When loading sessions, create any missing session directories rather than throwing an exception.

Change the meaning of the return value of SessionDirectory::create and add documentation to explain usage.

Add PBD::sys::filesystem_error to indicate a filesystem error and throw it where necessary.

Change the semantics of PBD::sys::create_directory/ies functions to match boost::filesystem


git-svn-id: svn://localhost/ardour2/trunk@1884 d708f5d6-7413-0410-9779-e7cbd77b26cf

5 files changed, 109 insertions, 28 deletions

diff --git a/libs/ardour/ardour/session_directory.h b/libs/ardour/ardour/session_directory.h
index 131812c130..d23c135e0b 100644
--- a/libs/ardour/ardour/session_directory.h
+++ b/libs/ardour/ardour/session_directory.h
@@ -80,8 +80,15 @@ public:
 	bool is_valid () const;
 
 	/**
-	 * @return true If a new session directory and all the 
-	 * subdirectories were created, otherwise false.
+	 * Create the session directory and all the subdirectories.
+	 *
+	 * @throw PBD::sys::filesystem_error if the directories were
+	 * not able to be created.
+	 *
+	 * @return true If a new session directory was created, otherwise
+	 * (if it already existed) false.
+	 *
+	 * @post is_valid ()
 	 */
 	bool create ();
 
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 1fa5d47ac0..3f1760c88a 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -133,23 +133,48 @@ Session::Session (AudioEngine &eng,
 
 	SessionDirectory sdir(fullpath);
 
-	if (mix_template &&
-		sdir.create() &&
-		create_session_file_from_template (*mix_template)) {
+	if(mix_template) {
+		// try and create a new session directory
+		try
+		{
+			if(!sdir.create()) {
+				// an existing session.
+				// throw a_more_meaningful_exception()
+				destroy ();
+				throw failed_constructor ();
+			}
+		}
+		catch(sys::filesystem_error& ex)
+		{
+			destroy ();
+			throw failed_constructor ();
+		}
+
+		if(!create_session_file_from_template (*mix_template)) {
+			destroy ();
+			throw failed_constructor ();
+		}
 
 		cerr << "Creating session " << fullpath
 			<<" using template" << *mix_template
 			<< endl;
-
-	} else if (sdir.is_valid ()) {
+	} else {
+		// must be an existing session
+		try
+		{
+			// ensure the necessary session subdirectories exist
+			// in case the directory structure has changed etc.
+			sdir.create();
+		}
+		catch(sys::filesystem_error& ex)
+		{
+			destroy ();
+			throw failed_constructor ();
+		}
 
 		cerr << "Loading session " << fullpath
 			<< " using snapshot " << snapshot_name << " (1)"
 			<< endl;
-
-	} else {
-		destroy ();
-		throw failed_constructor ();
 	}
 
 	if (second_stage_init (false)) {
diff --git a/libs/ardour/session_directory.cc b/libs/ardour/session_directory.cc
index e871b84244..91b2587eb7 100644
--- a/libs/ardour/session_directory.cc
+++ b/libs/ardour/session_directory.cc
@@ -43,23 +43,29 @@ SessionDirectory::SessionDirectory (const string& session_path)
 bool
 SessionDirectory::create ()
 {
-	if (is_directory (m_root_path))
-	{
-		PBD::error << string_compose(_("Cannot create Session directory at path %1 as it already exists"), m_root_path.to_string()) << endmsg;
-		return false;
-	}
+	bool is_new = false;
 
 	vector<path> sub_dirs = sub_directories ();
 	for (vector<path>::const_iterator i = sub_dirs.begin(); i != sub_dirs.end(); ++i)
 	{
-		if (!create_directories(*i))
+		try
 		{
-			PBD::error << string_compose(_("Cannot create Session directory at path %1 Error: %2"), (*i).to_string(), g_strerror (errno)) << endmsg;
-			return false;
+			if(create_directories(*i)) {
+				PBD::info << string_compose(_("Created Session directory at path %1"), (*i).to_string()) << endmsg;
+				is_new = true;
+			}
+		}
+		catch (PBD::sys::filesystem_error& ex)
+		{
+			// log the error
+			PBD::error << string_compose(_("Cannot create Session directory at path %1 Error: %2"), (*i).to_string(), ex.what()) << endmsg;
+
+			// and rethrow
+			throw ex;
 		}
 	}
 
-	return true;
+	return is_new;
 }
 
 bool
diff --git a/libs/pbd/filesystem.cc b/libs/pbd/filesystem.cc
index f376fa72f0..229b22fcb5 100644
--- a/libs/pbd/filesystem.cc
+++ b/libs/pbd/filesystem.cc
@@ -21,6 +21,8 @@
 #include <glib.h>
 #include <glib/gstdio.h>
 
+#include <cerrno>
+
 #include <glibmm/fileutils.h>
 #include <glibmm/miscutils.h>
 
@@ -67,24 +69,28 @@ is_directory (const path & p)
 bool
 create_directory(const path & p)
 {
-	if (g_mkdir (p.to_string().c_str(), S_IRWXU|S_IRWXG|S_IRWXO) != 0)
+	if(is_directory(p)) return false;
+
+	int error = g_mkdir (p.to_string().c_str(), S_IRWXU|S_IRWXG|S_IRWXO);
+
+	if(error == -1)
 	{
-		warning << "Unable to create directory at path: " << p.to_string() << endmsg;
-		return false;
+		throw filesystem_error(g_strerror(errno), errno);
 	}
-
 	return true;
 }
 
 bool
 create_directories(const path & p)
 {
-	if (g_mkdir_with_parents (p.to_string().c_str(), S_IRWXU|S_IRWXG|S_IRWXO) != 0)
+	if(is_directory(p)) return false;
+
+	int error = g_mkdir_with_parents (p.to_string().c_str(), S_IRWXU|S_IRWXG|S_IRWXO);
+
+	if(error == -1)
 	{
-		warning << "Unable to create directory at path: " << p.to_string() << endmsg;
-		return false;
+		throw filesystem_error(g_strerror(errno), errno);
 	}
-
 	return true;
 }
 
diff --git a/libs/pbd/pbd/filesystem.h b/libs/pbd/pbd/filesystem.h
index 11d62be632..8d4bf8dea9 100644
--- a/libs/pbd/pbd/filesystem.h
+++ b/libs/pbd/pbd/filesystem.h
@@ -19,6 +19,7 @@
 #ifndef __filesystem_h__
 #define __filesystem_h__
 
+#include <stdexcept>
 #include <string>
 
 namespace PBD {
@@ -50,11 +51,47 @@ private:
 	string m_path;
 };
 
+class filesystem_error : public std::runtime_error
+{
+	const int m_error_code;
+
+public:
+	explicit filesystem_error(const std::string & what, int error_code=0)
+		: std::runtime_error(what), m_error_code(error_code) { }
 
+	int system_error() const { return m_error_code; }
+};
+
+/// @return true if path at p exists
 bool exists(const path & p);
+
+/// @return true if path at p is a directory.
 bool is_directory(const path & p);
 
+/**
+ * Attempt to create a directory at p as if by the glib function g_mkdir 
+ * with a second argument of S_IRWXU|S_IRWXG|S_IRWXO
+ * 
+ * @throw filesystem_error if mkdir fails for any other reason other than
+ * the directory already exists.
+ *
+ * @return true If the directory p was created, otherwise false
+ *
+ * @post is_directory(p)
+ */
 bool create_directory(const path & p);
+
+/**
+ * Attempt to create a directory at p as if by the glib function 
+ * g_mkdir_with_parents with a second argument of S_IRWXU|S_IRWXG|S_IRWXO
+ * 
+ * @throw filesystem_error if g_mkdir_with_parents fails for any other 
+ * reason other than the directory already exists.
+ *
+ * @return true If the directory at p was created, otherwise false
+ *
+ * @post is_directory(p)
+ */
 bool create_directories(const path & p);
 
 string basename (const path& p);