Added new option --inject=KEY[,KEY...]

If you have a typed metadata key which contains an amount, you can use
--inject=KEY to inject a posting with that amount wherever a match
occurs.  There are two main forms of usage:

  2010-06-18 Sample
      ; Key:: $100
      Expenses:Food                $100.00
      Assets:Checking

The command would be:

  ledger reg --inject=Key

In the above, transactional form, a posting under the account "Key" will
be injected before the first posting reported for this transaction.
It's amount will be $100.  This only happens once for the whole
transaction.

It is also possible to associate the key with a posting:

  2010-06-18 Sample
      Expenses:Food                $100.00
      ; Key:: $100
      Assets:Checking

Now the injected posting is generated whenever that particular post is
reported.

7 files changed, 89 insertions, 1 deletions

diff --git a/doc/ledger.1 b/doc/ledger.1
index 4e72c792..ba4317f9 100644
--- a/doc/ledger.1
+++ b/doc/ledger.1
@@ -1,4 +1,4 @@
-.Dd June 15, 2010
+.Dd June 18, 2010
 .Dt ledger 1
 .Sh NAME
 .Nm ledger
@@ -336,6 +336,7 @@ See
 .It Fl \-help-disp
 .It Fl \-import Ar STR
 .It Fl \-init-file Ar FILE
+.It Fl \-inject Ar STR
 .It Fl \-input-date-format Ar DATEFMT
 .It Fl \-invert
 .It Fl \-last Ar INT
diff --git a/src/chain.cc b/src/chain.cc
index 64550663..8010ba74 100644
--- a/src/chain.cc
+++ b/src/chain.cc
@@ -258,6 +258,10 @@ post_handler_ptr chain_post_handlers(post_handler_ptr base_handler,
   if (report.HANDLED(related))
     handler.reset(new related_posts(handler, report.HANDLED(related_all)));
 
+  if (report.HANDLED(inject_))
+    handler.reset(new inject_posts(handler, report.HANDLED(inject_).str(),
+                                   report.session.journal->master));
+
   return handler;
 }
 
diff --git a/src/filters.cc b/src/filters.cc
index 6e832149..33905856 100644
--- a/src/filters.cc
+++ b/src/filters.cc
@@ -1338,6 +1338,66 @@ void forecast_posts::flush()
   item_handler<post_t>::flush();
 }
 
+inject_posts::inject_posts(post_handler_ptr handler,
+                           const string&    tag_list,
+                           account_t *      master)
+  : item_handler<post_t>(handler)
+{
+  TRACE_CTOR(inject_posts, "post_handler_ptr, string");
+
+  scoped_array<char> buf(new char[tag_list.length() + 1]);
+  std::strcpy(buf.get(), tag_list.c_str());
+
+  for (char * q = std::strtok(buf.get(), ",");
+       q;
+       q = std::strtok(NULL, ",")) {
+
+    std::list<string> account_names;
+    split_string(q, ':', account_names);
+    account_t * account =
+      create_temp_account_from_path(account_names, temps, master);
+    account->add_flags(ACCOUNT_GENERATED);
+
+    tags_list.push_back
+      (tags_list_pair(q, tag_mapping_pair(account, tag_injected_set())));
+  }
+}
+
+void inject_posts::operator()(post_t& post)
+{
+  foreach (tags_list_pair& pair, tags_list) {
+    optional<value_t> tag_value = post.get_tag(pair.first, false);
+    if (! tag_value &&
+        pair.second.second.find(post.xact) == pair.second.second.end()) {
+      // When checking if the transaction has the tag, only inject once
+      // per transaction.
+      pair.second.second.insert(post.xact);
+      tag_value = post.xact->get_tag(pair.first);
+    }
+
+    if (tag_value) {
+      if (tag_value->is_amount()) {
+        xact_t& xact = temps.copy_xact(*post.xact);
+        xact._date = post.date();
+        xact.add_flags(ITEM_GENERATED);
+        post_t& temp = temps.copy_post(post, xact);
+
+        temp.account = pair.second.first;
+        temp.amount  = tag_value->as_amount();
+        temp.add_flags(ITEM_GENERATED);
+
+        item_handler<post_t>::operator()(temp);
+      } else {
+        throw_(std::logic_error,
+               _("Attempt to inject a posting with non-amount %1 for tag %2")
+               << *tag_value << pair.first);
+      }
+    }
+  }
+
+  item_handler<post_t>::operator()(post);
+}
+
 pass_down_accounts::pass_down_accounts(acct_handler_ptr             handler,
                                        accounts_iterator&           iter,
                                        const optional<predicate_t>& _pred,
diff --git a/src/filters.h b/src/filters.h
index 9102d4f1..180253d2 100644
--- a/src/filters.h
+++ b/src/filters.h
@@ -929,6 +929,26 @@ class forecast_posts : public generate_posts
   }
 };
 
+class inject_posts : public item_handler<post_t>
+{
+  typedef std::set<xact_t *>                       tag_injected_set;
+  typedef std::pair<account_t *, tag_injected_set> tag_mapping_pair;
+  typedef std::pair<string, tag_mapping_pair>      tags_list_pair;
+
+  std::list<tags_list_pair> tags_list;
+  temporaries_t             temps;
+
+ public:
+  inject_posts(post_handler_ptr handler, const string& tag_list,
+               account_t * master);
+
+  virtual ~inject_posts() throw() {
+    TRACE_DTOR(inject_posts);
+  }
+
+  virtual void operator()(post_t& post);
+};
+
 //////////////////////////////////////////////////////////////////////
 //
 // Account filters
diff --git a/src/report.cc b/src/report.cc
index 9626283a..da7c11f5 100644
--- a/src/report.cc
+++ b/src/report.cc
@@ -955,6 +955,7 @@ option_t<report_t> * report_t::lookup_option(const char * p)
     break;
   case 'i':
     OPT(invert);
+    else OPT(inject_);
     break;
   case 'j':
     OPT_CH(amount_data);
diff --git a/src/report.h b/src/report.h
index a453d351..7d725b8c 100644
--- a/src/report.h
+++ b/src/report.h
@@ -260,6 +260,7 @@ public:
     HANDLER(group_by_).report(out);
     HANDLER(group_title_format_).report(out);
     HANDLER(head_).report(out);
+    HANDLER(inject_).report(out);
     HANDLER(invert).report(out);
     HANDLER(limit_).report(out);
     HANDLER(lot_dates).report(out);
@@ -616,6 +617,7 @@ public:
     });
 
   OPTION(report_t, head_);
+  OPTION(report_t, inject_);
 
   OPTION_(report_t, invert, DO() {
       parent->HANDLER(amount_).set_expr(string("--invert"), "-amount");
diff --git a/test/baseline/opt-inject.test b/test/baseline/opt-inject.test
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/test/baseline/opt-inject.test