qdoc: Clean up code related to processing of \include'd lines

* Use qsizetype instead of int.
* Remove unnecessary variable 'startLine'.
* Replace a while loop with a for loop.
* Replace nested conditional statements with (A && B).
* Fix a corner case where a lone snippet tag at the last line of
  included file caused out-of-bounds access of the line buffer.

Change-Id: I0b1009cf122681bcf700b67040a3d0ca19e82378
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
(cherry picked from commit f5a950df40295248b5da5aec261b2eb309033e25)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 14 insertions, 20 deletions

diff --git a/src/qdoc/docparser.cpp b/src/qdoc/docparser.cpp
index dc7b4a61f..0ca616577 100644
--- a/src/qdoc/docparser.cpp
+++ b/src/qdoc/docparser.cpp
@@ -1348,38 +1348,32 @@ void DocParser::include(const QString &fileName, const QString &identifier, cons
                 m_openedInputs.push(m_position + includedContent.size());
             } else {
                 QStringList lineBuffer = includedContent.split(QLatin1Char('\n'));
-                int i = 0;
-                int startLine = -1;
+                qsizetype bufLen{lineBuffer.size()};
+                qsizetype i;
                 QStringView trimmedLine;
-                while (i < lineBuffer.size()) {
+                for (i = 0; i < bufLen; ++i) {
                     trimmedLine = QStringView{lineBuffer[i]}.trimmed();
-                    if (trimmedLine.startsWith(QLatin1String("//!"))) {
-                        if (trimmedLine.contains(identifier)) {
-                            startLine = i + 1;
-                            break;
-                        }
-                    }
-                    ++i;
+                    if (trimmedLine.startsWith(QLatin1String("//!")) &&
+                        trimmedLine.contains(identifier))
+                        break;
                 }
-                if (startLine < 0) {
+                if (i < bufLen - 1) {
+                    ++i;
+                } else {
                     location().warning(
                             QStringLiteral("Cannot find '%1' in '%2'").arg(identifier, filePath));
                     return;
                 }
                 QString result;
-                i = startLine;
                 do {
                     trimmedLine = QStringView{lineBuffer[i]}.trimmed();
-                    if (trimmedLine.startsWith(QLatin1String("//!"))) {
-                        if (i < lineBuffer.size()) {
-                            if (trimmedLine.contains(identifier)) {
-                                break;
-                            }
-                        }
-                    } else
+                    if (trimmedLine.startsWith(QLatin1String("//!")) &&
+                        trimmedLine.contains(identifier))
+                        break;
+                    else
                         result += lineBuffer[i] + QLatin1Char('\n');
                     ++i;
-                } while (i < lineBuffer.size());
+                } while (i < bufLen);
 
                 expandArgumentsInString(result, parameters);
                 if (result.isEmpty()) {