Deduplicate consistsOfWhitespace()

Optimize ILanguageSupport::suggestedReparseDelayForChange() along the
way by not checking the `joinedWord` condition if the change contains
non-whitespace characters.

Simply remove unused CodeCompletionContext::containsOnlySpaces().

kdevplatform/language/duchain/stringhelpers.cpp

@@ -10,6 +10,8 @@
 #include <QString>
 #include <QVarLengthArray>
 
+#include <algorithm>
+
 namespace {
 bool endsWithWordBoundary(QStringView str)
 {
@@ -105,6 +107,13 @@ int skipComment(QStringView str, int pos)
 } // unnamed namespace
 
 namespace KDevelop {
+bool consistsOfWhitespace(QStringView str)
+{
+    return std::all_of(str.cbegin(), str.cend(), [](QChar c) {
+        return c.isSpace();
+    });
+}
+
 class ParamIteratorPrivate
 {
     Q_DISABLE_COPY_MOVE(ParamIteratorPrivate)

kdevplatform/language/duchain/stringhelpers.h

@@ -19,6 +19,11 @@ class QStringView;
 namespace KDevelop {
 class ParamIteratorPrivate;
 
+/**
+ * @return true if QChar::isSpace() returns true for all elements of @p str.
+ */
+bool KDEVPLATFORMLANGUAGE_EXPORT consistsOfWhitespace(QStringView str);
+
 /**
  * Searches a fitting closing brace from left to right: a ')' for '(', ']' for '[', ...
  */

kdevplatform/language/interfaces/ilanguagesupport.cpp

@@ -7,6 +7,7 @@
 
 #include "ilanguagesupport.h"
 #include "../duchain/duchain.h"
+#include "../duchain/stringhelpers.h"
 
 #include <QReadWriteLock>
 
@@ -93,13 +94,9 @@ int ILanguageSupport::suggestedReparseDelayForChange(KTextEditor::Document* doc,
                                                      const KTextEditor::Range& changedRange,
                                                      const QString& /*removedText*/, bool /*removal*/) const
 {
-    auto text = doc->text(changedRange);
-    bool joinedWord = doc->wordRangeAt(changedRange.start()).isEmpty() ||
-                      doc->wordRangeAt(changedRange.end()).isEmpty();
-
-    auto isWhitespace = std::all_of(text.begin(), text.end(), [](const QChar& c) {
-            return c.isSpace();
-        });
-    return (isWhitespace && !joinedWord) ? NoUpdateRequired : DefaultDelay;
+    const auto joinedWord = [doc, &changedRange] {
+        return doc->wordRangeAt(changedRange.start()).isEmpty() || doc->wordRangeAt(changedRange.end()).isEmpty();
+    };
+    return consistsOfWhitespace(doc->text(changedRange)) && !joinedWord() ? NoUpdateRequired : DefaultDelay;
 }
 }

plugins/clang/codecompletion/model.cpp

@@ -18,6 +18,7 @@
 #include <language/duchain/topducontext.h>
 #include <language/duchain/duchainutils.h>
 #include <language/duchain/duchainlock.h>
+#include <language/duchain/stringhelpers.h>
 
 #include <KTextEditor/View>
 #include <KTextEditor/Document>
@@ -28,11 +29,6 @@ using namespace KDevelop;
 
 namespace {
 
-bool isSpaceOnly(const QString& string)
-{
-    return std::find_if(string.begin(), string.end(), [] (const QChar c) { return !c.isSpace(); }) == string.end();
-}
-
 bool includePathCompletionRequired(const QString& text)
 {
     const auto properties = IncludePathProperties::parseText(text);
@@ -173,7 +169,7 @@ bool ClangCodeCompletionModel::shouldStartCompletion(KTextEditor::View* view, co
 {
     const QString noCompletionAfter = QStringLiteral(";{}]) ");
 
-    if (inserted.isEmpty() || isSpaceOnly(inserted)) {
+    if (inserted.isEmpty() || consistsOfWhitespace(inserted)) {
         return false;
     }
     const auto lastChar = inserted.at(inserted.size() - 1);

plugins/qmljs/codecompletion/context.cpp

@@ -491,12 +491,4 @@ DeclarationPointer CodeCompletionContext::declarationAtEndOfString(const QString
 
     return visitor.lastDeclaration();
 }
-
-bool CodeCompletionContext::containsOnlySpaces(const QString& str)
-{
-    return std::all_of(str.begin(), str.end(), [](const QChar c) {
-        return c.isSpace();
-    });
-}
-
 }

plugins/qmljs/codecompletion/context.h

@@ -81,7 +81,6 @@ private:
 
     KDevelop::Stack<ExpressionStackEntry> expressionStack(const QString& expression);    /*!< @see ExpressionStackEntry */
     KDevelop::DeclarationPointer declarationAtEndOfString(const QString& expression);
-    bool containsOnlySpaces(const QString &str);
 
 private:
     enum CompletionKind {