Added support for "no-parallel-build" option

This commit adds support for forcing a buildfile to be built in
non-parallel by introducing a new options list and a special toggle
option named "no-parallel-build".

To force a buildfile to be built in non-parallel, simply add to
buildfile:

options=no-parallel-build

This is reported to be useful for eg. kernel module builds which must
avoid to be built at the same time because they operate in the same
kernel build workspace.

In the future, more options might be supported in the options list.

man/buildgear-buildfile.man5

@@ -48,6 +48,13 @@ List of sources needed in the build procedure. Sources can be remote (protocols
 List of Buildgear builds that is needed by the build. These builds will be added to the sysroot before building of the selected build is started. Both compile-time and run-time dependencies can be specified. If the build dependency is in the native branch, the name of the build must be given as \fInative/<build name>\fR.
 .RE
 
+.TP
+.B options
+.RS
+List of special options. Currently only the \fBno-parallel-build\fR option is supported which forces a particular build to be built in non-parallel.
+.RE
+
+
 .SH FUNCTIONS
 
 .TP

src/buildfile.cc

@@ -48,6 +48,7 @@ CBuildFile::CBuildFile(string filename)
    CBuildFile::description = "";
    CBuildFile::url = "";
    CBuildFile::license = "";
+   CBuildFile::options.no_parallel_build = false;
 }
 
 string CBuildFile::GetLocation()
@@ -116,6 +117,7 @@ void CBuildFile::Parse(void)
        ; echo release=$release \
        ; echo source=${source[@]} \
        ; echo depends=${depends[@]} \
+       ; echo options=${options[@]} \
        ; typeset -F build &> /dev/null && echo build_function=yes || echo build_function=no \
        ; typeset -F check &> /dev/null && echo check_function=yes || echo check_function=no'";
 
@@ -206,10 +208,16 @@ void CBuildFile::Parse(void)
          source = value;
       if (key == KEY_DEPENDS)
          depends = value;
-      if (key == "build_function")
+      if (key == KEY_BUILD_FUNCTION)
          build_function = value;
-      if (key == "check_function")
+      if (key == KEY_CHECK_FUNCTION)
          check_function = value;
+      if (key == KEY_OPTIONS_)
+      {
+          // Parse options field
+          if (value.find("no-parallel-build") < value.length())
+              options.no_parallel_build = true;
+      }
    }
    pclose(fp);
 

src/buildmanager.cc

@@ -501,7 +501,7 @@ void CBuildManager::Build(list<CBuildFile*> *buildfiles)
       if (sem_init(&build_semaphore, 0,
                    stoi(Config.bg_config[CONFIG_KEY_PARALLEL_BUILDS])) == -1)
       {
-         cerr << "Error: Semaphore init failed" << endl;
+         cerr << "Error: Build semaphore init failed" << endl;
          exit(EXIT_FAILURE);
       }
 
@@ -514,14 +514,27 @@ void CBuildManager::Build(list<CBuildFile*> *buildfiles)
       while (it != buildfiles->end())
       {
          int thread_count=0;
+         list<CBuildFile*> no_parallel_buildfiles;
+         list<CBuildFile*>::iterator itr;
+
+         // Start building threads of same depth in parallel
          while ( ((*it)->depth == current_depth) && (it != buildfiles->end())
                  && !BuildManager.build_error)
          {
-            // Start building threads of same depth in parallel
-            CBuildThread *bt = new CBuildThread(*it);
-            builder.push_back(bt);
-            builder[thread_count]->Start();
-            thread_count++;
+            // Only build buildfiles in parallel which are not marked with the
+            // "no-parallel-build" option
+            if ((*it)->options.no_parallel_build == false)
+            {
+               CBuildThread *bt = new CBuildThread(*it);
+               builder.push_back(bt);
+               builder[thread_count]->Start();
+               thread_count++;
+            }
+            else
+            {
+                // Add for later sequential build deployment
+                no_parallel_buildfiles.push_back(*it);
+            }
             it++;
          }
 
@@ -535,6 +548,18 @@ void CBuildManager::Build(list<CBuildFile*> *buildfiles)
             builder.pop_back();
          }
 
+         // Build "no-parallel-build" marked builds sequentially
+         for (itr = no_parallel_buildfiles.begin(); itr != no_parallel_buildfiles.end(); itr++)
+         {
+            CBuildThread *bt = new CBuildThread(*itr);
+            (bt)->Start();
+            (bt)->Join();
+            if (BuildManager.build_error)
+               break;
+         }
+
+         no_parallel_buildfiles.clear();
+
          if (BuildManager.build_error)
             break;
 

src/include/buildgear/buildfile.h

@@ -44,6 +44,12 @@ class CBuildFile : public CUtility
       string release;
       string source;
       string depends;
+
+      struct
+         {
+            bool no_parallel_build;
+         } options;
+
       string missing_depends;
       string type;
       string build_function;

src/include/buildgear/config.h

@@ -130,6 +130,9 @@ class CConfig : public CUtility
 #define KEY_RELEASE              "release"
 #define KEY_SOURCE               "source"
 #define KEY_DEPENDS              "depends"
+#define KEY_OPTIONS_             "options"
+#define KEY_BUILD_FUNCTION       "build_function"
+#define KEY_CHECK_FUNCTION       "check_function"
 #define KEY_CONFIG_RETURN        "config_return"
 #define KEY_BUILD_RETURN         "build_return"