Setup project database infrastructure

1 files changed, 88 insertions, 0 deletions

diff --git a/bdep/database.cxx b/bdep/database.cxx
new file mode 100644
index 0000000..c456961
--- /dev/null
+++ b/bdep/database.cxx
@@ -0,0 +1,88 @@
+// file      : bdep/database.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <bdep/database.hxx>
+
+#include <odb/schema-catalog.hxx>
+#include <odb/sqlite/exceptions.hxx>
+
+#include <bdep/diagnostics.hxx>
+
+using namespace std;
+
+namespace bdep
+{
+  using namespace odb::sqlite;
+  using odb::schema_catalog;
+
+  database
+  open (const dir_path& d, tracer& tr, bool create)
+  {
+    tracer trace ("open");
+
+    path f (d / bdep_dir / "bdep.sqlite3");
+
+    if (!create && !exists (f))
+      fail << d << " does not look like an initialized project directory" <<
+        info << "run 'bdep init' to initialize";
+
+    try
+    {
+      // We don't need the thread pool.
+      //
+      unique_ptr<connection_factory> cf (new single_connection_factory);
+
+      database db (f.string (),
+                   SQLITE_OPEN_READWRITE | (create ? SQLITE_OPEN_CREATE : 0),
+                   true,                  // Enable FKs.
+                   "",                    // Default VFS.
+                   move (cf));
+
+      db.tracer (trace);
+
+      // Lock the database for as long as the connection is active. First we
+      // set locking_mode to EXCLUSIVE which instructs SQLite not to release
+      // any locks until the connection is closed. Then we force SQLite to
+      // acquire the write lock by starting exclusive transaction. See the
+      // locking_mode pragma documentation for details. This will also fail if
+      // the database is inaccessible (e.g., file does not exist, already used
+      // by another process, etc).
+      //
+      try
+      {
+        db.connection ()->execute ("PRAGMA locking_mode = EXCLUSIVE");
+        transaction t (db.begin_exclusive ());
+
+        if (create)
+        {
+          // Create the new schema.
+          //
+          if (db.schema_version () != 0)
+            fail << f << ": already has database schema";
+
+          schema_catalog::create_schema (db);
+        }
+        else
+        {
+          // Migrate the database if necessary.
+          //
+          schema_catalog::migrate (db);
+        }
+
+        t.commit ();
+      }
+      catch (odb::timeout&)
+      {
+        fail << "project " << d << " is already used by another process";
+      }
+
+      db.tracer (tr); // Switch to the caller's tracer.
+      return db;
+    }
+    catch (const database_exception& e)
+    {
+      fail << f << ": " << e.message () << endf;
+    }
+  }
+}