Add compilation database generation.

5 files changed, 106 insertions, 42 deletions

diff --git a/TODO b/TODO
index 34fe79a..2715747 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,6 @@
 Glob convenience methods
 std::string glob = getFilesInDir(...);
 
-Generate compilation database
-https://clang.llvm.org/docs/JSONCompilationDatabase.html
-
 Add support for pre/post build hooks with conditions
 
 Add shell script targets to be able to generate soucre files that can
diff --git a/libcppbuild.cc b/libcppbuild.cc
index 9fcc4d4..8d5231f 100644
--- a/libcppbuild.cc
+++ b/libcppbuild.cc
@@ -11,6 +11,7 @@
 #include <list>
 #include <array>
 #include <deque>
+#include <fstream>
 
 #include <getoptpp/getoptpp.hpp>
 
@@ -179,6 +180,9 @@ int main(int argc, char* argv[])
 		std::max(1u, std::thread::hardware_concurrency() * 2 - 1);
 	settings.verbose = 0;
 
+	bool write_compilation_database{false};
+	std::string compilation_database;
+
 	dg::Options opt;
 
 	opt.add("jobs", required_argument, 'j',
@@ -210,6 +214,14 @@ int main(int argc, char* argv[])
 		        return 0;
 	        });
 
+	opt.add("database", required_argument, 'd',
+	        "Write compilation database json file.",
+	        [&]() {
+		        write_compilation_database = true;
+		        compilation_database = optarg;
+		        return 0;
+	        });
+
 	opt.add("help", no_argument, 'h',
 	        "Print this help text.",
 	        [&]() {
@@ -246,6 +258,31 @@ int main(int argc, char* argv[])
 		}
 	}
 
+	if(write_compilation_database)
+	{
+		std::ofstream istr(compilation_database);
+		istr << "[";
+		bool first{true};
+		for(auto task : tasks)
+		{
+			auto s = task->toJSON();
+			if(!s.empty())
+			{
+				if(!first)
+				{
+					istr << ",\n";
+				}
+				else
+				{
+					istr << "\n";
+				}
+				first = false;
+				istr << s;
+			}
+		}
+		istr << "\n]\n";
+	}
+
 	for(auto task : tasks)
 	{
 		if(task->registerDepTasks(tasks))
diff --git a/task.h b/task.h
index f7a4758..9c2d622 100644
--- a/task.h
+++ b/task.h
@@ -31,6 +31,8 @@ public:
 	virtual std::vector<std::string> depends() const = 0;
 	virtual std::string target() const = 0;
 
+	virtual std::string toJSON() const { return {}; };
+
 protected:
 	std::atomic<State> task_state{State::Unknown};
 	virtual int runInner() { return 0; };
diff --git a/task_cc.cc b/task_cc.cc
index b5cc768..6c7e3b7 100644
--- a/task_cc.cc
+++ b/task_cc.cc
@@ -175,44 +175,7 @@ int TaskCC::runInner()
 		return 1;
 	}
 
-	std::string comp = compiler();
-	auto compiler_flags = flags();
-
-	std::vector<std::string> args;
-	args.push_back("-MMD");
-
-	if(std::filesystem::path(config.target).extension() == ".so")
-	{
-		// Add -fPIC arg to all contained object files
-		args.push_back("-fPIC");
-	}
-
-	args.push_back("-c");
-	args.push_back(std::string(sourceFile));
-	args.push_back("-o");
-	args.push_back(std::string(targetFile));
-
-	for(const auto& flag : compiler_flags)
-	{
-		// Is arg an added include path?
-		if(flag.substr(0, 2) == "-I")
-		{
-			std::string include_path = flag.substr(2);
-			include_path.erase(0, include_path.find_first_not_of(' '));
-			std::filesystem::path path(include_path);
-
-			// Is it relative?
-			if(path.is_relative())
-			{
-				path = (sourceDir / path).lexically_normal();
-				std::string new_include_path = "-I" + path.string();
-				args.push_back(new_include_path);
-				continue;
-			}
-		}
-
-		args.push_back(flag);
-	}
+	auto args = getCompilerArgs();
 
 	{ // Write flags to file.
 		std::ofstream flagsStream(flagsFile);
@@ -225,7 +188,8 @@ int TaskCC::runInner()
 			sourceFile.lexically_normal().string() << " => " <<
 			targetFile.lexically_normal().string() << "\n";
 	}
-	return execute(comp, args, settings.verbose > 0);
+
+	return execute(compiler(), args, settings.verbose > 0);
 }
 
 int TaskCC::clean()
@@ -261,6 +225,24 @@ std::string TaskCC::target() const
 	return targetFile;
 }
 
+std::string TaskCC::toJSON() const
+{
+	std::string json;
+	json += "\t{\n";
+	json += "\t\t\"directory\": \"" + sourceDir.string() + "\",\n";
+	json += "\t\t\"file\": \"" + sourceFile.lexically_normal().string() + "\",\n";
+	json += "\t\t\"output\": \"" + targetFile.string() + "\",\n";
+	json += "\t\t\"arguments\": [ \"" + compiler() + "\"";
+	auto args = getCompilerArgs();
+	for(const auto& arg : args)
+	{
+		json += ", \"" + arg + "\"";
+	}
+	json += " ]\n";
+	json += "\t}";
+	return json;
+}
+
 std::vector<std::string> TaskCC::flags() const
 {
 	if(std::string(sourceFile.extension()) == ".c")
@@ -292,3 +274,46 @@ std::string TaskCC::compiler() const
 	}
 	return "/usr/bin/g++";
 }
+
+std::vector<std::string> TaskCC::getCompilerArgs() const
+{
+	auto compiler_flags = flags();
+
+	std::vector<std::string> args;
+	args.push_back("-MMD");
+
+	if(std::filesystem::path(config.target).extension() == ".so")
+	{
+		// Add -fPIC arg to all contained object files
+		args.push_back("-fPIC");
+	}
+
+	args.push_back("-c");
+	args.push_back(std::string(sourceFile));
+	args.push_back("-o");
+	args.push_back(std::string(targetFile));
+
+	for(const auto& flag : compiler_flags)
+	{
+		// Is arg an added include path?
+		if(flag.substr(0, 2) == "-I")
+		{
+			std::string include_path = flag.substr(2);
+			include_path.erase(0, include_path.find_first_not_of(' '));
+			std::filesystem::path path(include_path);
+
+			// Is it relative?
+			if(path.is_relative())
+			{
+				path = (sourceDir / path).lexically_normal();
+				std::string new_include_path = "-I" + path.string();
+				args.push_back(new_include_path);
+				continue;
+			}
+		}
+
+		args.push_back(flag);
+	}
+
+	return args;
+}
diff --git a/task_cc.h b/task_cc.h
index 538188f..48910c3 100644
--- a/task_cc.h
+++ b/task_cc.h
@@ -28,10 +28,13 @@ public:
 
 	std::string target() const override;
 
+	std::string toJSON() const override;
+
 private:
 	std::vector<std::string> flags() const;
 	std::string flagsString() const;
 	std::string compiler() const;
+	std::vector<std::string> getCompilerArgs() const;
 
 	std::filesystem::path sourceFile;
 	std::filesystem::path targetFile;