QUuid: add fromString(QStringView/QLatin1String)

As for the formatting code, de-duplicate the parsing code by only
parsing char*s, converting QChars to Latin-1 first in a small buffer.

The QUuid(const char*) ctor performed no length checking, relying
instead on the checks performed within _q_uuidFromHex(), which
includes an implicit check for premature end (because NUL is not
a valid token for the parser).

The (QString) and (QByteArray) ctors did perform length checking.
To the extent possible, this is removed, since it is handled by
_q_uuidFromHex(). Failure cases need not be optimized. Only the
QLatin1String overload needs to do some checking, because views in
general are not NUL-terminated. The QStringView overload can just
append a NUL when it converts to Latin-1.

The only check I added to _q_uuidFromHex() is that for src ==
nullptr. It would otherwise be duplicated in several callers.

While touching the internal functions, port to passing and returning
by value.

Saves 1.6KiB in text size on optimized GCC 6.1 Linux AMD64 builds,
even though we added new API.

Port some users to the new functions. Expand fromString() test.

[ChangeLog][QtCore][QUuid] Added fromString(QStringView/QLatin1String).

Change-Id: I519339419129550c86e0ea80514865cd6a768f5d
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 50 insertions, 6 deletions

diff --git a/tests/auto/corelib/plugin/quuid/tst_quuid.cpp b/tests/auto/corelib/plugin/quuid/tst_quuid.cpp
index d3102c7ee5..9e3edc96ec 100644
--- a/tests/auto/corelib/plugin/quuid/tst_quuid.cpp
+++ b/tests/auto/corelib/plugin/quuid/tst_quuid.cpp
@@ -41,6 +41,7 @@ private slots:
 
     void fromChar();
     void toString();
+    void fromString_data();
     void fromString();
     void toByteArray();
     void fromByteArray();
@@ -127,15 +128,58 @@ void tst_QUuid::toString()
     QCOMPARE(uuidB.toString(), QString("{1ab6e93a-b1cb-4a87-ba47-ec7e99039a7b}"));
 }
 
+void tst_QUuid::fromString_data()
+{
+    QTest::addColumn<QUuid>("expected");
+    QTest::addColumn<QString>("input");
+
+    QUuid invalid = {};
+
+#define ROW(which, string) \
+    QTest::addRow("%-38s -> %s", string, #which) << which << string
+    ROW(uuidA,   "{fc69b59e-cc34-4436-a43c-ee95d128b8c5}");
+    ROW(uuidA,    "fc69b59e-cc34-4436-a43c-ee95d128b8c5}");
+    ROW(uuidA,   "{fc69b59e-cc34-4436-a43c-ee95d128b8c5" );
+    ROW(uuidA,    "fc69b59e-cc34-4436-a43c-ee95d128b8c5" );
+
+    ROW(uuidA,   "{fc69b59e-cc34-4436-a43c-ee95d128b8c56"); // too long (not an error!)
+    ROW(invalid, "{fc69b59e-cc34-4436-a43c-ee95d128b8c"  ); // premature end (within length limits)
+    ROW(invalid, " fc69b59e-cc34-4436-a43c-ee95d128b8c5}"); // leading space
+    ROW(uuidA,   "{fc69b59e-cc34-4436-a43c-ee95d128b8c5 "); // trailing space (not an error!)
+    ROW(invalid, "{gc69b59e-cc34-4436-a43c-ee95d128b8c5}"); // non-hex digit in 1st group
+    ROW(invalid, "{fc69b59e-cp34-4436-a43c-ee95d128b8c5}"); // non-hex digit in 2nd group
+    ROW(invalid, "{fc69b59e-cc34-44r6-a43c-ee95d128b8c5}"); // non-hex digit in 3rd group
+    ROW(invalid, "{fc69b59e-cc34-4436-a4yc-ee95d128b8c5}"); // non-hex digit in 4th group
+    ROW(invalid, "{fc69b59e-cc34-4436-a43c-ee95d128j8c5}"); // non-hex digit in last group
+    ROW(invalid, "(fc69b59e-cc34-4436-a43c-ee95d128b8c5}"); // wrong initial character
+    ROW(invalid, "{fc69b59e+cc34-4436-a43c-ee95d128b8c5}"); // wrong 1st separator
+    ROW(invalid, "{fc69b59e-cc34*4436-a43c-ee95d128b8c5}"); // wrong 2nd separator
+    ROW(invalid, "{fc69b59e-cc34-44366a43c-ee95d128b8c5}"); // wrong 3rd separator
+    ROW(invalid, "{fc69b59e-cc34-4436-a43c\303\244ee95d128b8c5}"); // wrong 4th separator (&auml;)
+    ROW(uuidA,   "{fc69b59e-cc34-4436-a43c-ee95d128b8c5)"); // wrong final character (not an error!)
+
+    ROW(uuidB,   "{1ab6e93a-b1cb-4a87-ba47-ec7e99039a7b}");
+#undef ROW
+}
+
 void tst_QUuid::fromString()
 {
-    QCOMPARE(uuidA, QUuid(QString("{fc69b59e-cc34-4436-a43c-ee95d128b8c5}")));
-    QCOMPARE(uuidA, QUuid(QString("fc69b59e-cc34-4436-a43c-ee95d128b8c5}")));
-    QCOMPARE(uuidA, QUuid(QString("{fc69b59e-cc34-4436-a43c-ee95d128b8c5")));
-    QCOMPARE(uuidA, QUuid(QString("fc69b59e-cc34-4436-a43c-ee95d128b8c5")));
-    QCOMPARE(QUuid(), QUuid(QString("{fc69b59e-cc34-4436-a43c-ee95d128b8c")));
+    QFETCH(const QUuid, expected);
+    QFETCH(const QString, input);
 
-    QCOMPARE(uuidB, QUuid(QString("{1ab6e93a-b1cb-4a87-ba47-ec7e99039a7b}")));
+    const auto inputL1 = input.toLatin1();
+    const auto inputU8 = input.toUtf8();
+
+    QCOMPARE(expected, QUuid(input));
+    QCOMPARE(expected, QUuid(inputU8));
+    QCOMPARE(expected, QUuid(inputL1));
+
+    QCOMPARE(expected, QUuid::fromString(input));
+
+    // for QLatin1String, construct one whose data() is not NUL-terminated:
+    const auto longerInputL1 = inputL1 + '5'; // the '5' makes the premature end check incorrectly succeed
+    const auto inputL1S = QLatin1String(longerInputL1.data(), inputL1.size());
+    QCOMPARE(expected, QUuid::fromString(inputL1S));
 }
 
 void tst_QUuid::toByteArray()