qt4, qt5 modules: Improve moc/uic/rcc detection

Instead of blindly searching in PATH, use
Qt5Dependency.compilers_detect() (same for qt4) to get moc/uic/rcc.

This is much more robust, and it improves the chances that the correct
ones will be found. We still manually verify for now because the
fallback in dependencies.py for searching is stll to look in PATH for
backwards-compat, and because people probably have setups like that.

Also sync the qt4 module with the qt5 module w.r.t. resource compilation
and make the compiled qrc.cpp file unique in terms of the framework
version used (4 vs 5). This is needed for the test to work properly,
which now covers both Qt4 and 5.

3 files changed, 78 insertions, 68 deletions

diff --git a/mesonbuild/modules/qt4.py b/mesonbuild/modules/qt4.py
index 1c5a0d1..5108baa 100644
--- a/mesonbuild/modules/qt4.py
+++ b/mesonbuild/modules/qt4.py
@@ -12,26 +12,27 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .. import dependencies, mlog
 import os, subprocess
+from .. import mlog
 from .. import build
 from ..mesonlib import MesonException
+from ..dependencies import Qt4Dependency
 import xml.etree.ElementTree as ET
 
 class Qt4Module():
-    def __init__(self):
-        mlog.log('Detecting Qt tools.')
-        # The binaries have different names on different
-        # distros. Joy.
-        self.moc = dependencies.ExternalProgram('moc-qt4', silent=True)
-        if not self.moc.found():
-            self.moc = dependencies.ExternalProgram('moc', silent=True)
-        self.uic = dependencies.ExternalProgram('uic-qt4', silent=True)
-        if not self.uic.found():
-            self.uic = dependencies.ExternalProgram('uic', silent=True)
-        self.rcc = dependencies.ExternalProgram('rcc-qt4', silent=True)
-        if not self.rcc.found():
-            self.rcc = dependencies.ExternalProgram('rcc', silent=True)
+    tools_detected = False
+
+    def _detect_tools(self, env):
+        if self.tools_detected:
+            return
+        mlog.log('Detecting Qt4 tools')
+        # FIXME: We currently require Qt4 to exist while importing the module.
+        # We should make it gracefully degrade and not create any targets if
+        # the import is marked as 'optional' (not implemented yet)
+        kwargs = {'required': 'true', 'modules': 'Core', 'silent': 'true'}
+        qt4 = Qt4Dependency(env, kwargs)
+        # Get all tools and then make sure that they are the right version
+        self.moc, self.uic, self.rcc = qt4.compilers_detect()
         # Moc, uic and rcc write their version strings to stderr.
         # Moc and rcc return a non-zero result when doing so.
         # What kind of an idiot thought that was a good idea?
@@ -80,6 +81,7 @@ class Qt4Module():
                      % (' '.join(self.rcc.fullpath), rcc_ver.split()[-1]))
         else:
             mlog.log(' rcc:', mlog.red('NO'))
+        self.tools_detected = True
 
     def parse_qrc(self, state, fname):
         abspath = os.path.join(state.environment.source_dir, state.subdir, fname)
@@ -115,6 +117,7 @@ class Qt4Module():
         if not isinstance(srctmp, list):
             srctmp = [srctmp]
         sources = args[1:] + srctmp
+        self._detect_tools(state.environment)
         err_msg = "{0} sources specified and couldn't find {1}, " \
                   "please check your qt4 installation"
         if len(moc_headers) + len(moc_sources) > 0 and not self.moc.found():
@@ -122,16 +125,18 @@ class Qt4Module():
         if len(rcc_files) > 0:
             if not self.rcc.found():
                 raise MesonException(err_msg.format('RCC', 'rcc-qt4'))
-            rcc_kwargs = {'output' : '@BASENAME@.cpp',
-                          'arguments' : ['@INPUT@', '-o', '@OUTPUT@']}
-            rcc_gen = build.Generator([self.rcc], rcc_kwargs)
-            rcc_output = build.GeneratedList(rcc_gen)
             qrc_deps = []
             for i in rcc_files:
                 qrc_deps += self.parse_qrc(state, i)
-            rcc_output.extra_depends = qrc_deps
-            [rcc_output.add_file(os.path.join(state.subdir, a)) for a in rcc_files]
-            sources.append(rcc_output)
+            basename = os.path.split(rcc_files[0])[1]
+            name = 'qt4-' + basename.replace('.', '_')
+            rcc_kwargs = {'input' : rcc_files,
+                    'output' : name + '.cpp',
+                    'command' : [self.rcc, '-o', '@OUTPUT@', '@INPUT@'],
+                    'depend_files' : qrc_deps,
+                    }
+            res_target = build.CustomTarget(name, state.subdir, rcc_kwargs)
+            sources.append(res_target)
         if len(ui_files) > 0:
             if not self.uic.found():
                 raise MesonException(err_msg.format('UIC', 'uic-qt4'))
diff --git a/mesonbuild/modules/qt5.py b/mesonbuild/modules/qt5.py
index 01e9df1..52ad155 100644
--- a/mesonbuild/modules/qt5.py
+++ b/mesonbuild/modules/qt5.py
@@ -12,27 +12,27 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .. import dependencies, mlog
 import os, subprocess
+from .. import mlog
 from .. import build
 from ..mesonlib import MesonException
+from ..dependencies import Qt5Dependency
 import xml.etree.ElementTree as ET
 
 class Qt5Module():
+    tools_detected = False
 
-    def __init__(self):
-        mlog.log('Detecting Qt tools.')
-        # The binaries have different names on different
-        # distros. Joy.
-        self.moc = dependencies.ExternalProgram('moc-qt5', silent=True)
-        if not self.moc.found():
-            self.moc = dependencies.ExternalProgram('moc', silent=True)
-        self.uic = dependencies.ExternalProgram('uic-qt5', silent=True)
-        if not self.uic.found():
-            self.uic = dependencies.ExternalProgram('uic', silent=True)
-        self.rcc = dependencies.ExternalProgram('rcc-qt5', silent=True)
-        if not self.rcc.found():
-            self.rcc = dependencies.ExternalProgram('rcc', silent=True)
+    def _detect_tools(self, env):
+        if self.tools_detected:
+            return
+        mlog.log('Detecting Qt5 tools')
+        # FIXME: We currently require Qt5 to exist while importing the module.
+        # We should make it gracefully degrade and not create any targets if
+        # the import is marked as 'optional' (not implemented yet)
+        kwargs = {'required': 'true', 'modules': 'Core', 'silent': 'true'}
+        qt5 = Qt5Dependency(env, kwargs)
+        # Get all tools and then make sure that they are the right version
+        self.moc, self.uic, self.rcc = qt5.compilers_detect()
         # Moc, uic and rcc write their version strings to stderr.
         # Moc and rcc return a non-zero result when doing so.
         # What kind of an idiot thought that was a good idea?
@@ -87,6 +87,7 @@ class Qt5Module():
                      % (' '.join(self.rcc.fullpath), rcc_ver.split()[-1]))
         else:
             mlog.log(' rcc:', mlog.red('NO'))
+        self.tools_detected = True
 
     def parse_qrc(self, state, fname):
         abspath = os.path.join(state.environment.source_dir, state.subdir, fname)
@@ -122,6 +123,7 @@ class Qt5Module():
         if not isinstance(srctmp, list):
             srctmp = [srctmp]
         sources = args[1:] + srctmp
+        self._detect_tools(state.environment)
         err_msg = "{0} sources specified and couldn't find {1}, " \
                   "please check your qt5 installation"
         if len(moc_headers) + len(moc_sources) > 0 and not self.moc.found():
@@ -138,9 +140,8 @@ class Qt5Module():
                     'command' : [self.rcc, '-o', '@OUTPUT@', '@INPUT@'],
                     'depend_files' : qrc_deps,
                     }
-            res_target = build.CustomTarget(basename.replace('.', '_'),
-                                            state.subdir,
-                                            rcc_kwargs)
+            name = 'qt5-' + basename.replace('.', '_')
+            res_target = build.CustomTarget(name, state.subdir, rcc_kwargs)
             sources.append(res_target)
         if len(ui_files) > 0:
             if not self.uic.found():
diff --git a/test cases/frameworks/4 qt5/meson.build b/test cases/frameworks/4 qt5/meson.build
index 5672071..1096c78 100644
--- a/test cases/frameworks/4 qt5/meson.build
+++ b/test cases/frameworks/4 qt5/meson.build
@@ -1,41 +1,45 @@
-project('qt5 build test', 'cpp')
+project('qt4 and 5 build test', 'cpp')
 
-qt5 = import('qt5')
-qt5dep = dependency('qt5', modules : ['Core', 'Gui', 'Widgets'])
+foreach qt : ['qt4', 'qt5']
+  qtdep = dependency(qt, modules : ['Core', 'Gui', 'Widgets'], required : qt == 'qt5')
+  if qtdep.found()
+    qtmodule = import(qt)
 
-# The following has two resource files because having two in one target
-# requires you to do it properly or you get linker symbol clashes.
+    # The following has two resource files because having two in one target
+    # requires you to do it properly or you get linker symbol clashes.
 
-prep = qt5.preprocess(
-  moc_headers : ['mainWindow.h'],           # These need to be fed through the moc tool before use. 
-  ui_files : 'mainWindow.ui',               # XML files that need to be compiled with the uic tol.
-  qresources : ['stuff.qrc', 'stuff2.qrc'], # Resource file for rcc compiler.
-)
+    prep = qtmodule.preprocess(
+      moc_headers : ['mainWindow.h'],           # These need to be fed through the moc tool before use. 
+      ui_files : 'mainWindow.ui',               # XML files that need to be compiled with the uic tol.
+      qresources : ['stuff.qrc', 'stuff2.qrc'], # Resource file for rcc compiler.
+    )
 
-q5exe = executable('qt5app',
-  sources : ['main.cpp', 'mainWindow.cpp', # Sources that don't need preprocessing.
-  prep],
-  dependencies : qt5dep)
+    qexe = executable(qt + 'app',
+      sources : ['main.cpp', 'mainWindow.cpp', # Sources that don't need preprocessing.
+      prep],
+      dependencies : qtdep)
 
-# We need a console test application because some test environments
-# do not have an X server.
+    # We need a console test application because some test environments
+    # do not have an X server.
 
-qt5core = dependency('qt5', modules : 'Core')
+    qtcore = dependency(qt, modules : 'Core')
 
-qt5coreapp = executable('q5core', 'q5core.cpp',
-  dependencies : qt5core)
+    qtcoreapp = executable(qt + 'core', 'q5core.cpp',
+      dependencies : qtcore)
 
-test('qt5test', qt5coreapp)
+    test(qt + 'test', qtcoreapp)
 
-# The build system needs to include the cpp files from
-# headers but the user must manually include moc
-# files from sources.
-manpreprocessed = qt5.preprocess(
-  moc_sources : 'manualinclude.cpp',
-  moc_headers : 'manualinclude.h')
+    # The build system needs to include the cpp files from
+    # headers but the user must manually include moc
+    # files from sources.
+    manpreprocessed = qtmodule.preprocess(
+      moc_sources : 'manualinclude.cpp',
+      moc_headers : 'manualinclude.h')
 
-q5maninclude = executable('q5maninclude',
-  sources : ['manualinclude.cpp', manpreprocessed],
-  dependencies : qt5core)
+    qtmaninclude = executable(qt + 'maninclude',
+      sources : ['manualinclude.cpp', manpreprocessed],
+      dependencies : qtcore)
 
-test('q5maninclude', q5maninclude)
+    test(qt + 'maninclude', qtmaninclude)
+  endif
+endforeach