Added support for ccache.

qbs/imports/VApp.qbs

@@ -24,10 +24,16 @@ CppApplication {
     installDebugInformation: true
     type: base.concat("testSuit")
 
+    Properties {
+        condition: qbs.targetOS.contains("unix") && buildconfig.buildWithCcache
+        cpp.compilerWrapper: "ccache"
+    }
+
     Properties {
         condition: Qt.core.versionMajor >= 5 &&  Qt.core.versionMinor < 12
         cpp.cxxLanguageVersion: "c++11"
     }
+
     // Since Qt 5.12 available support for C++17
     Properties {
         condition: Qt.core.versionMajor >= 5 &&  Qt.core.versionMinor >= 12

qbs/imports/VLib.qbs

@@ -19,6 +19,11 @@ Library {
         cpp.rpaths: cpp.rpathOrigin
     }
 
+    Properties {
+        condition: qbs.targetOS.contains("unix") && buildconfig.buildWithCcache
+        cpp.compilerWrapper: "ccache"
+    }
+
     install: !buildconfig.staticBuild
     installDir: buildconfig.installLibraryPath
     installDebugInformation: !buildconfig.staticBuild

qbs/modules/buildconfig/buildconfig.qbs

@@ -20,6 +20,14 @@ Module {
     // distributions which provides not enough space on build servers.
     property bool enablePCH: true
 
+    Depends { name: "ccache"; }
+
+    // Use this property to disable the use of ccache.
+    property bool enableCcache: true
+    readonly property bool ccachePresent: ccache.ccachePresent
+    readonly property bool ccachePCHSupport: ccache.pchSupport
+    readonly property bool buildWithCcache: enableCcache && (enablePCH && ccachePresent && ccachePCHSupport || (!enablePCH && ccachePresent))
+
     property string libDirName: "lib"
 
     property string appTarget

qbs/modules/ccache/ccache.qbs

@@ -0,0 +1,65 @@
+import qbs.Process
+import qbs.Utilities
+
+// Don't forget to edit ccache config:
+// ccache --set-config=sloppiness=pch_defines,time_macros,include_file_mtime,include_file_ctime
+Module {
+    readonly property bool ccachePresent: ccacheProbe.present
+    readonly property bool pchSupport: ccachePCHProbe.pchSupport
+
+    // change to shell tool which supports key "-c" to excecute command line
+    property string shellTool: "bash"
+
+    // ccache doesn't provide key to get only version number
+    readonly property string command: "ccache --version | head -n 1 | grep -oE '[0-9]((\.)[0-9]){0,2}'"
+
+    Probe {
+        id: ccacheProbe
+
+        property bool present
+        property string tool: shellTool
+        property string toolCommand: command
+
+        configure: {
+            var detector = new Process();
+            try {
+                if (detector.exec(tool, ["-c", toolCommand]) === 0) {
+                    var version = detector.readStdOut().trim(); // we can read only one time
+                    present = Utilities.versionCompare(version, "0.0.0") >= 0;
+                    console.info("Found ccache version " + version + ".");
+                }
+            } finally {
+                detector.close();
+            }
+        }
+    }
+
+    Probe {
+        id: ccachePCHProbe
+        condition: ccachePresent === true
+        property string tool: shellTool
+        property string toolCommand: command
+
+        property bool pchSupport
+
+        configure: {
+            var detector = new Process();
+            try {
+                if (detector.exec(tool, ["-c", toolCommand]) === 0) {
+                    var version = detector.readStdOut().trim(); // we can read only one time
+
+                    pchSupport = Utilities.versionCompare(version, "3.1.0") >= 0;
+                    if (!pchSupport && Utilities.versionCompare(version, "3.1.0") < 0){
+                        console.info("ccache is tool old, version >= 3.1.0 required to work with precompiled headers.");
+                        pchSupport = false;
+                    }
+
+                    if (pchSupport)
+                        console.info("ccache supports compilation with precompiled headers.")
+                }
+            } finally {
+                detector.close();
+            }
+        }
+    }
+}