QUrl: update our understanding of the encoding of delimiters

The longer explanation can be found in the comment in qurl.cpp. The
short version is as follows:

Up to now, we considered that every character could be replaced with
its percent-encoding equivalent and vice-versa, so long as the parsing
of the URL did not change. For example, x:/path+path and
x:/path%2Bpath were the same. However, to do this and yet be compliant
with most URL uses in the real world, we had to add exceptions:
 - "/" and "%2F" were not the same in the path, despite the delimiter
   being behind (rationale was the complex definition of path)
 - "+" and "%2B" were not the same in the query, so we ended up not
   transforming any sub-delim in the query at all

Now, we change our understanding based on the following line from
RFC 3986 section 2.2:
   URIs that differ in the replacement of a reserved character with
   its corresponding percent-encoded octet are not equivalent.

From now on, QUrl will not replace any sub-delim or gen-delim
("reserved character"), except where such a character could not exist
in the first place. This simplifies the code and removes all
exceptions.

As a side-effect, this has also changed the behaviour of the "{" and
"}" characters, which we previously allowed to remain decoded.

[ChangeLog][Important Behavior Changes][QUrl and QUrlQuery] QUrl no
longer considers all delimiter characters equivalent to their
percent-encoded forms. Now, both classes always keep all delimiters
exactly as they were in the original URL text.

[ChangeLog][Important Behavior Changes][QUrl and QUrlQuery] QUrl no
longer decodes %7B and %7D to "{" and "}" in the output of toString()

Task-number: QTBUG-31660
Change-Id: Iba0b5b31b269635ac2d0adb2bb0dfb74c139e08c
Reviewed-by: David Faure (KDE) <faure@kde.org>

1 files changed, 0 insertions, 57 deletions

diff --git a/src/corelib/io/qurlrecode.cpp b/src/corelib/io/qurlrecode.cpp
index 509a92d2b0..9189cd294f 100644
--- a/src/corelib/io/qurlrecode.cpp
+++ b/src/corelib/io/qurlrecode.cpp
@@ -113,59 +113,6 @@ static const uchar defaultActionTable[96] = {
 // 0x00 if it belongs to this category
 // 0xff if it doesn't
 
-static const uchar delimsMask[96] = {
-    0xff, // space
-    0x00, // '!' (sub-delim)
-    0xff, // '"'
-    0x00, // '#' (gen-delim)
-    0x00, // '$' (gen-delim)
-    0xff, // '%' (percent)
-    0x00, // '&' (gen-delim)
-    0x00, // "'" (sub-delim)
-    0x00, // '(' (sub-delim)
-    0x00, // ')' (sub-delim)
-    0x00, // '*' (sub-delim)
-    0x00, // '+' (sub-delim)
-    0x00, // ',' (sub-delim)
-    0xff, // '-' (unreserved)
-    0xff, // '.' (unreserved)
-    0x00, // '/' (gen-delim)
-
-    0xff, 0xff, 0xff, 0xff, 0xff,  // '0' to '4' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // '5' to '9' (unreserved)
-    0x00, // ':' (gen-delim)
-    0x00, // ';' (sub-delim)
-    0xff, // '<'
-    0x00, // '=' (sub-delim)
-    0xff, // '>'
-    0x00, // '?' (gen-delim)
-
-    0x00, // '@' (gen-delim)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'A' to 'E' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'F' to 'J' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'K' to 'O' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'P' to 'T' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'U' to 'Z' (unreserved)
-    0x00, // '[' (gen-delim)
-    0xff, // '\'
-    0x00, // ']' (gen-delim)
-    0xff, // '^'
-    0xff, // '_' (unreserved)
-
-    0xff, // '`'
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'a' to 'e' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'f' to 'j' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'k' to 'o' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff,  // 'p' to 't' (unreserved)
-    0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'u' to 'z' (unreserved)
-    0xff, // '{'
-    0xff, // '|'
-    0xff, // '}'
-    0xff, // '~' (unreserved)
-
-    0xff  // BSKP
-};
-
 static const uchar reservedMask[96] = {
     0xff, // space
     0xff, // '!' (sub-delim)
@@ -617,8 +564,6 @@ static void maskTable(uchar (&table)[N], const uchar (&mask)[N])
 
     The \a encoding option modifies the default behaviour:
     \list
-    \li QUrl::EncodeDelimiters: if set, delimiters will be left untransformed (note: not encoded!);
-                                if unset, delimiters will be decoded
     \li QUrl::DecodeReserved: if set, reserved characters will be decoded;
                               if unset, reserved characters will be encoded
     \li QUrl::EncodeSpaces: if set, spaces will be encoded to "%20"; if unset, they will be " "
@@ -664,8 +609,6 @@ qt_urlRecode(QString &appendTo, const QChar *begin, const QChar *end,
         actionTable[0x7F - ' '] = EncodeCharacter;
     } else {
         memcpy(actionTable, defaultActionTable, sizeof actionTable);
-        if (!(encoding & QUrl::EncodeDelimiters))
-            maskTable(actionTable, delimsMask);
         if (encoding & QUrl::DecodeReserved)
             maskTable(actionTable, reservedMask);
         if (!(encoding & QUrl::EncodeSpaces))