Added a facility for handling scoped executions.

4 files changed, 94 insertions, 44 deletions

diff --git a/src/scoped_execute.h b/src/scoped_execute.h
new file mode 100644
index 00000000..da3f388e
--- /dev/null
+++ b/src/scoped_execute.h
@@ -0,0 +1,73 @@
+#ifndef _SCOPE_EXECUTE_H
+#define _SCOPE_EXECUTE_H
+
+template <typename T>
+class scoped_variable : public boost::noncopyable
+{
+  T&   var;
+  T    prev;
+  bool enabled;
+
+public:
+  explicit scoped_variable(T& _var)
+    : var(_var), prev(var), enabled(true) {}
+  explicit scoped_variable(T& _var, const T& value)
+    : var(_var), prev(var), enabled(true) {
+    var = value;
+  }
+  ~scoped_variable() {
+    if (enabled)
+      var = prev;
+  }
+
+  void clear() {
+    enabled = false;
+  }
+};
+
+template <typename T>
+class scoped_execute : public boost::noncopyable
+{
+  typedef boost::function<void (T)> function_t;
+
+  function_t code;
+  T	     arg;
+  bool       enabled;
+
+public:
+  explicit scoped_execute(const function_t& _code, T _arg)
+    : code(_code), arg(_arg), enabled(true) {}
+
+  ~scoped_execute() {
+    if (enabled)
+      code(arg);
+  }
+
+  void clear() {
+    enabled = false;
+  }
+};
+
+template <>
+class scoped_execute<void> : public boost::noncopyable
+{
+  typedef boost::function<void ()> function_t;
+
+  function_t code;
+  bool       enabled;
+
+public:
+  explicit scoped_execute(const function_t& _code)
+    : code(_code), enabled(true) {}
+
+  ~scoped_execute() {
+    if (enabled)
+      code();
+  }
+
+  void clear() {
+    enabled = false;
+  }
+};
+
+#endif // _SCOPE_EXECUTE_H
diff --git a/src/session.cc b/src/session.cc
index d53faf09..1477139c 100644
--- a/src/session.cc
+++ b/src/session.cc
@@ -103,22 +103,13 @@ journal_t * session_t::read_data(const string& master_account)
     DEBUG("ledger.cache", "using_cache " << cache_file->string());
     cache_dirty = true;
     if (exists(*cache_file)) {
-      ifstream stream(*cache_file);
-
-      optional<path> price_db_orig = journal->price_db;
-      try {
-	journal->price_db = price_db;
-
-	entry_count += read_journal(stream, journal, NULL, data_file);
-	if (entry_count > 0)
-	  cache_dirty = false;
+      scoped_variable<optional<path> >
+	save_price_db(journal->price_db, price_db);
 
-	journal->price_db = price_db_orig;
-      }
-      catch (...) {
-	journal->price_db = price_db_orig;
-	throw;
-      }
+      ifstream stream(*cache_file);
+      entry_count += read_journal(stream, journal, NULL, data_file);
+      if (entry_count > 0)
+	cache_dirty = false;
     }
   }
 
diff --git a/src/textual.cc b/src/textual.cc
index 8ed83698..5c2dd81d 100644
--- a/src/textual.cc
+++ b/src/textual.cc
@@ -10,7 +10,8 @@ static unsigned int linenum;
 static unsigned int src_idx;
 static accounts_map account_aliases;
 
-static std::list<std::pair<path, int> > include_stack;
+typedef std::list<std::pair<path, int> > include_stack_t;
+static include_stack_t include_stack;
 
 #define TIMELOG_SUPPORT 1
 #ifdef TIMELOG_SUPPORT
@@ -508,14 +509,6 @@ entry_t * parse_entry(std::istream& in, char * line, journal_t * journal,
   return curr.release();
 }
 
-template <typename T>
-struct push_var {
-  T& var;
-  T prev;
-  push_var(T& _var) : var(_var), prev(var) {}
-  ~push_var() { var = prev; }
-};
-
 static inline void parse_symbol(char *& p, string& symbol)
 {
   if (*p == '"') {
@@ -836,11 +829,11 @@ unsigned int textual_parser_t::parse(std::istream&	   in,
       char * p = next_element(line);
       string word(line + 1);
       if (word == "include") {
-	push_var<path>		save_path(pathname);
-	push_var<unsigned int>  save_src_idx(src_idx);
-	push_var<unsigned long> save_beg_pos(beg_pos);
-	push_var<unsigned long> save_end_pos(end_pos);
-	push_var<unsigned int>  save_linenum(linenum);
+	scoped_variable<path>	       save_path(pathname);
+	scoped_variable<unsigned int>  save_src_idx(src_idx);
+	scoped_variable<unsigned long> save_beg_pos(beg_pos);
+	scoped_variable<unsigned long> save_end_pos(end_pos);
+	scoped_variable<unsigned int>  save_linenum(linenum);
 
 	if (*p != '~' && *p != '/')
 	  pathname = (pathname.branch_path() / path(p)).normalize();
@@ -850,18 +843,14 @@ unsigned int textual_parser_t::parse(std::istream&	   in,
 	DEBUG("ledger.textual.include", "Line " << linenum << ": " <<
 	      "Including path '" << pathname.string() << "'");
 
+	scoped_execute<void>
+	  pop_include_stack(boost::bind(&include_stack_t::pop_back,
+					boost::ref(include_stack)));
 	include_stack.push_back
 	  (std::pair<path, int>(journal->sources.back(), linenum - 1));
 
-	try {
-	  count += journal->session->read_journal(pathname, journal,
-						  account_stack.front());
-	  include_stack.pop_back();
-	}
-	catch (...) {
-	  include_stack.pop_back();
-	  throw;
-	}
+	count += journal->session->read_journal(pathname, journal,
+						account_stack.front());
       }
       else if (word == "account") {
 	if (account_t * acct = account_stack.front()->find_account(p))
diff --git a/src/utils.h b/src/utils.h
index 22fc48dc..a3ef8d39 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -441,16 +441,13 @@ inline void throw_unexpected_error(char c, char wanted) {
 /**********************************************************************
  *
  * Date/time support classes
- */
-
-#include "times.h"
-
-/**********************************************************************
- *
  * General support for objects with "flags"
+ * Support for scoped execution and variable restoration
  */
 
+#include "times.h"
 #include "flags.h"
+#include "scoped_execute.h"
 
 /**********************************************************************
  *