sheet: Add extension API for transforming the current file

Author: richiejp

app/cli.c

@@ -24,6 +24,7 @@
 #ifdef ZSVSHEET_BUILD
 #include "sheet/sheet_internal.h"
 #include "sheet/handlers_internal.h"
+#include "sheet/transformation.h"
 #endif
 #include "sheet/procedure.h"
 #include "sheet/key-bindings.h"
@@ -399,6 +400,11 @@ static struct zsv_ext_callbacks *zsv_ext_callbacks_init(struct zsv_ext_callbacks
     e->ext_sheet_open_file = zsvsheet_open_file;
     e->ext_sheet_register_proc = zsvsheet_register_proc;
     e->ext_sheet_register_proc_key_binding = zsvsheet_register_proc_key_binding;
+    e->ext_sheet_push_transformation = zsvsheet_push_transformation;
+    e->ext_sheet_transformation_writer = zsvsheet_transformation_writer;
+    e->ext_sheet_transformation_parser = zsvsheet_transformation_parser;
+    e->ext_sheet_transformation_filename = zsvsheet_transformation_filename;
+    e->ext_sheet_transformation_user_context = zsvsheet_transformation_user_context;
 #endif
   }
   return e;

app/ext_example/my_extension.c

@@ -107,6 +107,45 @@ zsvsheet_status my_test_command_handler(zsvsheet_proc_context_t ctx) {
   }
   return zsvsheet_status_ok;
 }
+
+struct transformation_context {
+  size_t col_count;
+  size_t row_count;
+};
+
+// Similar to a regular ZSV row handler used in ext_parse_all
+void my_transformation_row_handler(void *ctx) {
+  zsvsheet_transformation trn = ctx;
+  struct transformation_context *priv = zsv_cb.ext_sheet_transformation_user_context(trn);
+  zsv_parser parser = zsv_cb.ext_sheet_transformation_parser(trn);
+  zsv_csv_writer writer = zsv_cb.ext_sheet_transformation_writer(trn);
+
+  size_t j = zsv_cb.cell_count(parser);
+  for (size_t i = 0; i < j; i++) {
+    struct zsv_cell c = zsv_cb.get_cell(parser, i);
+    zsv_writer_cell(writer, i == 0, c.str, c.len, c.quoted);
+  }
+
+  priv->col_count += j;
+
+  if (!priv->row_count)
+    zsv_writer_cell_s(writer, 0, (const unsigned char *)"Column count", 0);
+  else
+    zsv_writer_cell_zu(writer, 0, priv->col_count);
+
+  priv->row_count++;
+}
+
+zsvsheet_status my_transformation_command_handler(zsvsheet_proc_context_t ctx) {
+  struct transformation_context my_ctx = {
+    .col_count = 0,
+    .row_count = 0,
+  };
+
+  // TODO: This probably should happen in another worker thread and while that is happening the status should display
+  //       that some work is in progress. The extension author will maybe want to have control over the status message.
+  return zsv_cb.ext_sheet_push_transformation(ctx, &my_ctx, my_transformation_row_handler);
+}
 #endif
 
 /**
@@ -141,6 +180,11 @@ enum zsv_ext_status zsv_ext_init(struct zsv_ext_callbacks *cb, zsv_execution_con
   if (proc_id < 0)
     return zsv_ext_status_error;
   zsv_cb.ext_sheet_register_proc_key_binding('t', proc_id);
+
+  proc_id = zsv_cb.ext_sheet_register_proc("my-transformation", "my transformation", my_transformation_command_handler);
+  if (proc_id < 0)
+    return zsv_ext_status_error;
+  zsv_cb.ext_sheet_register_proc_key_binding('T', proc_id);
 #endif
   return zsv_ext_status_ok;
 }

app/sheet/handlers.c

@@ -126,3 +126,57 @@ struct zsv_opts zsvsheet_buffer_get_zsv_opts(zsvsheet_buffer_t h) {
   struct zsv_opts opts = {0};
   return opts;
 }
+
+enum zsvsheet_status zsvsheet_push_transformation(zsvsheet_proc_context_t ctx, void *user_context,
+                                                  void (*row_handler)(void *exec_ctx)) {
+  zsvsheet_buffer_t buff = zsvsheet_buffer_current(ctx);
+  const char *filename = zsvsheet_buffer_data_filename(buff);
+  enum zsvsheet_status stat = zsvsheet_status_error;
+
+  if (!filename)
+    filename = zsvsheet_buffer_filename(buff);
+
+  // TODO: custom_prop_handler is not passed to extensions?
+  struct zsvsheet_transformation_opts opts = {
+    .custom_prop_handler = NULL,
+    .input_filename = filename,
+  };
+  zsvsheet_transformation trn;
+  struct zsv_opts zopts = zsvsheet_buffer_get_zsv_opts(buff);
+
+  zopts.ctx = user_context;
+  zopts.row_handler = row_handler;
+  zopts.stream = fopen(filename, "rb");
+
+  if (!zopts.stream)
+    goto out;
+
+  opts.zsv_opts = zopts;
+
+  enum zsv_status zst = zsvsheet_transformation_new(opts, &trn);
+  if (zst != zsv_status_ok)
+    return stat;
+
+  zsv_parser parser = zsvsheet_transformation_parser(trn);
+
+  while ((zst = zsv_parse_more(parser)) == zsv_status_ok)
+    ;
+
+  switch (zst) {
+  case zsv_status_no_more_input:
+  case zsv_status_cancelled:
+    break;
+  default:
+    goto out;
+  }
+
+  zst = zsv_finish(parser);
+  if (zst != zsv_status_ok)
+    goto out;
+
+  stat = zsvsheet_open_file(ctx, zsvsheet_transformation_filename(trn), &zopts);
+
+out:
+  zsvsheet_transformation_delete(trn);
+  return stat;
+}

app/sheet/handlers_internal.h

@@ -98,4 +98,9 @@ zsvsheet_status zsvsheet_register_command(int ch, const char *long_name,
                                           zsvsheet_status (*subcommand_handler)(zsvsheet_subcommand_context_t),
                                           zsvsheet_status (*handler)(zsvsheet_context_t));
 
+/**
+ * Transform the current buffer's underlying file into a new one and open the new file in a buffer
+ */
+enum zsvsheet_status zsvsheet_push_transformation(zsvsheet_proc_context_t ctx, void *user_context,
+                                                  void (*row_handler)(void *exec_ctx));
 #endif

include/zsv/ext.h

@@ -12,6 +12,7 @@
 #include <stdio.h>
 #include "common.h"
 #include "ext/sheet.h"
+#include "utils/writer.h"
 
 /**
  * @file ext.h
@@ -235,6 +236,36 @@ struct zsv_ext_callbacks {
    * Get zsv_opts used to open the buffer's data file
    */
   struct zsv_opts (*ext_sheet_buffer_get_zsv_opts)(zsvsheet_buffer_t h);
+
+  /**
+   * Create a new buffer from the current one using a transformation
+   * and make the new buffer the current one
+   */
+  zsvsheet_status (*ext_sheet_push_transformation)(zsvsheet_proc_context_t ctx, void *user_context,
+                                                   void (*row_handler)(void *ctx));
+
+  /**
+   * Get the writer associated with a transformation.
+   *
+   * The transformation itself is passed as the context variable to the row handler
+   */
+  zsv_csv_writer (*ext_sheet_transformation_writer)(zsvsheet_transformation trn);
+
+  /**
+   * Get the user provided context from the context provided to a transformation row handler
+   */
+  void *(*ext_sheet_transformation_user_context)(zsvsheet_transformation trn);
+
+  /**
+   * Get the parser from the context provided to a transformation row handler
+   */
+  zsv_parser (*ext_sheet_transformation_parser)(zsvsheet_transformation trn);
+
+  /**
+   * Get the filename that the transformation writer outputs to from the context provided to a transformation row
+   * handler.
+   */
+  const char *(*ext_sheet_transformation_filename)(zsvsheet_transformation trn);
 };
 
 /** @} */

include/zsv/ext/sheet.h

@@ -21,4 +21,6 @@ typedef struct zsvsheet_subcommand_context *zsvsheet_subcommand_context_t;
 typedef void *zsvsheet_buffer_t;
 // int zsvsheet_ext_keypress(zsvsheet_proc_context_t);
 
+typedef struct zsvsheet_transformation *zsvsheet_transformation;
+
 #endif