Add complete_command for completing commands in PATH

use it for pipe completion

src/file.cc

@@ -251,13 +251,54 @@ String find_file(const String& filename, memoryview<String> paths)
     return "";
 }
 
+template<typename Filter>
+std::vector<String> list_files(const String& prefix,
+                               const String& dirname,
+                               Filter filter)
+{
+    kak_assert(dirname.empty() or dirname.back() == '/');
+    DIR* dir = opendir(dirname.empty() ? "./" : dirname.c_str());
+    auto closeDir = on_scope_end([=]{ closedir(dir); });
+
+    std::vector<String> result;
+    if (not dir)
+        return result;
+
+    std::vector<String> subseq_result;
+    while (dirent* entry = readdir(dir))
+    {
+        if (not filter(*entry))
+            continue;
+
+        String filename = entry->d_name;
+        if (filename.empty())
+            continue;
+
+        const bool match_prefix = prefix_match(filename, prefix);
+        const bool match_subseq = subsequence_match(filename, prefix);
+        if (match_prefix or match_subseq)
+        {
+            if (entry->d_type == DT_DIR)
+                filename += '/';
+            if (prefix.length() != 0 or filename[0] != '.')
+            {
+                if (match_prefix)
+                    result.push_back(filename);
+                if (match_subseq)
+                    subseq_result.push_back(filename);
+            }
+        }
+    }
+    auto& real_result = result.empty() ? subseq_result : result;
+    return real_result;
+}
+
 std::vector<String> complete_filename(const String& prefix,
                                       const Regex& ignored_regex,
                                       ByteCount cursor_pos)
 {
     String real_prefix = parse_filename(prefix.substr(0, cursor_pos));
-    String dirname = "./";
+    String dirname;
-    String dirprefix;
     String fileprefix = real_prefix;
 
     ByteCount dir_end = -1;
@@ -269,49 +310,68 @@ std::vector<String> complete_filename(const String& prefix,
     if (dir_end != -1)
     {
         dirname = real_prefix.substr(0, dir_end + 1);
-        dirprefix = dirname;
         fileprefix = real_prefix.substr(dir_end + 1);
     }
 
-    DIR* dir = opendir(dirname.c_str());
-    auto closeDir = on_scope_end([=]{ closedir(dir); });
-
-    std::vector<String> result;
-    if (not dir)
-        return result;
-
     const bool check_ignored_regex = not ignored_regex.empty() and
         not boost::regex_match(fileprefix.c_str(), ignored_regex);
 
-    std::vector<String> subseq_result;
+    auto filter = [&](const dirent& entry)
-    while (dirent* entry = readdir(dir))
     {
-        String filename = entry->d_name;
+        return not check_ignored_regex or
-        if (filename.empty())
+               not boost::regex_match(entry.d_name, ignored_regex);
-            continue;
+    };
+    std::vector<String> res = list_files(fileprefix, dirname, filter);
+    for (auto& file : res)
+        file = escape(dirname + file);
+    std::sort(res.begin(), res.end());
+    return res;
+}
 
-        if (check_ignored_regex and boost::regex_match(filename.c_str(), ignored_regex))
+std::vector<String> complete_command(const String& prefix, ByteCount cursor_pos)
-            continue;
+{
+    String real_prefix = parse_filename(prefix.substr(0, cursor_pos));
+    String dirname;
+    String fileprefix = real_prefix;
 
-        const bool match_prefix = prefix_match(filename, fileprefix);
+    ByteCount dir_end = -1;
-        const bool match_subseq = subsequence_match(filename, fileprefix);
+    for (ByteCount i = 0; i < real_prefix.length(); ++i)
-        if (match_prefix or match_subseq)
     {
-            String name = dirprefix + filename;
+        if (real_prefix[i] == '/')
-            if (entry->d_type == DT_DIR)
+            dir_end = i;
-                name += '/';
+    }
-            if (fileprefix.length() != 0 or filename[0] != '.')
+
+    std::vector<String> path;
+    if (dir_end != -1)
     {
-                if (match_prefix)
+        path.emplace_back(real_prefix.substr(0, dir_end + 1));
-                    result.push_back(escape(name));
+        fileprefix = real_prefix.substr(dir_end + 1);
-                if (match_subseq)
-                    subseq_result.push_back(escape(name));
     }
+    else
+        path = split(getenv("PATH"), ':');
+
+    std::vector<String> res;
+    for (auto dirname : path)
+    {
+        if (not dirname.empty() and dirname.back() != '/')
+            dirname += '/';
+
+        auto filter = [&](const dirent& entry) {
+            struct stat st;
+            if (stat((dirname + entry.d_name).c_str(), &st))
+                return false;
+            bool executable = (st.st_mode & S_IXUSR)
+                            | (st.st_mode & S_IXGRP)
+                            | (st.st_mode & S_IXOTH);
+            return S_ISREG(st.st_mode) and executable;
+        };
+        auto completion = list_files(prefix, dirname, filter);
+        std::move(completion.begin(), completion.end(), std::back_inserter(res));
     }
-    }
+    std::sort(res.begin(), res.end());
-    auto& real_result = result.empty() ? subseq_result : result;
+    auto it = std::unique(res.begin(), res.end());
-    std::sort(real_result.begin(), real_result.end());
+    res.erase(it, res.end());
-    return real_result;
+    return res;
 }
 
 time_t get_fs_timestamp(const String& filename)

src/file.hh

@@ -38,6 +38,9 @@ time_t get_fs_timestamp(const String& filename);
 std::vector<String> complete_filename(const String& prefix,
                                       const Regex& ignore_regex,
                                       ByteCount cursor_pos = -1);
+
+std::vector<String> complete_command(const String& prefix,
+                                      ByteCount cursor_pos = -1);
 }
 
 #endif // file_hh_INCLUDED

src/normal.cc

@@ -420,7 +420,37 @@ void command(Context& context, int)
 
 void pipe(Context& context, int)
 {
-    context.input_handler().prompt("pipe:", get_color("Prompt"), complete_nothing,
+    auto completer = [](const Context& context, CompletionFlags flags,
+                        const String& prefix, ByteCount cursor_pos)
+    {
+        ByteCount word_start = 0;
+        ByteCount word_end = 0;
+
+        bool first = true;
+        const ByteCount len = prefix.length();
+        for (ByteCount pos = 0; pos < cursor_pos;)
+        {
+            if (pos != 0)
+                first = false;
+            while (pos != len and is_blank(prefix[pos]))
+                ++pos;
+            word_start = pos;
+            while (pos != len and not is_blank(prefix[pos]))
+                ++pos;
+            word_end = pos;
+        }
+        Completions completions{word_start, word_end};
+        if (first)
+            completions.candidates = complete_command(prefix.substr(word_start, word_end),
+                                                      cursor_pos - word_start);
+        else
+            completions.candidates = complete_filename(prefix.substr(word_start, word_end),
+                                                       context.options()["ignored_files"].get<Regex>(), 
+                                                       cursor_pos - word_start);
+        return completions;
+    };
+
+    context.input_handler().prompt("pipe:", get_color("Prompt"), completer,
         [](const String& cmdline, PromptEvent event, Context& context)
         {
             if (event != PromptEvent::Validate)