442a87cc0a Add a test wallet_reorgsrestore (Antoine Riard)
40ede992d9 Modify wallet tx status if has been reorged out (Antoine Riard)
7e89994133 Remove SyncTransaction for conflicted txn in CWallet::BlockConnected (Antoine Riard)
a31be09bfd Encapsulate tx status in a Confirmation struct (Antoine Riard)
Pull request description:
While working on #15931, I've tried to rationalize tx state management to ease integration of block height tracking per-wallet tx. We currently rely on a combination of `hashBlock` and `nIndex` with magic value to determine tx confirmation, conflicted or abandoned state. It's hard to reason and error-prone. To solve that, we encapsulate these fields in a `TxConfirmation` struct and introduce a `TxState` member that we update accordingly at block connection/disconnection.
Following jnewbery [recommendation](https://github.com/bitcoin/bitcoin/pull/15931#discussion_r312576506), I've taken these changes in its own commit, and open a PR to get them first. It would ease review of aforementioned PR, but above all should ease fixing of long-term issues like :
* https://github.com/bitcoin/bitcoin/issues/7315 (but maybe we should abandon abandontransaction or relieve it to only free outpoints not track the transaction as abandoned in itself, need its own discussion)
* https://github.com/bitcoin/bitcoin/issues/8692 where we should cancel conflicted state of transactions chain smoothly
* `MarkConflicted` in `LoadToWallet` is likely useless if we track conflicts rights at block connection
Main changes of this PR to get right are tx update in `AddToWallet` and serialization/deserialization logic.
ACKs for top commit:
meshcollider:
Light re-Code Review ACK 442a87cc0a
ryanofsky:
utACK 442a87cc0a. Changes since last review are switching from `hasChain` to `LockChain` and removing chain lock in `WalletBatch::LoadWallet` that's redundant with the new lock still added in `CWallet::LoadWallet`, and fixing python test race condition.
Tree-SHA512: 029209e006de0240436817204e69e548c5665e2b0721b214510e7aba7eba130a5eab441d3a1ad95bd6426114dd27390492c77bf4560a9610009b32cd0a1f72f7
2457aea83c Assert that the HRP is lowercase in Bech32::Encode (Samuel Dobson)
Pull request description:
From BIP-173:
> The lowercase form is used when determining a character's value for checksum purposes.
> Encoders MUST always output an all lowercase Bech32 string. If an uppercase version of the encoding result is desired, (e.g.- for presentation purposes, or QR code use), then an uppercasing procedure can be performed external to the encoding process.
Currently if HRP contains uppercase characters, the checksum will be generated over these uppercase characters resulting in mixed-case output that will always be invalid even if the case is changed manually after encoding. This shouldn't happen because both prefix's `bc` and `tb` are lowercase currently, but we assert this condition anyway.
This is consistent also with the [C reference implementation](2b0aac650c/ref/c/segwit_addr.c (L59))
ACKs for top commit:
laanwj:
ACK 2457aea83c
Tree-SHA512: 24fcbbc2f315c72c550cc3d82b4332443eea6378fc73d571f98b87492604d023378dd102377c9e05467192cae6049606dee98e4c5688c8d5e4caac50c970284b
dcc448e3d2 Avoid unnecessary "Synchronizing blockheaders" log messages (Jonas Schnelli)
Pull request description:
Fixes#16773
I'm not entirely sure why 16773 happend, but probably due to headers fallback in a compact block.
However, this PR should fix it and should have been included in #15615.
ACKs for top commit:
ajtowns:
ACK dcc448e3d2 ; code review only, haven't compiled or tested.
promag:
ACK dcc448e3d2.
TheBlueMatt:
utACK dcc448e3d2. Went and read how pindexBestHeader is handled and this code looks correct (worst case it breaks a LogPrint, so whatever). I also ran into this on #16762.
fanquake:
ACK dcc448e3d2
Tree-SHA512: f8cac3b6eb9d4e8fab53a535b55f9ea9b058e3ab6ade64801ebc56439ede4f54b5fee36d5d2b316966ab987b65b13ab9dc18849f345d08b81ecdf2722a3f5f5a
fa61365a13 wallet: Translate all initErrors in CreateWalletFromFile (MarcoFalke)
fa70d199d0 util: Make util/error bilingual_str (refactor) (MarcoFalke)
Pull request description:
The translations are going to close in three days (#15940), so I am submitting this as a standalone pull request.
Those changes are part of a bugfix #16661, which includes a test. The first change (the refactor) is required, the second commit is not. I am happy to drop it, if needed.
ACKs for top commit:
laanwj:
utACK fa61365a13
hebasto:
ACK fa61365a13, I have tested the code on Linux Mint 19.2.
Tree-SHA512: a7616cc38b9ffd301c6b915ea808a65815c3d97e9f57ec091772eb260e5cf0d75a13a6e4dfa3913e236833677c7929b9a748cb7d7a0e406d51749944b614e11b
9965940e35 doc: Add release note for the new gettransaction argument (darosior)
b8b3f0435a tests: Add a new functional test for gettransaction (darosior)
7f3bb247a8 gettransaction: add an argument to decode the transaction (darosior)
Pull request description:
This PR adds a new parameter to the `gettransaction` call : `decode`. If set to `true`, it will add a new `decoded` field to the response. This mimics the behavior of `getrawtransaction`'s `verbose` argument to avoid using 2 calls if we want to decode a wallet transaction (`gettransaction` then `decoderawtransaction`).
Fix#16181 .
ACKs for top commit:
meshcollider:
re-utACK 9965940e35
Tree-SHA512: bcb6b4bd252b3488d6afc77659c499c2ad99fd58661eb24b6a2e17014c74f22e47fde70e00fedb4f4754915786622ad02483b2cf2c4dea0ab0eb4ac8276dbeee
9b92538ade Remove unused fScriptChecks parameter from CheckInputs (Matt Corallo)
Pull request description:
fScriptChecks = false just short-circuits the entire function, so
passing it in is entirely useless.
This is extracted from #13233 /cc TheBlueMatt.
Recommend reviewing with `git show --ignore-all-space`, i.e.:
https://github.com/bitcoin/bitcoin/pull/13868/files?w=1
ACKs for top commit:
TheBlueMatt:
utACK 9b92538ade. Checked diff had no functional change and new comment copy looks correct.
kallewoof:
ACK 9b92538ade
ajtowns:
ACK 9b92538ade ; code review, checked tests work. Looks right to me, and fanquake's notes make sense. Could change the coinbase early exit to `assert(!tx.IsCoinBase());`.
fanquake:
ACK 9b92538ade - Notes / testing below.
Tree-SHA512: add253a3e8cf4b33eddbc49efcec333c14b5ea61c7d34e43230351d40cff6adc919a75b91c72c4de8647a395284db74a61639f4c67848d4b2fec3a705b557790
0bb33b5348 qt: Replace objc_msgSend with native syntax (Hennadii Stepanov)
Pull request description:
Changes in Xcode 11 Objective-C Runtime cause an error (#16387) during building on MacOS 10.15 Catalina.
This PR fixes this issue by replacing `objc_msgSend()` function calls with the native Objective-C syntax.
Refs:
- [changes in `objc_msgSend` function](https://developer.apple.com/documentation/objectivec/1456712-objc_msgsend?changes=latest_minor&language=objc)
- [`OBJC_OLD_DISPATCH_PROTOTYPES` macro](https://developer.apple.com/documentation/objectivec/objc_old_dispatch_prototypes?language=objc)
ACKs for top commit:
l2a5b1:
ACK 0bb33b5 - Diff looks good. Sending messages via native Objective-C code feels more robust and is more readable than casting all the `objc_msgSend` function calls to the appropriate function signature (which would also have fixed the issue).
jonasschnelli:
utACK 0bb33b5348 - Confirmed that the called macOS framework function is available on our build targets.
fanquake:
ACK 0bb33b5348 - Still works as expected.
Tree-SHA512: c09cb684d06bd1da053a17c182b7bb1642e45bb347d26c76e1c5d835c320567caee366d85e34bb7f2be38e63ed041e0d06a56c2a9d89f7e5bece9b19cc5c6772
d9d8984270 wallet: Use wallet name instead of pointer on unload/release (João Barbosa)
Pull request description:
Fixes#16668. Wallet name is unique so it can be used instead of pointer.
ACKs for top commit:
meshcollider:
utACK d9d8984270
instagibbs:
utACK d9d8984270
ryanofsky:
utACK d9d8984270. Alternately I think it might be possible to use an intptr_t set instead of a string set to get around the undefined behavior described in the issue.
Tree-SHA512: eccd4d260cd4c02b52c30deeb32dbfd190a1151a5340eb3aa4ece0dc6ae3b3ed746ce5617336461f6f27c437c435629cd07d20beb1c5450f23b75edde6728598
This adds a new boolean parameter 'decode' to the gettransaction call, which, if set to true, add a 'decoded' field to the result containing the decoded transaction
8b6f5aabb9 qt: Replace QFontMetrics::width() with TextWidth() (Hennadii Stepanov)
Pull request description:
Compiling master (d8fc997913) on macOS Catalina (with a patch from #16720) reveals one more instance of `QFontMetrics::width()` which is supposed to be replaced with `TextWidth()` in the merged #16701.
Sorry for incomplete solution provided in #16701. It’s especially sad that the line I missed lies in only 7 lines from the code touched in #16701.
ACKs for top commit:
fanquake:
ACK 8b6f5aabb9
Tree-SHA512: 65cd8bea550150e5ee47c1e906d8c2393547cf4feba3701a933a4f24fad5ecdb552ac2de4e1200ed14efaa0df0480150dd58fccbddc3b902f6c2141603874902
798a589aff wallet: extract PubKey from P2PK script with Solver (Sebastian Falbesoner)
Pull request description:
The function `ExtractPubKey()` checks if a given script matches the P2PK pattern
(`<PubKey> OP_CHECKSIG`), extracts the PubKey and additionally checks if it is
cryptographically valid (full validation with ECC library via `CPubKey::IsFullyValid()`).
Currently this is done manually in the following order:
1. check if first script OP is data push with valid PubKey length (first part of pattern match), extract PubKey
2. create `CPubKey` object with extracted PubKey
3. fully validate public key
4. check if last script OP is `OP_CHECKSIG` (second part of pattern match)
Using Solver, the pattern matching and PubKey extraction can be done via a
single step, leading to the following simplified order with shorter code:
1. check if given script matches P2PK pattern with Solver (also contains valid PubKey length check), extracts Pubkey
2. create `CPubKey` object with extracted Pubkey
3. fully validate public key
ACKs for top commit:
instagibbs:
utACK 798a589aff
theStack:
> utACK [798a589](798a589aff)
sipa:
ACK 798a589aff
achow101:
Code Review ACK 798a589aff
Tree-SHA512: 350358a89afed8c2a7967c50e9714a2d4a909259b50e694ce68dde3e7d0fa0bf3238d33642e73f2bdb53860f6d3f7327ca3eb6426b74eaffacfbca0a384d68cd
fa0b910486 [doc] chain: Declare BLOCK_VALID_HEADER reserved (MarcoFalke)
Pull request description:
`BLOCK_VALID_HEADER` was never used and the comment is confusing to me in several ways:
* It claims "version ok". However, without the previous header, it is not possible to check the validity of the version since the height needs to be known (c.f. BIP 90)
* It claims "hash satisfies claimed PoW". While it is possible to check against the claimed PoW, it is not possible without the previous header to check that the claimed PoW is itself valid.
* It claims "1 <= vtx count <= max". However, with the header alone and current consensus rules, the number of transactions is unknown.
ACKs for top commit:
sipa:
ACK fa0b910486
ryanofsky:
ACK fa0b910486
Tree-SHA512: 3972995a0a2f83aa55767bf8982af1fcb9493483f62aee6df27e58be9181a48d5968ae718b390cecc8be3ed4f26495683b1cffde8ef272dea0bd610ec169ef8b
c53667764e qt: Remove obsolete QModelIndex::child() (Hennadii Stepanov)
Pull request description:
The `QModelIndex::child()` member function is [obsolete](https://doc.qt.io/qt-5.12/qmodelindex-obsolete.html) since Qt 5.12.
This PR removes it, does not change behavior and keeps compatibility with [Qt 5.5.1](https://github.com/bitcoin/bitcoin/pull/15393).
Here is an excerpt from the master build log:
```
qt/receivecoinsdialog.cpp: In member function ‘void ReceiveCoinsDialog::copyColumnToClipboard(int)’:
qt/receivecoinsdialog.cpp:264:111: warning: ‘QModelIndex QModelIndex::child(int, int) const’ is deprecated: Use QAbstractItemModel::index [-Wdeprecated-declarations]
GUIUtil::setClipboard(model->getRecentRequestsTableModel()->data(firstIndex.child(firstIndex.row(), column), Qt::EditRole).toString());
^
In file included from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qabstractitemview.h:45:0,
from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qheaderview.h:44,
from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/QHeaderView:1,
from ./qt/guiutil.h:12,
from ./qt/receivecoinsdialog.h:8,
from qt/receivecoinsdialog.cpp:7:
/home/hebasto/Qt/5.13.0/gcc_64/include/QtCore/qabstractitemmodel.h:457:20: note: declared here
inline QModelIndex QModelIndex::child(int arow, int acolumn) const
^~~~~~~~~~~
```
ACKs for top commit:
laanwj:
Code review ACK c53667764e
promag:
ACK c53667764e, just read the change.
jonasschnelli:
utACK c53667764e
Tree-SHA512: 99fcb6ff60a6d47b925bda9f14006269eaad09ba4f7a41ac4975c6cf04bd906b58aed721cbfa0be7da8e6613d92e30d4be18b7e4d3960f026c7226558a4c3196
Add a LockChain method to CWallet to know if we can lock or query
chain state safely.
At tx loading, we rely on chain to know if hashBlock of tx is still
in main chain. If not, we set its status to unconfirmed and reset
its hashBlock/nIndex.
If wallet loaded is the wallet-tool one, all wallet txn will
show up with a height of zero. It doesn't matter as status is not
used by wallet-tool.
We take lock prematurely in CWallet::LoadWallet and CWallet::Verify
to ensure that lock order is respected between cs_main an cs_wallet.
d48c1e837a Add window final block height to getchaintxstats (Jonathan "Duke" Leto)
Pull request description:
This patch is motivated by the desire to make the output of `getchaintxstats` more useful and optimized for applications to consume and render the data.
Firstly, this data is already available to the RPC, no additional work is done. Currently additional RPC calls will be needed to look up the height of the final block in the window or the block height that began the window.
By adding the block height of the final block in the window, the JSON is "self-contained" and applications can calculate the exact block height range of the window with no additional RPC requests.
For example, a web application which wants to render historical information for `getchaintxstats` RPC on various window sizes might call the RPC with various window lengths, once per day, and store the JSON results somewhere. Because the final block height of each dataset is included, it's no extra work to determine the exact block window range of each JSON response.
ACKs for top commit:
promag:
ACK d48c1e837a.
Tree-SHA512: fd4952c125f81a4ad18f7c78498c6b3e265b93cb574832166ac25596321ce84957f971f3f78f37d7e42638dc65f2a5d4d760f289873c9c2f2a82eb00a0f87c3f
0912134039 qt: Remove QSignalMapper from TransactionView (Hennadii Stepanov)
9e0c1d676c qt: Remove QSignalMapper from RPCConsole (Hennadii Stepanov)
Pull request description:
The [`QSignalMapper`](https://doc.qt.io/qt-5/qsignalmapper.html) class has been [deprecated](https://doc-snapshots.qt.io/qt5-5.10/obsoleteclasses.html) since Qt 5.10.
This PR replaces it by lambdas and does not change behavior.
ACKs for top commit:
jonasschnelli:
utACK 0912134039
Tree-SHA512: 0c102d5cab4adc8b6252f72e07123ac87c65434c88cada3e72816ecea8fc4803f15b9c050fb5e1c7e8a96f709265521fd6813ab1890dbf5634032f7ee0d50675
d75e704ac0 Add log output during initial header sync (Jonas Schnelli)
Pull request description:
The non debug log output is completely quiet during the header sync. I see two main reasons to add infos about the state of the initial header sync...
* users may think the node did fail to start sync
* it's a little complicate to check if your getting throttled during header sync (repeatedly calling `getchaintips` or similar)
ACKs for top commit:
fanquake:
Concept ACK d75e704ac0
practicalswift:
utACK d75e704ac0
laanwj:
Tested ACK d75e704ac0
Tree-SHA512: 2e738571b703d7251290864603c3a829729645962c2fa3187250bab0585e66a5f01fce892e9b5b98da451fab2b40a2e4784f9b2e5a9cad75ff62c535affe7430
c6dd32da69 qt: Replace obsolete functions of QDesktopWidget (Hennadii Stepanov)
1260ecd812 qt: Add TextWidth() wrapper (Hennadii Stepanov)
Pull request description:
The following functions are obsolete in Qt 5.13:
- [`QFontMetrics::width()`](https://doc.qt.io/qt-5/qfontmetrics-obsolete.html#width)
- [`QDesktopWidget::availableGeometry()`](https://doc.qt.io/qt-5/qdesktopwidget-obsolete.html#availableGeometry)
- [`QDesktopWidget::screenGeometry()`](https://doc.qt.io/qt-5/qdesktopwidget-obsolete.html#screenGeometry)
This PR replaces them and does not change behavior.
Here are some excerpts from the master build log:
```
qt/bitcoingui.cpp: In constructor ‘BitcoinGUI::BitcoinGUI(interfaces::Node&, const PlatformStyle*, const NetworkStyle*, QWidget*)’:
qt/bitcoingui.cpp:84:57: warning: ‘const QRect QDesktopWidget::availableGeometry(int) const’ is deprecated: Use QGuiApplication::screens() [-Wdeprecated-declarations]
move(QApplication::desktop()->availableGeometry().center() - frameGeometry().center());
^
In file included from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/QDesktopWidget:1:0,
from qt/bitcoingui.cpp:43:
/home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qdesktopwidget.h:88:67: note: declared here
QT_DEPRECATED_X("Use QGuiApplication::screens()") const QRect availableGeometry(int screen = -1) const;
^~~~~~~~~~~~~~~~~
```
```
qt/bitcoingui.cpp:1410:74: warning: ‘int QFontMetrics::width(const QString&, int) const’ is deprecated: Use QFontMetrics::horizontalAdvance [-Wdeprecated-declarations]
max_width = qMax(max_width, fm.width(BitcoinUnits::longName(unit)));
^
In file included from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qwidget.h:50:0,
from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qdialog.h:44,
from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/QDialog:1,
from ./qt/optionsdialog.h:8,
from ./qt/bitcoingui.h:12,
from qt/bitcoingui.cpp:5:
/home/hebasto/Qt/5.13.0/gcc_64/include/QtGui/qfontmetrics.h:108:9: note: declared here
int width(const QString &, int len = -1) const;
^~~~~
```
```
qt/splashscreen.cpp: In constructor ‘SplashScreen::SplashScreen(interfaces::Node&, Qt::WindowFlags, const NetworkStyle*)’:
qt/splashscreen.cpp:127:50: warning: ‘const QRect QDesktopWidget::screenGeometry(int) const’ is deprecated: Use QGuiApplication::screens() [-Wdeprecated-declarations]
move(QApplication::desktop()->screenGeometry().center() - r.center());
^
In file included from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/QDesktopWidget:1:0,
from qt/splashscreen.cpp:24:
/home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qdesktopwidget.h:79:67: note: declared here
QT_DEPRECATED_X("Use QGuiApplication::screens()") const QRect screenGeometry(int screen = -1) const;
^~~~~~~~~~~~~~
```
ACKs for top commit:
jonasschnelli:
utACK c6dd32da69
Tree-SHA512: deb7bcbf86e1dcc6508bd91288772c2fe8811db79fa2011de37d0469cdd094fbf7fd8c4512c607bed0bd08dc2968e893c0bbc190732c43c69ed1085259df766c
The function ExtractPubKey() checks if a given script matches the P2PK pattern
(<PubKey> OP_CHECKSIG), extracts the PubKey and additionally checks if it is
cryptographically valid (full validation with ECC library via .IsFullyValid()).
Currently this is done manually in the following order:
1) check if first script OP is data push with valid PubKey length
(first part of pattern match), extract PubKey
2) create CPubKey object with extracted PubKey
3) fully validate public key
4) check if last script OP is OP_CHECKSIG
(second part of pattern match)
Using Solver, the pattern matching and PubKey extraction can be done via a
single step, leading to the following simplified order with shorter code:
1) check if given script matches P2PK pattern with Solver
(also contains valid PubKey length check), extracts Pubkey
2) create CPubKey object with extracted Pubkey
3) fully validate public key
41d484d5c8 doc: Delete stale URL in test README (Michael Folkson)
Pull request description:
The resource on the Boost unit test framework previously linked to in src/test/README.md was a stale URL.
Instead of deleting it, I've replaced it with an alternative resource on the framework on [boost.org](https://www.boost.org/doc/libs/1_45_0/libs/test/doc/html/utf/tutorials.html).
ACKs for top commit:
promag:
ACK 41d484d5c8.
hebasto:
ACK 41d484d5c8, the removed link is really obsolete.
fanquake:
ACK 41d484d5c8 - Thanks.
Tree-SHA512: 764f12548441bde615f77b7a2ca7c5188b4ab936972d16b84960fbd8604d4cbd224415bc59ce839e7e63293aa84fd97f31a69e38734e531231cdb0e148d2e1bd
Translated strings should not end up in the debug log, stderr, or
returned by an RPC.
Changing the util methods in util/error to return a bilingual_str paves
the way to achieve this goal in the long term.
8a3b2eb175 move-only: move coins statistics utils out of RPC (James O'Beirne)
Pull request description:
This is part of the [assumeutxo project](https://github.com/bitcoin/bitcoin/projects/11):
Parent PR: #15606
Issue: #15605
Specification: https://github.com/jamesob/assumeutxo-docs/tree/master/proposal
---
In the short-term, this move-only commit will help with fuzzing (https://github.com/bitcoin/bitcoin/pull/15606#issuecomment-524482297). Later, these procedures will be used to compute statistics (particularly a content hash) for UTXO sets coming in from snapshots.
Most easily reviewed with `git ... --color-moved=dimmed_zebra`. A nice follow-up would be adding unittests, which I'll do if nobody else gets around to it.
ACKs for top commit:
MarcoFalke:
ACK 8a3b2eb175, checked --color-moved=dimmed-zebra
Tree-SHA512: a187d2f7590ad2450b8e8fa3d038c80a04fc3d903618c24222d7e3172250ce51badea35860c86101f2ba266eb4354e6efb8d7d508b353f29276e4665a1efdf74
These procedures will later be used in the ChainstateManager to compute
statistics (particularly a content hash) for UTXO sets coming in from
snapshots.
We shouldn't rely on this sync call to get an accurate view of txn
state, if a tx conflicts with one in mapTx we are going to update
our wallet dependencies in AddToWalletIfInvolvingMe while conflicting
txn get connected. If it doesn't conflict with one of our dependencies
we are not going to track it anyway.
This is a cleanup, as this SyncTransaction is redundant with the
following one for confirmation which is triggering the MarkConflicted
logic. We keep the loop because set of conflicted txn isn't same as txn
included in block.
Instead of relying on combination of hashBlock and nIndex
values to manage tx in its lifecycle, we introduce 4
status : CONFIRMED, UNCONFIRMED, CONFLICTED, ABANDONED.
hashBlock and nIndex magic values should only be used at
serialization/deserialization for backward-compatibility.
At block disconnection, we know flag txn as UNCONFIRMED where
previously they kept their states until being override by a
block connection or abandontransaction call. This is a change
in behavior for which user may have to call abandon twice
if transaction is disconnected and not accepted back in the mempool.
We assert status transitioning right in AddToWallet. Doing so
flagged a misbehavior in ComputeTimeSmart unit test where same
tx is confirmed twice in different block. To avoid inconsistencies
we unconfirmed tx before new connection in different block. We
also remove a cs_main lock in test, as AddToWallet and its
callees don't rely on locked chain.
In Qt 5.12 and before the QFontMetrics::width() is used and it is
deprecated since Qt 13.0.
In Qt 5.11 the QFontMetrics::horizontalAdvance() was introduced.
