feat(translator): add history_translator (#115)

* feat(translator): add history_translator

* chore(history_translator): remove default value and align continued line to open parenthesis

* chore(history_translator): bring back some default values

include/rime/gear/history_translator.h

@@ -0,0 +1,30 @@
+//
+// Copyright RIME Developers
+// Distributed under the BSD License
+//
+// 2016-09-08 osfans <waxaca@163.com>
+//
+#ifndef RIME_HISTORY_TRANSLATOR_H_
+#define RIME_HISTORY_TRANSLATOR_H_
+
+#include <rime/translator.h>
+
+namespace rime {
+
+class HistoryTranslator : public Translator {
+ public:
+  HistoryTranslator(const Ticket& ticket);
+
+  virtual an<Translation> Query(const string& input,
+                                const Segment& segment);
+
+ protected:
+  string tag_;
+  string input_;
+  int size_;
+  double initial_quality_;
+};
+
+}  // namespace rime
+
+#endif  // RIME_HISTORY_TRANSLATOR_H_

src/gear/gears_module.cc

@@ -36,6 +36,7 @@
 #include <rime/gear/table_translator.h>
 #include <rime/gear/uniquifier.h>
 #include <rime/gear/codepoint_translator.h>
+#include <rime/gear/history_translator.h>
 
 static void rime_gears_initialize() {
   using namespace rime;
@@ -76,6 +77,7 @@ static void rime_gears_initialize() {
   r.Register("schema_list_translator", new Component<SchemaListTranslator>);
   r.Register("switch_translator", new Component<SwitchTranslator>);
   r.Register("codepoint_translator", new Component<CodepointTranslator>);
+  r.Register("history_translator", new Component<HistoryTranslator>);
 
   // filters
   r.Register("simplifier", new Component<Simplifier>);

src/gear/history_translator.cc

@@ -0,0 +1,63 @@
+//
+// Copyright RIME Developers
+// Distributed under the BSD License
+//
+// 2016-09-08 osfans <waxaca@163.com>
+//
+
+#include <rime/candidate.h>
+#include <rime/context.h>
+#include <rime/engine.h>
+#include <rime/schema.h>
+#include <rime/ticket.h>
+#include <rime/translation.h>
+#include <rime/gear/history_translator.h>
+
+namespace rime {
+
+HistoryTranslator::HistoryTranslator(const Ticket& ticket)
+    : Translator(ticket),
+      tag_("abc"),
+      size_(1),
+      initial_quality_(1000) {
+  if (ticket.name_space == "translator") {
+    name_space_ = "history";
+  }
+  if (!ticket.schema)
+    return;
+  Config* config = ticket.schema->config();
+  config->GetString(name_space_ + "/tag", &tag_);
+  config->GetString(name_space_ + "/input", &input_);
+  config->GetInt(name_space_ + "/size", &size_);
+  config->GetDouble(name_space_ + "/initial_quality",
+                    &initial_quality_);
+}
+
+an<Translation> HistoryTranslator::Query(const string& input,
+                                         const Segment& segment) {
+  if (!segment.HasTag(tag_))
+    return nullptr;
+  if (input_.empty() || input_ != input)
+    return nullptr;
+
+  const auto& history(engine_->context()->commit_history());
+  if (history.empty())
+    return nullptr;
+  auto translation = New<FifoTranslation>();
+  auto it = history.rbegin();
+  int count = 0;
+  for (; it != history.rend(); ++it) {
+    if (it->type == "thru") continue;
+    auto candidate = New<SimpleCandidate>(it->type,
+                                          segment.start,
+                                          segment.end,
+                                          it->text);
+    candidate->set_quality(initial_quality_);
+    translation->Append(candidate);
+    count++;
+    if (size_ == count) break;
+  }
+  return translation;
+}
+
+}  // namespace rime