Consolidate reporting result of a dependency check

If successful, we should identify the method which was successful
If successful, we should report the version found (if known)
If failing, we should identify the methods we tried

Some dependency detectors which had no reporting now gain it

There's all kinds of complexities, inconsistencies and special cases hidden
in the existing behaviour, e.g.:

- boost reports modules requested, and BOOST_ROOT (if set)
- gtest/gmock report if they are a prebuilt library or header only
- mpi reports the language
- qt reports modules requested, and the config tool used or tried
- configtool reports the config tool used
- llvm reports if missing modules are optional (one per line)

We add some simple hooks to allow the dependency object to expose the
currently reported information into the consolidated reporting

Note that PkgConfigDependency() takes a silent: keyword which is used
internallly to suppress reporting.  This behaviour isn't needed in
find_external_dependency().

1 files changed, 30 insertions, 9 deletions

diff --git a/mesonbuild/dependencies/dev.py b/mesonbuild/dependencies/dev.py
index 4ea3385..0cd3c2b 100644
--- a/mesonbuild/dependencies/dev.py
+++ b/mesonbuild/dependencies/dev.py
@@ -45,7 +45,7 @@ class GTestDependency(ExternalDependency):
             if self.main:
                 self.link_args += gtest_main_detect
             self.sources = []
-            mlog.log('Dependency GTest found:', mlog.green('YES'), '(prebuilt)')
+            self.prebuilt = True
         elif self.detect_srcdir():
             self.is_found = True
             self.compile_args = ['-I' + d for d in self.src_include_dirs]
@@ -54,9 +54,8 @@ class GTestDependency(ExternalDependency):
                 self.sources = [self.all_src, self.main_src]
             else:
                 self.sources = [self.all_src]
-            mlog.log('Dependency GTest found:', mlog.green('YES'), '(building self)')
+            self.prebuilt = False
         else:
-            mlog.log('Dependency GTest found:', mlog.red('NO'))
             self.is_found = False
 
     def detect_srcdir(self):
@@ -76,6 +75,12 @@ class GTestDependency(ExternalDependency):
     def need_threads(self):
         return True
 
+    def log_info(self):
+        if self.prebuilt:
+            return 'prebuilt'
+        else:
+            return 'building self'
+
 
 class GMockDependency(ExternalDependency):
     def __init__(self, environment, kwargs):
@@ -89,7 +94,7 @@ class GMockDependency(ExternalDependency):
             self.compile_args = []
             self.link_args = gmock_detect
             self.sources = []
-            mlog.log('Dependency GMock found:', mlog.green('YES'), '(prebuilt)')
+            self.prebuilt = True
             return
 
         for d in ['/usr/src/googletest/googlemock/src', '/usr/src/gmock/src', '/usr/src/gmock']:
@@ -106,11 +111,17 @@ class GMockDependency(ExternalDependency):
                     self.sources = [all_src, main_src]
                 else:
                     self.sources = [all_src]
-                mlog.log('Dependency GMock found:', mlog.green('YES'), '(building self)')
+                self.prebuilt = False
                 return
-        mlog.log('Dependency GMock found:', mlog.red('NO'))
+
         self.is_found = False
 
+    def log_info(self):
+        if self.prebuilt:
+            return 'prebuilt'
+        else:
+            return 'building self'
+
 
 class LLVMDependency(ConfigToolDependency):
     """
@@ -145,6 +156,7 @@ class LLVMDependency(ConfigToolDependency):
         super().__init__('LLVM', environment, 'cpp', kwargs)
         self.provided_modules = []
         self.required_modules = set()
+        self.module_details = []
         if not self.is_found:
             return
         self.static = kwargs.get('static', False)
@@ -237,21 +249,30 @@ class LLVMDependency(ConfigToolDependency):
         is required.
         """
         for mod in sorted(set(modules)):
+            status = ''
+
             if mod not in self.provided_modules:
-                mlog.log('LLVM module', mlog.bold(mod), 'found:', mlog.red('NO'),
-                         '(optional)' if not required else '')
                 if required:
                     self.is_found = False
                     if self.required:
                         raise DependencyException(
                             'Could not find required LLVM Component: {}'.format(mod))
+                    status = '(missing)'
+                else:
+                    status = '(missing but optional)'
             else:
                 self.required_modules.add(mod)
-                mlog.log('LLVM module', mlog.bold(mod), 'found:', mlog.green('YES'))
+
+            self.module_details.append(mod + status)
 
     def need_threads(self):
         return True
 
+    def log_details(self):
+        if self.module_details:
+            return 'modules: ' + ', '.join(self.module_details)
+        return ''
+
 
 class ValgrindDependency(PkgConfigDependency):
     '''