Add Config::compilationDatabaseCommand

If specified, this is an external command that provides the JSON compilation database, instead of compile_commands.json

src/config.h

@@ -23,6 +23,11 @@ initialization options specified by the client. For example, in shell syntax:
 struct Config {
   // Root directory of the project. **Not available for configuration**
   std::string projectRoot;
+  // If specified, this option overrides compile_commands.json and this
+  // external command will be executed with an option |projectRoot|.
+  // The initialization options will be provided as stdin.
+  // The stdout of the command should be the JSON compilation database.
+  std::string compilationDatabaseCommand;
   // Directory containing compile_commands.json.
   std::string compilationDatabaseDirectory;
   // Cache directory for indexed files.
@@ -191,6 +196,7 @@ MAKE_REFLECT_STRUCT(Config::Completion, filterAndSort, detailedLabel);
 MAKE_REFLECT_STRUCT(Config::Extension, referenceContainer);
 MAKE_REFLECT_STRUCT(Config::Index, comments, attributeMakeCallsToCtor);
 MAKE_REFLECT_STRUCT(Config,
+                    compilationDatabaseCommand,
                     compilationDatabaseDirectory,
                     cacheDirectory,
                     cacheFormat,

src/indexer.cc

@@ -330,8 +330,8 @@ IndexFile* ConsumeFile(IndexParam* param, CXFile file) {
   // generating an index for it):
   if (param->seen_cx_files.insert(file).second) {
     std::string file_name = FileName(file);
-    // Sometimes the fill name will be empty. Not sure why. Not much we can do
-    // with it.
+    // file_name may be empty when it contains .. and is outside of WorkingDir.
+    // https://reviews.llvm.org/D42893 https://github.com/cquery-project/cquery/issues/413
     if (!file_name.empty()) {
       // Add to all files we have seen so we can generate proper dependency
       // graph.

src/platform.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <optional.h>
+#include <string_view.h>
 
 #include <memory>
 #include <string>
@@ -49,4 +50,8 @@ void FreeUnusedMemory();
 // If true objective-c index tests will be run.
 bool RunObjectiveCIndexTests();
 
+// Stop self and wait for SIGCONT.
 void TraceMe();
+
+std::string GetExternalCommandOutput(const std::vector<std::string>& command,
+                                     std::string_view input);

src/platform_posix.cc

@@ -27,6 +27,7 @@
 #include <dirent.h>
 #include <sys/stat.h>
 #include <sys/types.h>  // required for stat.h
+#include <sys/wait.h>
 
 #include <errno.h>
 #include <fcntl.h>
@@ -285,4 +286,37 @@ void TraceMe() {
     raise(SIGTSTP);
 }
 
+std::string GetExternalCommandOutput(const std::vector<std::string>& command,
+                                     std::string_view input) {
+  int pin[2], pout[2];
+  pipe(pin);
+  pipe(pout);
+  pid_t child = fork();
+  if (child == 0) {
+    dup2(pout[0], 0);
+    dup2(pin[1], 1);
+    close(pin[0]);
+    close(pin[1]);
+    close(pout[0]);
+    close(pout[1]);
+    auto argv = new char*[command.size() + 1];
+    for (size_t i = 0; i < command.size(); i++)
+      argv[i] = const_cast<char*>(command[i].c_str());
+    argv[command.size()] = nullptr;
+    execvp(argv[0], argv);
+    _Exit(127);
+  }
+  close(pin[1]);
+  close(pout[0]);
+  write(pout[1], input.data(), input.size());
+  close(pout[1]);
+  std::string ret;
+  char buf[4096];
+  ssize_t n;
+  while ((n = read(pin[0], buf, sizeof buf)) > 0)
+    ret.append(buf, n);
+  waitpid(child, NULL, 0);
+  return ret;
+}
+
 #endif

src/platform_win.cc

@@ -152,4 +152,9 @@ bool RunObjectiveCIndexTests() {
 // TODO Wait for debugger to attach
 void TraceMe() {}
 
+std::string GetExternalCommandOutput(const std::vector<std::string>& command,
+                                     std::string_view input) {
+  return "";
+}
+
 #endif

src/project.cc

@@ -11,6 +11,11 @@
 #include <doctest/doctest.h>
 #include <loguru.hpp>
 
+#if defined(__unix__) || defined(__APPLE__)
+#include <unistd.h>
+#endif
+
+#include <fstream>
 #include <iostream>
 #include <limits>
 #include <sstream>
@@ -348,17 +353,48 @@ std::vector<Project::Entry> LoadCompilationEntriesFromDirectory(
   if (FileExists(config->project_dir + "/.cquery"))
     return LoadFromDirectoryListing(init_opts, config);
 
-  // Try to load compile_commands.json, but fallback to a project listing.
-  const auto& compilation_db_dir = opt_compilation_db_dir.empty()
-                                       ? config->project_dir
-                                       : opt_compilation_db_dir;
+  // If |compilationDatabaseCommand| is specified, execute it to get the compdb.
+  std::string comp_db_dir;
+  if (init_opts->compilationDatabaseCommand.empty()) {
+    // Try to load compile_commands.json, but fallback to a project listing.
+    comp_db_dir = opt_compilation_db_dir.empty() ? config->project_dir
+                                                 : opt_compilation_db_dir;
+  } else {
+#ifdef _WIN32
+    // TODO
+#else
+    char tmpdir[] = "/tmp/cquery-compdb-XXXXXX";
+    if (!mkdtemp(tmpdir))
+      return {};
+    comp_db_dir = tmpdir;
+    rapidjson::StringBuffer input;
+    rapidjson::Writer<rapidjson::StringBuffer> writer(input);
+    JsonWriter json_writer(&writer);
+    Reflect(json_writer, *init_opts);
+    std::string contents = GetExternalCommandOutput(
+        std::vector<std::string>{init_opts->compilationDatabaseCommand,
+                                 config->project_dir},
+        input.GetString());
+    std::ofstream(comp_db_dir + "/compile_commands.json") << contents;
+#endif
+  }
+
   LOG_S(INFO) << "Trying to load compile_commands.json";
   CXCompilationDatabase_Error cx_db_load_error;
   CXCompilationDatabase cx_db = clang_CompilationDatabase_fromDirectory(
-      compilation_db_dir.c_str(), &cx_db_load_error);
+      comp_db_dir.c_str(), &cx_db_load_error);
+  if (!init_opts->compilationDatabaseCommand.empty()) {
+#ifdef _WIN32
+    // TODO
+#else
+    unlink((comp_db_dir + "/compile_commands.json").c_str());
+    rmdir(comp_db_dir.c_str());
+#endif
+  }
+
   if (cx_db_load_error == CXCompilationDatabase_CanNotLoadDatabase) {
     LOG_S(INFO) << "Unable to load compile_commands.json located at \""
-                << compilation_db_dir << "\"; using directory listing instead.";
+                << comp_db_dir << "\"; using directory listing instead.";
     return LoadFromDirectoryListing(init_opts, config);
   }
 
@@ -416,7 +452,6 @@ std::vector<Project::Entry> LoadCompilationEntriesFromDirectory(
 
   clang_time.ResetAndPrint("compile_commands.json clang time");
   our_time.ResetAndPrint("compile_commands.json our time");
-
   return result;
 }