Add QStandardPaths::findExecutable.

Change-Id: If30a83622e2ac5af48e47a38b8f70fce73044d74
Reviewed-by: Thiago Macieira (Intel) <thiago.macieira@intel.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/src/corelib/io/qstandardpaths.cpp b/src/corelib/io/qstandardpaths.cpp
index 58a6ab13eb..86d0f7424d 100644
--- a/src/corelib/io/qstandardpaths.cpp
+++ b/src/corelib/io/qstandardpaths.cpp
@@ -176,6 +176,93 @@ QStringList QStandardPaths::locateAll(StandardLocation type, const QString &file
     return result;
 }
 
+#ifdef Q_OS_WIN
+static QStringList executableExtensions()
+{
+    QStringList ret = QString::fromLocal8Bit(qgetenv("PATHEXT")).split(QLatin1Char(';'));
+    if (!ret.contains(QLatin1String(".exe"), Qt::CaseInsensitive)) {
+        // If %PATHEXT% does not contain .exe, it is either empty, malformed, or distorted in ways that we cannot support, anyway.
+        ret.clear();
+        ret << QLatin1String(".exe")
+            << QLatin1String(".com")
+            << QLatin1String(".bat")
+            << QLatin1String(".cmd");
+    }
+    return ret;
+}
+#endif
+
+static QString checkExecutable(const QString &path)
+{
+    const QFileInfo info(path);
+    if (info.isBundle())
+        return info.bundleName();
+    if (info.isFile() && info.isExecutable())
+        return QDir::cleanPath(path);
+    return QString();
+}
+
+/*!
+  Finds the executable named \a executableName in the paths specified by \a paths,
+  or the system paths if \a paths is empty.
+
+  On most operating systems the system path is determined by the PATH environment variable.
+
+  The directories where to search for the executable can be set in the \a paths argument.
+  To search in both your own paths and the system paths, call findExecutable twice, once with
+  \a paths set and once with \a paths empty.
+
+  Symlinks are not resolved, in order to preserve behavior for the case of executables
+  whose behavior depends on the name they are invoked with.
+
+  \note On Windows, the usual executable extensions (from the PATHEXT environment variable)
+  are automatically appended, so that for instance findExecutable("foo") will find foo.exe
+  or foo.bat if present.
+
+  Returns the absolute file path to the executable, or an empty string if not found.
+ */
+QString QStandardPaths::findExecutable(const QString &executableName, const QStringList &paths)
+{
+    if (QFileInfo(executableName).isAbsolute())
+        return checkExecutable(executableName);
+
+    QStringList searchPaths = paths;
+    if (paths.isEmpty()) {
+        QByteArray pEnv = qgetenv("PATH");
+#if defined(Q_OS_WIN) || defined(Q_OS_SYMBIAN)
+        const QLatin1Char pathSep(';');
+#else
+        const QLatin1Char pathSep(':');
+#endif
+        searchPaths = QString::fromLocal8Bit(pEnv.constData()).split(pathSep, QString::SkipEmptyParts);
+    }
+
+    QDir currentDir = QDir::current();
+    QString absPath;
+#ifdef Q_OS_WIN
+    static QStringList executable_extensions = executableExtensions();
+#endif
+
+    for (QStringList::const_iterator p = searchPaths.constBegin(); p != searchPaths.constEnd(); ++p) {
+        const QString candidate = currentDir.absoluteFilePath(*p + QLatin1Char('/') + executableName);
+#ifdef Q_OS_WIN
+        const QString extension = QLatin1Char('.') + QFileInfo(executableName).suffix();
+        if (!executable_extensions.contains(extension, Qt::CaseInsensitive)) {
+            foreach (const QString &extension, executable_extensions) {
+                absPath = checkExecutable(candidate + extension.toLower());
+                if (!absPath.isEmpty())
+                    break;
+            }
+        }
+#endif
+        absPath = checkExecutable(candidate);
+        if (!absPath.isEmpty()) {
+            break;
+        }
+    }
+    return absPath;
+}
+
 /*!
     \fn QString QStandardPaths::displayName(StandardLocation type)