More options for completion filtering

.gitmodules

@@ -19,3 +19,6 @@
 [submodule "third_party/reproc"]
 	path = third_party/reproc
 	url = https://github.com/DaanDeMeyer/reproc.git
+[submodule "third_party/lib_fts"]
+	path = third_party/lib_fts
+	url = https://github.com/forrestthewoods/lib_fts.git

CMakeLists.txt

@@ -156,6 +156,7 @@ target_include_directories(cquery PRIVATE
   third_party/pugixml/src
   third_party/rapidjson/include
   third_party/sparsepp
+  third_party/lib_fts/code
 )
 
 ### Install
@@ -304,6 +305,8 @@ target_sources(cquery PRIVATE
   src/file_contents.cc
   src/file_types.cc
   src/fuzzy_match.cc
+  src/fts_match.cc
+  src/prefix_match.cc
   src/iindexer.cc
   src/import_manager.cc
   src/import_pipeline.cc

src/completion_matcher.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#include <string_view.h>
+
+class CompletionMatcher {
+ public:
+  // virtual ~CompletionMatcher() = default; // don't know why but it crashed if I uncomment this like, investigating
+  virtual int Match(std::string_view text) = 0;
+  virtual int MinScore() const = 0;
+};

src/config.h

@@ -156,6 +156,9 @@ struct Config {
     // For example, to hide all files in a /CACHE/ folder, use ".*/CACHE/.*"
     std::vector<std::string> includeBlacklist;
     std::vector<std::string> includeWhitelist;
+
+    //
+    std::string matcherType = "cqueryMatcher";
   };
   Completion completion;
 
@@ -261,7 +264,8 @@ MAKE_REFLECT_STRUCT(Config::Completion,
                     includeMaxPathSize,
                     includeSuffixWhitelist,
                     includeBlacklist,
-                    includeWhitelist);
+                    includeWhitelist,
+                    matcherType);
 MAKE_REFLECT_STRUCT(Config::Formatting, enabled)
 MAKE_REFLECT_STRUCT(Config::Diagnostics,
                     blacklist,

src/fts_match.cc

@@ -0,0 +1,23 @@
+#include "fts_match.h"
+
+#define FTS_FUZZY_MATCH_IMPLEMENTATION 1
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-function"
+#include <fts_fuzzy_match.h>
+#pragma clang diagnostic pop
+
+FtsMatcher::FtsMatcher(std::string_view pattern) {
+  original_pattern = pattern;
+}
+
+int FtsMatcher::Match(std::string_view text) {
+  int result = 0;
+  if (fts::fuzzy_match(original_pattern.data(), text.data(), result)) {
+    return result;
+  }
+  return MinScore();
+}
+
+int FtsMatcher::MinScore() const {
+  return -100000;
+}

src/fts_match.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include "completion_matcher.h"
+
+class FtsMatcher : public CompletionMatcher {
+ public:
+  FtsMatcher(std::string_view pattern);
+  int Match(std::string_view text) override;
+  int MinScore() const override;
+
+ private:
+  std::string_view original_pattern;
+};

src/fuzzy_match.cc

@@ -6,6 +6,7 @@
 #include <stdio.h>
 #include <algorithm>
 #include <vector>
+#include "lex_utils.h"
 
 enum CharClass { Other, Lower, Upper };
 enum CharRole { None, Tail, Head };
@@ -73,6 +74,7 @@ int FuzzyMatcher::MatchScore(int i, int j, bool last) {
 }
 
 FuzzyMatcher::FuzzyMatcher(std::string_view pattern) {
+  original_pattern = pattern;
   CalculateRoles(pattern, pat_role, &pat_set);
   size_t n = 0;
   for (size_t i = 0; i < pattern.size(); i++)
@@ -85,6 +87,9 @@ FuzzyMatcher::FuzzyMatcher(std::string_view pattern) {
 }
 
 int FuzzyMatcher::Match(std::string_view text) {
+  if (!CaseFoldingSubsequenceMatch(original_pattern, text).first) {
+    return MinScore();
+  }
   int n = int(text.size());
   if (n > kMaxText)
     return kMinScore + 1;
@@ -123,6 +128,10 @@ int FuzzyMatcher::Match(std::string_view text) {
   return ret;
 }
 
+int FuzzyMatcher::MinScore() const {
+  return kMinScore;
+}
+
 TEST_SUITE("fuzzy_match") {
   bool Ranks(std::string_view pat, std::vector<const char*> texts) {
     FuzzyMatcher fuzzy(pat);

src/fuzzy_match.h

@@ -4,8 +4,9 @@
 
 #include <limits.h>
 #include <string>
+#include "completion_matcher.h"
 
-class FuzzyMatcher {
+class FuzzyMatcher : public CompletionMatcher {
  public:
   constexpr static int kMaxPat = 100;
   constexpr static int kMaxText = 200;
@@ -14,9 +15,11 @@ class FuzzyMatcher {
   constexpr static int kMinScore = INT_MIN / 4;
 
   FuzzyMatcher(std::string_view pattern);
-  int Match(std::string_view text);
+  int Match(std::string_view text) override;
+  int MinScore() const override;
 
  private:
+  std::string_view original_pattern;
   std::string pat;
   std::string_view text;
   int pat_set, text_set;

src/messages/text_document_completion.cc

@@ -1,11 +1,14 @@
 #include "clang_complete.h"
 #include "code_complete_cache.h"
 #include "fuzzy_match.h"
+#include "fts_match.h"
+#include "prefix_match.h"
 #include "include_complete.h"
 #include "message_handler.h"
 #include "queue_manager.h"
 #include "timer.h"
 #include "working_files.h"
+#include "config.h"
 
 #include "lex_utils.h"
 
@@ -221,17 +224,23 @@ void FilterAndSortCompletionResponse(
       item.filterText = item.label;
   }
 
-  // Fuzzy match and remove awful candidates.
-  FuzzyMatcher fuzzy(complete_text);
+  // Match and remove awful candidates.
+  std::unique_ptr<CompletionMatcher> matcher;
+  if (g_config->completion.matcherType == "cqueryMatcher") {
+    matcher = std::make_unique<FuzzyMatcher>(complete_text);
+  } else if (g_config->completion.matcherType == "ftsMatcher") {
+    matcher = std::make_unique<FtsMatcher>(complete_text);
+  } else if (g_config->completion.matcherType == "caseSensitivePrefixMatcher") {
+    matcher = std::make_unique<PrefixMatcher>(complete_text, true);
+  } else if (g_config->completion.matcherType == "caseInsensitivePrefixMatcher") {
+    matcher = std::make_unique<PrefixMatcher>(complete_text, false);
+  }
   for (auto& item : items) {
-    item.score_ =
-        CaseFoldingSubsequenceMatch(complete_text, *item.filterText).first
-            ? fuzzy.Match(*item.filterText)
-            : FuzzyMatcher::kMinScore;
+    item.score_ = matcher->Match(*item.filterText);
   }
   items.erase(std::remove_if(items.begin(), items.end(),
-                             [](const lsCompletionItem& item) {
-                               return item.score_ <= FuzzyMatcher::kMinScore;
+                             [&matcher](const lsCompletionItem& item) {
+                               return item.score_ <= matcher->MinScore();
                              }),
               items.end());
   std::sort(items.begin(), items.end(),

src/prefix_match.cc

@@ -0,0 +1,39 @@
+#include "prefix_match.h"
+
+#include <algorithm>
+#include <cctype>
+
+namespace {
+    bool StartsWith(std::string_view text, std::string_view prefix) {
+      return text.find(prefix) == 0;
+    }
+
+    bool StartsWithIgnoreCase(std::string_view text, std::string_view prefix) {
+      auto min_length = std::min(text.size(), prefix.size());
+      if (min_length == 0) {
+        return false;
+      }
+      return std::equal(
+          text.begin(), text.begin() + min_length,
+          prefix.begin(), prefix.begin() + min_length,
+          [](char ch1, char ch2) { return std::toupper(ch1) == std::toupper(ch2); }
+          );
+    }
+}
+
+PrefixMatcher::PrefixMatcher(std::string_view pattern, bool case_sensitive) {
+  original_pattern = pattern;
+  this->case_sensitive = case_sensitive;
+}
+
+int PrefixMatcher::Match(std::string_view text) {
+  if (case_sensitive) {
+    return ::StartsWith(text, original_pattern) ? 1 : MinScore();
+  } else {
+    return ::StartsWithIgnoreCase(text, original_pattern) ? 1 : MinScore();
+  }
+}
+
+int PrefixMatcher::MinScore() const {
+  return -1;
+}

src/prefix_match.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "completion_matcher.h"
+
+class PrefixMatcher : public CompletionMatcher {
+ public:
+  PrefixMatcher(std::string_view pattern, bool case_sensitive);
+  int Match(std::string_view text) override;
+  int MinScore() const override;
+
+ private:
+  std::string_view original_pattern;
+  bool case_sensitive;
+};