Store timespec for buffer fs timestamps, not just time_t

time_t has a resolution of one second, which cause troubles when
a file changes multiple time during that same second.

7 files changed, 33 insertions, 23 deletions

diff --git a/src/buffer.cc b/src/buffer.cc
index 0685e5b3..02f076d0 100644
--- a/src/buffer.cc
+++ b/src/buffer.cc
@@ -18,7 +18,7 @@ namespace Kakoune
 {
 
 Buffer::Buffer(String name, Flags flags, BufferLines lines,
-               time_t fs_timestamp)
+               timespec fs_timestamp)
     : Scope(GlobalScope::instance()),
       m_name((flags & Flags::File) ? real_path(parse_filename(name)) : std::move(name)),
       m_display_name((flags & Flags::File) ? compact_path(m_name) : m_name),
@@ -160,7 +160,7 @@ struct Buffer::Modification
     }
 };
 
-void Buffer::reload(BufferLines lines, time_t fs_timestamp)
+void Buffer::reload(BufferLines lines, timespec fs_timestamp)
 {
     if (lines.empty())
         lines.emplace_back(StringData::create("\n"));
@@ -531,13 +531,13 @@ ByteCoord Buffer::char_prev(ByteCoord coord) const
     return coord;
 }
 
-time_t Buffer::fs_timestamp() const
+timespec Buffer::fs_timestamp() const
 {
     kak_assert(m_flags & Flags::File);
     return m_fs_timestamp;
 }
 
-void Buffer::set_fs_timestamp(time_t ts)
+void Buffer::set_fs_timestamp(timespec ts)
 {
     kak_assert(m_flags & Flags::File);
     m_fs_timestamp = ts;
diff --git a/src/buffer.hh b/src/buffer.hh
index ba5a62df..5342dd83 100644
--- a/src/buffer.hh
+++ b/src/buffer.hh
@@ -14,7 +14,7 @@ namespace Kakoune
 
 class Buffer;
 
-constexpr time_t InvalidTime = 0;
+constexpr timespec InvalidTime = { -1, -1 };
 
 // A BufferIterator permits to iterate over the characters of a buffer
 class BufferIterator
@@ -79,7 +79,7 @@ public:
     };
 
     Buffer(String name, Flags flags, BufferLines lines = {},
-           time_t fs_timestamp = InvalidTime);
+           timespec fs_timestamp = InvalidTime);
     Buffer(const Buffer&) = delete;
     Buffer& operator= (const Buffer&) = delete;
     ~Buffer();
@@ -93,8 +93,8 @@ public:
     BufferIterator erase(BufferIterator begin, BufferIterator end);
 
     size_t         timestamp() const;
-    time_t         fs_timestamp() const;
-    void           set_fs_timestamp(time_t ts);
+    timespec       fs_timestamp() const;
+    void           set_fs_timestamp(timespec ts);
 
     void           commit_undo_group();
     bool           undo();
@@ -152,7 +152,7 @@ public:
 
     void run_hook_in_own_context(StringView hook_name, StringView param);
 
-    void reload(BufferLines lines, time_t fs_timestamp = InvalidTime);
+    void reload(BufferLines lines, timespec fs_timestamp = InvalidTime);
 
     void check_invariant() const;
 
@@ -213,7 +213,7 @@ private:
 
     Vector<Change, MemoryDomain::BufferMeta> m_changes;
 
-    time_t m_fs_timestamp;
+    timespec m_fs_timestamp;
 
     // Values are just data holding by the buffer, they are not part of its
     // observable state
diff --git a/src/buffer_utils.cc b/src/buffer_utils.cc
index c6795fe1..0bebf5d6 100644
--- a/src/buffer_utils.cc
+++ b/src/buffer_utils.cc
@@ -47,7 +47,7 @@ ByteCount get_byte_to_column(const Buffer& buffer, CharCount tabstop, CharCoord
 }
 
 Buffer* create_buffer_from_data(StringView data, StringView name,
-                                Buffer::Flags flags, time_t fs_timestamp)
+                                Buffer::Flags flags, timespec fs_timestamp)
 {
     bool bom = false, crlf = false;
 
@@ -98,7 +98,7 @@ Buffer* create_fifo_buffer(String name, int fd, bool scroll)
     if (buffer)
     {
         buffer->flags() |= Buffer::Flags::NoUndo;
-        buffer->reload({"\n"_ss}, 0);
+        buffer->reload({"\n"_ss}, InvalidTime);
     }
     else
         buffer = new Buffer(std::move(name), Buffer::Flags::Fifo | Buffer::Flags::NoUndo);
diff --git a/src/buffer_utils.hh b/src/buffer_utils.hh
index 33609150..ab02451f 100644
--- a/src/buffer_utils.hh
+++ b/src/buffer_utils.hh
@@ -34,7 +34,7 @@ Buffer* create_fifo_buffer(String name, int fd, bool scroll = false);
 
 Buffer* create_buffer_from_data(StringView data, StringView name,
                                 Buffer::Flags flags,
-                                time_t fs_timestamp = InvalidTime);
+                                timespec fs_timestamp = InvalidTime);
 
 void write_to_debug_buffer(StringView str);
 
diff --git a/src/client.cc b/src/client.cc
index 9da589b5..da218b7c 100644
--- a/src/client.cc
+++ b/src/client.cc
@@ -246,7 +246,7 @@ void Client::check_if_buffer_needs_reloading()
         return;
 
     const String& filename = buffer.name();
-    time_t ts = get_fs_timestamp(filename);
+    timespec ts = get_fs_timestamp(filename);
     if (ts == InvalidTime or ts == buffer.fs_timestamp())
         return;
     if (reload == Ask)
diff --git a/src/file.cc b/src/file.cc
index 2e67f872..ad526a93 100644
--- a/src/file.cc
+++ b/src/file.cc
@@ -180,13 +180,13 @@ Buffer* create_buffer_from_file(StringView filename)
         throw file_access_error(real_filename, "is a directory");
     if (S_ISFIFO(st.st_mode)) // Do not try to read fifos, use them as write only
         return create_buffer_from_data({}, real_filename,
-                                       Buffer::Flags::File, st.st_mtime);
+                                       Buffer::Flags::File, st.st_mtim);
 
     const char* data = (const char*)mmap(nullptr, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
     auto unmap = on_scope_end([&]{ munmap((void*)data, st.st_size); });
 
     return create_buffer_from_data({data, data + st.st_size}, real_filename,
-                                   Buffer::Flags::File, st.st_mtime);
+                                   Buffer::Flags::File, st.st_mtim);
 }
 
 static void write(int fd, StringView data)
@@ -423,11 +423,11 @@ Vector<String> complete_command(StringView prefix, ByteCount cursor_pos)
         return res;
     }
 
-    typedef decltype(stat::st_mtime) TimeSpec;
+    typedef decltype(stat::st_mtim) TimeSpec;
 
     struct CommandCache
     {
-        TimeSpec mtime = {};
+        TimeSpec mtim = {};
         Vector<String> commands;
     };
     static UnorderedMap<String, CommandCache, MemoryDomain::Commands> command_cache;
@@ -442,7 +442,7 @@ Vector<String> complete_command(StringView prefix, ByteCount cursor_pos)
             continue;
 
         auto& cache = command_cache[dirname];
-        if (memcmp(&cache.mtime, &st.st_mtime, sizeof(TimeSpec)) != 0)
+        if (memcmp(&cache.mtim, &st.st_mtim, sizeof(TimeSpec)) != 0)
         {
             auto filter = [&](const dirent& entry) {
                 struct stat st;
@@ -457,7 +457,7 @@ Vector<String> complete_command(StringView prefix, ByteCount cursor_pos)
             };
 
             cache.commands = list_files("", dirname, filter);
-            memcpy(&cache.mtime, &st.st_mtime, sizeof(TimeSpec));
+            memcpy(&cache.mtim, &st.st_mtim, sizeof(TimeSpec));
         }
         for (auto& cmd : cache.commands)
         {
@@ -471,12 +471,12 @@ Vector<String> complete_command(StringView prefix, ByteCount cursor_pos)
     return res;
 }
 
-time_t get_fs_timestamp(StringView filename)
+timespec get_fs_timestamp(StringView filename)
 {
     struct stat st;
     if (stat(filename.zstr(), &st) != 0)
         return InvalidTime;
-    return st.st_mtime;
+    return st.st_mtim;
 }
 
 String get_kak_binary_path()
diff --git a/src/file.hh b/src/file.hh
index ef51c2d8..6061d402 100644
--- a/src/file.hh
+++ b/src/file.hh
@@ -52,7 +52,17 @@ Vector<String> list_files(StringView directory);
 
 void make_directory(StringView dir);
 
-time_t get_fs_timestamp(StringView filename);
+timespec get_fs_timestamp(StringView filename);
+
+constexpr bool operator==(const timespec& lhs, const timespec& rhs)
+{
+    return lhs.tv_sec == rhs.tv_sec and lhs.tv_nsec == rhs.tv_nsec;
+}
+
+constexpr bool operator!=(const timespec& lhs, const timespec& rhs)
+{
+    return not (lhs == rhs);
+}
 
 CandidateList complete_filename(StringView prefix, const Regex& ignore_regex,
                                 ByteCount cursor_pos = -1);