Some crypto libraries (like CyaSSL, MatrixSSL and CommonCrypto) either
don't have or expose this functionality at all, expose only part of it,
or (like OpenSSL) have heavyweight API for it. Also, for the task as
easy as BASE64 encoding and decoding it's much better to use small and
simple specialized library.
Prefer C++-style over C-style type casting.
Use qApp instead of QApplication/QCoreApplication::instance().
Use explicit QString::fromLatin1()/fromUtf8() where applicable.
Sync translations with the code. Adjust translations for changed phrases
(hopefully correct for the most of them).
One phrase still left untouched (Preferences -> Downloading), need to
think on better wording.
Among other things,
* fix turtle icons size (20x14 -> 16x16)
* use QIcon states instead of changing the turtle icon ourselves each
time (unchecked - off, checked - on)
* make speed limit action in tray menu checkable
* simplify status bar buttons drawing and use QToolButton instead of
QPushButton
Make squeeze labels (used for values on Information tab) display tooltip
on hover if their text doesn't fit. Make selective labels (same as in
GTK+ client) text selectable with keyboard in addition to mouse.
Prevent dialog width growth occured before to fit long error texts.
Add previously missing -Wall to warning flags in CMake. Remove -Wformat
and -Wvariadic-macros (enabled by default; latter is not meaningful in
C99 mode we use), -Wdeclaration-after-statement (again, not needed as
we use C99). Move -Wmissing-declarations to C-only flags (GCC man says
so).
Add copyrights year to crypto-utils-fallback.c.
On a way to factoring out OpenSSL support to a standalone file to ease
addition of other crypto libraries support in the future, move helpers
providing BASE64 encoding and decoding to crypto-utils.{c,h}. OpenSSL-
related functionality is moved to crypto-utils-openssl.c.
Add new functions to be implemented by crypto backends:
* tr_base64_encode_impl - encode from binary to BASE64,
* tr_base64_decode_impl - decode from BASE64 to binary.
Change `tr_base64_encode` and `tr_base64_decode` functions to expect
non-negative input data length which is considered real and never adjusted.
To process null-terminated strings (which was achieved before by passing 0
or -1 as input data length), add new `tr_base64_encode_str` and
`tr_base64_decode_str` functions which do not accept input data length as
an argument but calculate it on their own.
Doing otherwise causes Qt warning "QDBusConnection: session D-Bus
connection created before QCoreApplication. Application may misbehave."
Also, don't try to do anything D-Bus-related if connection fails.
