qbs build: Introduce libclang module.

This is The Right Way to detect libclang. Using a Probe will also
slightly improve performance in qbs 1.6 due to the result caching.

Change-Id: I063a8d108d02b620dda2df75dd8c014c84f27ec7
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

qbs/imports/QtcProcessOutputReader/procoutputreader.js

-var Process = loadExtension("qbs.Process")
-
-function readOutput(executable, args)
-{
-    var p = new Process();
-    var output = "";
-    if (p.exec(executable, args, false) !== -1)
-        output = p.readStdOut().trim(); // Trailing newline.
-    p.close();
-    return output;
-}

qbs/imports/QtcClangInstallation/functions.js → qbs/modules/libclang/functions.js

 var Environment = loadExtension("qbs.Environment")
 var File = loadExtension("qbs.File")
 var MinimumLLVMVersion = "3.6.2"
+var Process = loadExtension("qbs.Process")
 
-function isSuitableLLVMConfig(llvmConfigCandidate, qtcFunctions, processOutputReader)
+function readOutput(executable, args)
+{
+    var p = new Process();
+    var output = "";
+    if (p.exec(executable, args, false) !== -1)
+        output = p.readStdOut().trim(); // Trailing newline.
+    p.close();
+    return output;
+}
+
+function isSuitableLLVMConfig(llvmConfigCandidate, qtcFunctions)
 {
     if (File.exists(llvmConfigCandidate)) {
-        var candidateVersion = version(llvmConfigCandidate, processOutputReader);
+        var candidateVersion = version(llvmConfigCandidate);
         if (candidateVersion && candidateVersion.length)
             return qtcFunctions.versionIsAtLeast(candidateVersion, MinimumLLVMVersion)
     }
     return false;
 }
 
-function llvmConfig(qbs, qtcFunctions, processOutputReader)
+function llvmConfig(qbs, qtcFunctions)
 {
     var llvmInstallDirFromEnv = Environment.getEnv("LLVM_INSTALL_DIR")
     var llvmConfigVariants = [
@@ -25,7 +36,7 @@ function llvmConfig(qbs, qtcFunctions, processOutputReader)
     if (llvmInstallDirFromEnv) {
         for (var i = 0; i < llvmConfigVariants.length; ++i) {
             var variant = llvmInstallDirFromEnv + "/bin/" + llvmConfigVariants[i] + suffix;
-            if (isSuitableLLVMConfig(variant, qtcFunctions, processOutputReader))
+            if (isSuitableLLVMConfig(variant, qtcFunctions))
                 return variant;
         }
     }
@@ -37,7 +48,7 @@ function llvmConfig(qbs, qtcFunctions, processOutputReader)
     for (var i = 0; i < llvmConfigVariants.length; ++i) {
         for (var j = 0; j < pathList.length; ++j) {
             var variant = pathList[j] + "/" + llvmConfigVariants[i] + suffix;
-            if (isSuitableLLVMConfig(variant, qtcFunctions, processOutputReader))
+            if (isSuitableLLVMConfig(variant, qtcFunctions))
                 return variant;
         }
     }
@@ -45,20 +56,19 @@ function llvmConfig(qbs, qtcFunctions, processOutputReader)
     return undefined;
 }
 
-function includeDir(llvmConfig, processOutputReader)
+function includeDir(llvmConfig)
 {
-    return processOutputReader.readOutput(llvmConfig, ["--includedir"])
+    return readOutput(llvmConfig, ["--includedir"])
 }
 
-function libDir(llvmConfig, processOutputReader)
+function libDir(llvmConfig)
 {
-    return processOutputReader.readOutput(llvmConfig, ["--libdir"])
+    return readOutput(llvmConfig, ["--libdir"])
 }
 
-function version(llvmConfig, processOutputReader)
+function version(llvmConfig)
 {
-    return processOutputReader.readOutput(llvmConfig, ["--version"])
-        .replace(/(\d+\.\d+\.\d+).*/, "$1")
+    return readOutput(llvmConfig, ["--version"]).replace(/(\d+\.\d+\.\d+).*/, "$1")
 }
 
 function libraries(targetOS)

qbs/modules/libclang/libclang.qbs

+import qbs
+import qbs.File
+import QtcFunctions
+import "functions.js" as ClangFunctions
+
+Module {
+    Probe {
+        id: clangProbe
+
+        property string llvmConfig
+        property string llvmIncludeDir
+        property string llvmLibDir
+        property stringList llvmLibs
+
+        configure: {
+            llvmConfig = ClangFunctions.llvmConfig(qbs, QtcFunctions);
+            llvmIncludeDir = ClangFunctions.includeDir(llvmConfig);
+            llvmLibDir = ClangFunctions.libDir(llvmConfig);
+            llvmLibs = ClangFunctions.libraries(qbs.targetOS);
+            found = llvmConfig && File.exists(llvmIncludeDir.concat("/clang-c/Index.h"));
+        }
+    }
+
+    property string llvmConfig: clangProbe.llvmConfig
+    property string llvmIncludeDir: clangProbe.llvmIncludeDir
+    property string llvmLibDir: clangProbe.llvmLibDir
+    property stringList llvmLibs: clangProbe.llvmLibs
+
+    validate: {
+        if (!clangProbe.found)
+            throw "No usable libclang found";
+    }
+}

src/plugins/clangcodemodel/clangcodemodel.qbs

 import qbs
-import qbs.File
-import QtcClangInstallation as Clang
-import QtcFunctions
-import QtcProcessOutputReader
+import qbs.FileInfo
 
 QtcPlugin {
     name: "ClangCodeModel"
@@ -14,24 +11,22 @@ QtcPlugin {
     Depends { name: "TextEditor" }
     Depends { name: "Utils" }
     Depends { name: "ClangBackEndIpc" }
+    Depends { name: "libclang"; required: false }
 
     pluginTestDepends: [
         "CppEditor",
         "QmakeProjectManager",
     ]
 
-    property string llvmConfig: Clang.llvmConfig(qbs, QtcFunctions, QtcProcessOutputReader)
-    property string llvmIncludeDir: Clang.includeDir(llvmConfig, QtcProcessOutputReader)
-    property string llvmLibDir: Clang.libDir(llvmConfig, QtcProcessOutputReader)
-    property string llvmVersion: Clang.version(llvmConfig, QtcProcessOutputReader)
-
-    condition: llvmConfig && File.exists(llvmIncludeDir.concat("/clang-c/Index.h"))
+    condition: libclang.present
 
     cpp.defines: {
         var defines = base;
         // The following defines are used to determine the clang include path for intrinsics.
-        defines.push('CLANG_VERSION="' + llvmVersion + '"');
-        defines.push('CLANG_RESOURCE_DIR="' + llvmLibDir + '/clang/' + llvmVersion + '/include"');
+        defines.push('CLANG_VERSION="' + libclang.llvmVersion + '"');
+        var resourceDir = FileInfo.joinPaths(libclang.llvmLibDir, "clang", libclang.llvmVersion,
+                                             "include");
+        defines.push('CLANG_RESOURCE_DIR="' + resourceDir + '"');
         return defines;
     }
 

src/tools/clangbackend/clangbackend.qbs

 import qbs 1.0
-import qbs.File
-import QtcClangInstallation as Clang
-import QtcFunctions
-import QtcProcessOutputReader
 
 QtcTool {
     name: "clangbackend"
 
     Depends { name: "ClangBackEndIpc" }
+    Depends { name: "libclang"; required: false }
 
     Group {
         prefix: "ipcsource/"
@@ -19,17 +16,12 @@ QtcTool {
 
     files: [ "clangbackendmain.cpp" ]
 
-    property string llvmConfig: Clang.llvmConfig(qbs, QtcFunctions, QtcProcessOutputReader)
-    property string llvmIncludeDir: Clang.includeDir(llvmConfig, QtcProcessOutputReader)
-    property string llvmLibDir: Clang.libDir(llvmConfig, QtcProcessOutputReader)
-    property stringList llvmLibs: Clang.libraries(qbs.targetOS)
+    condition: libclang.present
 
-    condition: llvmConfig && File.exists(llvmIncludeDir.concat("/clang-c/Index.h"))
-
-    cpp.includePaths: base.concat(["ipcsource", llvmIncludeDir])
-    cpp.libraryPaths: base.concat(llvmLibDir)
-    cpp.dynamicLibraries: base.concat(llvmLibs)
-    cpp.rpaths: base.concat(llvmLibDir)
+    cpp.includePaths: base.concat(["ipcsource", libclang.llvmIncludeDir])
+    cpp.libraryPaths: base.concat(libclang.llvmLibDir)
+    cpp.dynamicLibraries: base.concat(libclang.llvmLibs)
+    cpp.rpaths: base.concat(libclang.llvmLibDir)
 
     Properties {
         condition: qbs.targetOS.contains("unix") && !qbs.targetOS.contains("osx")