future, I find it preferable to deprecate the usual preamble in favour of
InPreamble layouts rather than implementing error reporting for the usual
preamble. This requires some improvements to code editing in the buffer view
first (line breaking behaviour, syntax highlighting).
TexRow now returns a range {start, end} when looking up a particular row.
Reverse-search now selects the whole range instead of simply moving the cursor.
XeTeX with TeX fonts is only safe with ASCII input encoding (see #9740)
and we therefore force "ascii" when exporting with XeTeX and 8-bit TeX-fonts.
However, "utf8-plain" is a "power-user" option, which allows to switch off LyX's
encoding of the LaTeX file:
keep this also for "XeTeX with TeX fonts".
The user is responsible to ensure all characters can be processed and are
correctly shown in the output. The provided test sample shows the problems
with this encoding without special measures (like loading fontspec in the
user-preamble or a document class).
This is a mechanical replacement. For now it seems that unique_ptrs are
essentially used for exception-safety. More could certainly be done to clarify
pointer ownership in general.
(#8738)
For efficiency, we add a new flag to the buffer indicating when changes are
present. This flag is updated at each buffer update, and also when explicitly
requested via a dispatch result flag.
Deriving from std::vector to provide helper functions appears a touch
excessive. Use typedef instead and move helper functions to the base class. New
header Toc.h provided to replace forward-declarations.
Remove TocIterator which is useless.
Increment LyX format to 504.
With this new parameter, the user can indicate that some other parameters that
are frequently switched must not be recorded in the file (as if they were a
setting specific to the user or transient, rather than a document setting). This
will play nicer with version control systems.
See the discussion, e.g.:
http://thread.gmane.org/gmane.editors.lyx.devel/157824/focus=157993 (third
solution mentioned)
TODO:
* The interface remains to be set up. We cannot change this setting from LyX
for now.
* If save_transient_properties is false, we should read the user setting as a
per-user-per-document (session) setting (e.g. like the cursor position).
* Once the above is done, we can treat \justification the same way (but it would
be even better if \justification was moved to lyxrc).
The current behaviour of the \origin parameter replaces relative file names
with the absolute original names if a document has been moved even if the
files have been moved as well. This behaviour is annoying e.g. for editing the
LyX docs in a git checkout.
Now file names are only replaced if the referenced file sdo not exist.
whether a given child Buffer is also a child of some other parent.
Then do the releasing or resetting where this method is called.
There should be no change of behavior with this patch.
LyX format, create a backup of the original file. We put it in the backup
directory, if one exists, otherwise in the directory the original file is
in. This is the same strategy as for normal backups. Basically, the only
diferences are: (i) what name we use and (ii) we do not over-write any
backups that may already exist.
Actually, the changed tests were used to prevent overwriting the encoding
changed in Buffer::writeLaTeX with a language-default encoding.
This is still required for XeTeX with TeX-fonts unless a proper solution is found.
Documents with more than one encoding and TeX-fonts fail with LuaTeX,
as "luainputenc" can only handle one encoding.
and record an undo call. This deals with the problem of marking
the Buffer dirty, as well.
Move LFUN_BUFFER_TOGGLE_COMPRESSION and LFUN_BUFFER_TOGGLE_OUTPUT_SYNC
to Buffer.cpp, and add an undo call.
Sometimes when compilation fails a PDF file is created but is empty
and the viewer gives an error when trying to view it. One such
example is compiling the current lib/examples/PDF-comment.lyx file
with TeX fonts and the following version of LuaTeX:
beta-0.80.0 (TeX Live 2015) (rev 5238)
Fixes output for 3 of the 4 test lyx-files.
Includes "FIXME"s at places where further action is required to get the XeTeX
export right but I don't know how.
* TexRow now computes rows from a DocIterator. In practice, the cursor
highlighting is now correct inside insets, it is no longer restricted to the
topmost level. It certainly also makes forward-search more precise.
* Added the option to disable a texrow when not needed, for perf.
* Fixed a bug where the last paragraph was not properly highlighted.
Limitations:
* TexRow still does not handle: math (e.g. multi-cell), sub-captions, inset
arguments.
* New TOC "math-macro". This means that math macros can now be accessed in the
outline pane in their order of appearance or in alphabetical order, and can be
searched using the filter.
* Lists of floats now show subfloats deeper in the navigation menu
* The arbitrary 30 element cut-off after which nothing is shown except "Open
Navigator..." is removed. Menus now have no limit in size, so Qt may display
them scrollable. In exchange, we always show "Open outliner..." at the
beginning. I tested for performance issues with a rather complex document and
it is fine; but this does not exclude corner cases with lots of TOC entries of
a certain kind. If necessary, populating the navigation sub-menu should be
delayed like the main menu.
* Elements that do not contribute to the output (e.g. in a note, a disabled
branch) are now preceded with a symbol indicating this status. (The machinery
was already there; I wonder why it was not implemented already.) I have chosen
U+274E NEGATIVE SQUARED CROSS MARK.
* Fix the contextual menus in the outliner (bug introduced at 94e992c5).
* Toc item now move to the caption when present, but first center on the float,
to prevent the situation where the caption is at the top of the screen and the
contents of the float is off-screen above the caption.
(Internally, the action of the toc items can now be customised)
* Fix the LyXHTML output. Disabled captions no longer appear in the list of
figures.
We introduce TocBuilder for building TOCs that take into account both float
insets and their captions.
* Floats without caption are shown with their content.
* Floats with a caption are shown with their caption, but clicking the entry now
correctly moves to the float and not to the caption.
* Subsequent captions produce additional entries in the TOC.
* Figures and subfigures are correctly ordered in the outliner.
* New TOC "senseless" for captions appearing alone (a bit like broken references
are still displayed in the menu and outliner).
* Disable LFUN_CAPTION_INSERT if there is already a caption in a listing
Known issues:
* Inconsistent output for includes located inside floats
* We should record the end of the float in addition of the beginning for a more
accurate cursor -> outliner entry conversion
Fix bugs #6501 and #7359.
* Selection highlighting has been broken since a conflict with
reverse-search was repaired (at 00a62b7c), is now fixed.
* The selection highlighting was not accurate, for LaTeX formats (in
full source view), and meaningless, for non LaTeX formats.
* fix regression at cc00b9aa: force_getcontent_ was always true
therefore the code to detect changes in the generated source was
dead. The consequence is that the source view would jump to the
beginning at each updateView() even if no change occurred. Cc00b9aa
was meant to fix#5600, which I cannot reproduce with the new
implementation.
* Various improvements:
* When the position-to-line conversion is unavailable (LyXHTML, LyX
source, etc.) we focus on the first difference instead.
* Get some space around the cursor
* Respect the scrollbars
* Highlight with QTextEdit::ExtraSelections instead of cursor
selection (the latter used to break syntax highlighting of the
TeX code... which was not so much of an issue before because the
wrong part was selected)
Known issues:
* The highlighting is off by one line in very last paragraph of a
document. This appears to be a bug in TexRow.cpp.
* The highlighting is off for any kind of inset. This could be
solved by adapting TexRow so that it accepts CursorSlices as
and argument for the conversion to line number. (this is bug
#4725)
In order to adjust the path of an included file, when deciding
whether the document was moved or not, it is not sufficient
comparing the paths because the document could have been accessed
through a symbolic link.
This is done only inside LFUN_BUFFER_VIEW_CACHE so as to preserve
the benefits of caching in other places.
Without this commit, if a converter or a user (re)moves the preview
file and then calls buffer-view-cache LyX will launch the viewer for
a file that does not exist.
For a discussion and use case, see:
https://www.mail-archive.com/search?l=mid&q=55D393D7.6050403@lyx.org
It is now possible opening documents that where manually moved to a
different location after they were saved and still produce an output.
Indeed, (hopefully) all needed included files are now still found.
When the moved document is saved again, all paths are accordingly updated.
Of course, for this to work, a document has to be saved in Format 490,
at least.
As an example, after converting the user guide to the last format, it can
be copied anywhere and opened without the need of adapting the paths of
included files or moving them to a proper place.
There is one glitch I am aware of. When moving a child document (but not
the master) the path to the master is correctly updated but it won't be
recognized as such. This is because LyX checks that the parent actually
includes this document but, of course, being the parent document not
touched, it appears not including this child. Anyway, it will also occur
when saving the child to a different location and the user is warned
on the terminal about this fact when the moved child is loaded.
However, there is no problem when it is the master that has been moved.
The "save-as" part of the bug is fixed by extending the \textclass tag
such that, if a local layout file is used, its path relative to the
document directory is now stored together with the name. If a relative
path cannot be used, an absolute one is used but, in this case, the
document is not usable on a different platform.
The "copy" part is fixed by introducing a new \origin tag, which is
written when the file is saved. This tag stores the absolute path of
the document directory. If the document is manually copied to a
different location, the local layout file is retrivied by using
\origin (which is only updated on save).
This new tag may prove useful also for locating other files when the
document is manually moved to a different directory.
As in the original implementation the files needed for the layout
(for example, a latex class) had to be in the same directory as the
layout file, this directory has also to be added to TEXINPUTS.
The document iterator now skips math insets and insets like notes where spell check is disabled.
The continuous spell checking is part of the row painter drawing and the spell check disabled state
has to be passed down recursively while doing the inset painting.
As Enrico said, the user might have installed a package that was
missing (in which case the .tex file would not have changed).
Another reason is that changing some document settings did not
automatically lead to a fresh compile after an error (#9061).
Our old mechanism for detemining whether there was an error was to
check if the dependent file existed in the temporary directory. If
it did not exist, that meant it was removed, presumably because
there was an error during compilation. That mechanism cannot be used
anymore because we keep the files around even after error because of
the "Show Output Anyway" button (09700d5b). This commit implements a
more straightforward way of checking whether there was an error in
the previous preview by simply storing the success of last compile
in a buffer variable.
Building on cd8be655, we still allow viewing a produced PDF even if
there were compilation errors. However, now the user must click the
"Show Output Anyway" button in the LaTeX Errors dialog. The reason
is that before, there was a chance that the user would not realize
there was an error (because the PDF would be shown over the error
dialog). The approach in this commit makes it more clear that there
is an error.
A new LFUN is introduced, LFUN_BUFFER_VIEW_CACHE. It is useful not
just for the implementation of the "Show Output Anyway" button, but
also to show the last compiled version of a document, which can save
time if a document takes a long time to compile (e.g. heavy use of
knitr).
The only real user was Text::insertStringAsLine, but this got changed
in commit 2c7152ab.
While not other place did read the value, there is a side effect of
setAutobreakRow that merges exiting paragraphs. However, this is used
in two situations
* some constructors, where the inset is empty;
* InsetTabular::toggleFixedWidth, which actually contains itself some
code to merge paragraphs.
Therefore the member and all associated code can be removed safely.
If LyX thinks the export was successful but no output file was
produced for preview, then something is wrong (most likely LyX
did not detect an error that occurred during export).
Also clean up some logic.
A PDF is often still produced after a LaTeX error.
If there was an error when exporting a PDF, we now give an error
and the PDF (if it exists), where before we gave the error and
not the PDF. The GUI and command line behaviors are consistent:
in the GUI an error is given and the PDF is viewed; on the
command line, a non-zero exit code is given and a PDF is created.
This also solves what was in my mind an inconsistency: if the user
"updated" a document and there was an error, the resulting
PDF would be shown; but if the user viewed a document and there
was an error, the document would not be shown.
Note that this applies to all output formats, not just PDF.
For discussion, see:
https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg186454.html
Rename recordUndoFullDocument to recordUndoFullBuffer.
Separate the notion of recording changes to paragraphs and recording changes in buffer parameters.
Audit every user of recordUndoFullDocument and replace it with either recordUndoBufferParams or recordUndoFullBuffer. Add comments to identify remaining work.
Our TempFile class uses QTemporaryFile internally, and, on Windows,
this keeps the file locked so that we cannot rename it. So we have
to release the lock.
Add display_pixel_ratio to buffer params to use it for displays with high resolution.
It holds the highest ratio between physical pixels and device-independent pixels of the LyX application.
Preview snippets will be generated using this value to get high resolution preview.
FileName::tempName() created a new temp file name by using qt to create a
temporary file with a unique name, and then deleting that file and returning
the name. This was unsafe, since other processes or even other threads of the
running LyX could create files with the same name between deletion and then
using the temp name.
This is fixed by using the TempFile class instead. As a side effect, a few
cases where the temp files were not deleted after usage were fixed as well.
The only place that is still unsafe is createTmpDir().
- The TempFile class guarantees to generate a file name, we are not limited to
100 tries of a predictable scheme anymore, which could break if LyX
frequently crashes.
- The temp file name generation has no race condition against another LyX
instance in the same directory anymore.
- Symlinks survive saving again (regression of 10364082c8).
* remove unused class TexStream.
* remove unused virtual method Inset::cellXOffset
* remove second argument of FileDialog constructor, which was actually
not used
* remove some dead local code
* remove some unused private members of classes
* in InsetMathNest::updateBuffer, fix the logic of a test
for possible thread conflicts, of the sort Georg resolved at
6a30211f. I have made static variables const where possible,
and marked cases that looked potentially problematic with the
comment:
// FIXME THREAD
Many of these definitely are vulnerable to concurrent access, such
as the static variables declared at the start of output_latex.cpp.
Suppose, e.g., we were outputting latex and also displaying the
source of a different document.
I'd appreciate it if others could grep for "FIXME THREAD" and see
if some of these are harmless, or what.
http://marc.info/?l=lyx-devel&m=138590578911716&w=2
If you look at Buffer.cpp, around line 4351, there was a comment about bug 5699. We are seeing the
same crash. The problem is that, although the master does have a GUI, that GUI is in a different window. So the structureChanged() call we do during updateBuffer() is for the TOC in that window, not the TOC in the window we are actually in. So our TocModel::toc_ has been reset and is invalid, though the widget itself has not been updated and looks fine.
This patch tests whether the master is in the same window as the buffer we are updating.
A problem remains, which is noted in a comment.
In e02df14 the return type of doExport was changed from bool to ExportStatus.
All calls except this one were adjusted. This one did now fail because the
numercial value of ExportSuccess is 0.
The new HTML clipboard export could cause error message boxes on copying
data to the clipboard (bug #8866). These are now suppressed, like all other
errors which might occur for preparing the clipboard data.
LyX, lyx2lyx and tex2lyx produce now all the same version indicator consisting
only of the major and minor version. It is not decided yet whether future
development versions will add a -dev suffix, but for 2.1.0 this change fixes
the inconsistencies.
These should be used if any new style needs to be introduced in the stable
2.1 series: If the ForceLocal flag of the style is set, it will always be
written to the document header, so that even older 2.1 versions can read
and correctly output the document.
Move the handling of branch-(de)activate(master) to Buffer. This code was moved to Bufferview in [3a03e71c/lyxgit] because a cursor was necessary to call Undo::recordUndoFullDocument(). However, it turns out that the undo code is already prepared to handle an empty cursor (and do nothing in this case).
Therefore we do that and move the branch code to Buffer where it belongs.
Note that there was a bug in the previous code that broke undo support: recordUndo should always be called _before_ doing any change.
each failure.
There are several places I was not sure what to do. These are marked
by comments beginning "LASSERT:" so they can be found easily. At the
moment, they are at:
Author.cpp:105: // LASSERT: What should we do here?
Author.cpp:121: // LASSERT: What should we do here?
Buffer.cpp:4525: // LASSERT: Is it safe to continue here, or should we just return?
Cursor.cpp:345: // LASSERT: Is it safe to continue here, or should we return?
Cursor.cpp:403: // LASSERT: Is it safe to continue here, or should we return?
Cursor.cpp:1143: // LASSERT: There have been several bugs around this code, that seem
CursorSlice.cpp:83: // LASSERT: This should only ever be called from an InsetMath.
CursorSlice.cpp:92: // LASSERT: This should only ever be called from an InsetMath.
LayoutFile.cpp:303: // LASSERT: Why would this fail?
Text.cpp:995: // LASSERT: Is it safe to continue here?
This was a simple logic error that crept in during refactoring:
If the format does not match, and the converted file has been read,
the string must not be read.
As discussed on the list. No automatic contents detection is done, the user
needs to use the special paste menu instead. I used the new TempFile class
for safe temporary file handling.
The documentation would go into section 2.2 of UserGuide.lyx, but I am not
allowed to edit that document.
