shada: Add generator key to the header

For use in viminfo→shada converters, plugins that allow editing ShaDa files or
any other software which generates ShaDa files for whatever purpose.

2 files changed, 14 insertions, 9 deletions

diff --git a/runtime/doc/starting.txt b/runtime/doc/starting.txt
index dfb80b7f98..2078e9761b 100644
--- a/runtime/doc/starting.txt
+++ b/runtime/doc/starting.txt
@@ -1182,14 +1182,19 @@ exactly four MessagePack objects:
    entry type:
 
    Entry type (name)   Entry data ~
-   1 (Header)          Map containing data that describes the NeoVim instance 
-                       that written this ShaDa file.  It is ignored when 
-                       reading ShaDa files.  Contains the following data:
+   1 (Header)          Map containing data that describes the generator 
+                       instance that wrote this ShaDa file.  It is ignored 
+                       when reading ShaDa files.  Contains the following data:
                        Key        Data ~
-                       version    Binary, NeoVim version.
+                       generator  Binary, software used to generate ShaDa 
+                                  file. Is equal to "nvim" when ShaDa file was 
+                                  written by NeoVim.
+                       version    Binary, generator version.
                        encoding   Binary, effective 'encoding' value.
                        max_kbyte  Integer, effective |shada-s| limit value.
                        pid        Integer, instance process ID.
+                       *          It is allowed to have any number of 
+                                  additional keys with any data.
    2 (SearchPattern)   Map containing data describing last used search or 
                        substitute pattern.  Normally ShaDa file contains two 
                        such entries: one with "ss" key set to true (describes 
diff --git a/src/nvim/shada.c b/src/nvim/shada.c
index 76ae82e309..322f485f48 100644
--- a/src/nvim/shada.c
+++ b/src/nvim/shada.c
@@ -2418,9 +2418,11 @@ static ShaDaWriteResult shada_write(ShaDaWriteDef *const sd_writer,
     .timestamp = os_time(),
     .data = {
       .header = {
-        .size = 4,
-        .capacity = 4,
+        .size = 5,
+        .capacity = 5,
         .items = ((KeyValuePair[]) {
+          { STATIC_CSTR_AS_STRING("generator"),
+            STRING_OBJ(STATIC_CSTR_AS_STRING("nvim")) },
           { STATIC_CSTR_AS_STRING("version"),
             STRING_OBJ(cstr_as_string(longVersion)) },
           { STATIC_CSTR_AS_STRING("max_kbyte"),
@@ -2605,9 +2607,7 @@ static ShaDaWriteResult shada_write(ShaDaWriteDef *const sd_writer,
       continue;
     }
     const char *const fname = (char *) (fm.fmark.fnum == 0
-                                        ? (fm.fname == NULL
-                                           ? NULL
-                                           : fm.fname)
+                                        ? (fm.fname == NULL ? NULL : fm.fname)
                                         : buf->b_ffname);
     if (fname == NULL) {
       continue;