Fluid: restructuring and rejuvenation of the source code.

* Add classes for application and project
* Removed all globals from Fluid.h
* Extracting args and project history into their own classes
* Moving globals into Application class
* Initialize values inside headers for some classes.
* Undo functionality wrapped in a class inside Project.
* File reader and writer are now linked to a project.
* Avoid global project access
* Nodes (former Types) will be managed by a new Tree class.
* Removed static members (hidden globals) form Node/Fl_Type.
* Adding Tree iterator.
* Use nullptr instead of 0, NULL, or 0L
* Renamed Fl_..._Type to ..._Node, FL_OVERRIDE -> override
* Renaming ..._type to ...::prototype
* Splitting Widget Panel into multiple files.
* Moved callback code into widget panel file.
* Cleaning up Fluid_Image -> Image_asset
* Moving Fd_Snap_Action into new namespace fld::app::Snap_Action etc.
* Moved mergeback into proj folder.
* `enum ID` is now `enum class Type`.

1 files changed, 539 insertions, 0 deletions

diff --git a/fluid/proj/mergeback.cxx b/fluid/proj/mergeback.cxx
new file mode 100644
index 000000000..12f272638
--- /dev/null
+++ b/fluid/proj/mergeback.cxx
@@ -0,0 +1,539 @@
+//
+// MergeBack code for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 2023-2025 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please see the following page on how to report bugs and issues:
+//
+//     https://www.fltk.org/bugs.php
+//
+
+#if 0
+// Matt: disabled
+
+#include "proj/mergeback.h"
+
+#include "Fluid.h"
+#include "proj/undo.h"
+#include "io/Code_Writer.h"
+#include "nodes/Function_Node.h"
+#include "nodes/Widget_Node.h"
+
+#include <FL/Fl_Window.H>
+#include <FL/fl_ask.H>
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <zlib.h>
+
+extern void propagate_load(Fl_Group*, void*);
+extern void load_panel();
+extern void redraw_browser();
+
+// TODO: add application user setting to control mergeback
+//        [] new projects default to mergeback
+//        [] check mergeback when loading project
+//        [] check mergeback when app gets focus
+//          [] always apply if safe
+// TODO: command line option for mergeback
+//        -mb or --merge-back
+//        -mbs or --merge-back-if-safe
+// NOTE: automatic mergeback on timer when file changes if app focus doesn't work
+// NOTE: allow the user to edit comment blocks
+
+/**
+ Merge external changes in a source code file back into the current project.
+
+ This experimental function reads a source code file line by line. When it
+ encounters a special tag in a line, the crc32 stored in the tag is compared
+ to the crc32 that was calculated from the code lines since the previous tag.
+
+ If the crc's differ, the user has modified the source file externally, and the
+ given block differs from the block as it was generated by FLUID. Depending on
+ the block type, the user has modified the widget code (FD_TAG_GENERIC), which
+ can not be transferred back into the project.
+
+ Modifications to code blocks and callbacks (CODE, CALLBACK) can be merged back
+ into the project. Their corresponding Node is found using the unique
+ node id that is part of the tag. The block is only merged back if the crc's
+ from the project and from the edited block differ.
+
+ The caller must make sure that this code file was generated by the currently
+ loaded project.
+
+ The user is informed in detailed dialogs what the function discovered and
+ offered to merge or cancel if appropriate. Just in case this function is
+ destructive, "undo" restores the state before a MergeBack.
+
+ Callers can set different task. FD_MERGEBACK_ANALYSE checks if there are any
+ modifications in the code file and returns -1 if there was an error, or a
+ bit field where bit 0 is set if internal structures were modified, bit 1 if
+ code was changed, and bit 2 if modified blocks were found, but no Type node.
+ Bit 3 is set, if code was changed in the code file *and* the project.
+
+ FD_MERGEBACK_INTERACTIVE checks for changes and presents a status dialog box
+ to the user if there were conflicting changes or if a mergeback is possible,
+ presenting the user the option to merge or cancel. Returns 0 if the project
+ remains unchanged, and 1 if the user merged changes back. -1 is returned if an
+ invalid tag was found.
+
+ FD_MERGEBACK_APPLY merges all changes back into the project without any
+ interaction. Returns 0 if nothing changed, and 1 if it merged any changes back.
+
+ FD_MERGEBACK_APPLY_IF_SAFE merges changes back only if there are no conflicts.
+ Returns 0 if nothing changed, and 1 if it merged any changes back, and -1 if
+ there were conflicts.
+
+ \note this function is currently part of fld::io::Code_Writer to get easy access
+ to our crc32 code that also wrote the code file originally.
+
+ \param[in] s path and filename of the source code file
+ \param[in] task see above
+ \return -1 if an error was found in a tag
+ \return -2 if no code file was found
+ \return see above
+ */
+int merge_back(const std::string &s, const std::string &p, int task) {
+  if (Fluid.proj.write_mergeback_data) {
+    Fd_Mergeback mergeback;
+    return mergeback.merge_back(s, p, task);
+  } else {
+    // nothing to be done if the mergeback option is disabled in the project
+    return 0;
+  }
+}
+
+/** Allocate and initialize MergeBack class. */
+Fd_Mergeback::Fd_Mergeback() :
+  code(nullptr),
+  line_no(0),
+  tag_error(0),
+  num_changed_code(0),
+  num_changed_structure(0),
+  num_uid_not_found(0),
+  num_possible_override(0)
+{
+}
+
+/** Release allocated resources. */
+Fd_Mergeback::~Fd_Mergeback()
+{
+  if (code) ::fclose(code);
+}
+
+/** Remove the first two spaces at every line start.
+ \param[inout] s block of C code
+ */
+void Fd_Mergeback::unindent(char *s) {
+  char *d = s;
+  bool line_start = true;
+  while (*s) {
+    if (line_start) {
+      if (*s>0 && isspace(*s)) s++;
+      if (*s>0 && isspace(*s)) s++;
+      line_start = false;
+    }
+    if (*s=='\r') s++;
+    if (*s=='\n') line_start = true;
+    *d++ = *s++;
+  }
+  *d = 0;
+}
+
+/**
+ Read a block of text from the source file and remove the leading two spaces in every line.
+ \param[in] start start of the block within the file
+ \param[in] end end of text within the file
+ \return a string holding the text that was found in the file
+ */
+std::string Fd_Mergeback::read_and_unindent_block(long start, long end) {
+  long bsize = end-start;
+  long here = ::ftell(code);
+  ::fseek(code, start, SEEK_SET);
+  char *block = (char*)::malloc(bsize+1);
+  size_t n = ::fread(block, bsize, 1, code);
+  if (n!=1)
+    block[0] = 0; // read error
+  else
+    block[bsize] = 0;
+  unindent(block);
+  std::string str = block;
+  ::free(block);
+  ::fseek(code, here, SEEK_SET);
+  return str;
+}
+
+/** Tell user the results of our MergeBack analysis and pop up a dialog to give
+ the user a choice to merge or cancel.
+ \return 1 if the user wants to merge (choice dialog was shown)
+ \return 0 if there is nothing to merge (no dialog was shown)
+ \return -1 if the user wants to cancel or an error occurred or an issue was presented
+        (message or choice dialog was shown)
+ */
+int Fd_Mergeback::ask_user_to_merge(const std::string &code_filename, const std::string &proj_filename) {
+  if (tag_error) {
+    fl_message("Comparing\n  \"%s\"\nto\n  \"%s\"\n\n"
+               "MergeBack found an error in line %d while reading tags\n"
+               "from the source code. Merging code back is not possible.",
+               code_filename.c_str(), proj_filename.c_str(), line_no);
+    return -1;
+  }
+  if (!num_changed_code && !num_changed_structure) {
+    return 0;
+  }
+  if (num_changed_structure && !num_changed_code) {
+    fl_message("Comparing\n  \"%1$s\"\nto\n  \"%2$s\"\n\n"
+               "MergeBack found %3$d modifications in the project structure\n"
+               "of the source code. These kind of changes can no be\n"
+               "merged back and will be lost when the source code is\n"
+               "generated again from the open project.",
+               code_filename.c_str(), proj_filename.c_str(), num_changed_structure);
+    return -1;
+  }
+  std::string msg = "Comparing\n  \"%1$s\"\nto\n  \"%2$s\"\n\n"
+                  "MergeBack found %3$d modifications in the source code.";
+  if (num_possible_override)
+    msg += "\n\nWARNING: %6$d of these modified blocks appear to also have\n"
+    "changed in the project. Merging will override changes in\n"
+    "the project with changes from the source code file.";
+  if (num_uid_not_found)
+    msg += "\n\nWARNING: for %4$d of these modifications no Type node\n"
+    "can be found and these modification can't be merged back.";
+  if (!num_possible_override && !num_uid_not_found)
+    msg += "\nMerging these changes back appears to be safe.";
+
+  if (num_changed_structure)
+    msg += "\n\nWARNING: %5$d modifications were found in the project\n"
+    "structure. These kind of changes can no be merged back\n"
+    "and will be lost when the source code is generated again\n"
+    "from the open project.";
+
+  if (num_changed_code==num_uid_not_found) {
+    fl_message(msg.c_str(),
+               code_filename.c_str(), proj_filename.c_str(),
+               num_changed_code, num_uid_not_found,
+               num_changed_structure, num_possible_override);
+    return -1;
+  } else {
+    msg +=    "\n\nClick Cancel to abort the MergeBack operation.\n"
+    "Click Merge to merge all code changes back into\n"
+    "the open project.";
+    int c = fl_choice(msg.c_str(), "Cancel", "Merge", nullptr,
+                      code_filename.c_str(), proj_filename.c_str(),
+                      num_changed_code, num_uid_not_found,
+                      num_changed_structure, num_possible_override);
+    if (c==0) return -1;
+    return 1;
+  }
+}
+
+/** Analyse the block and its corresponding widget callback.
+ Return findings in num_changed_code, num_changed_code, and num_uid_not_found.
+ */
+void Fd_Mergeback::analyse_callback(unsigned long code_crc, unsigned long tag_crc, int uid) {
+  Node *tp = Node::find_by_uid(uid);
+  if (tp && tp->is_true_widget()) {
+    std::string cb = tp->callback(); cb += "\n";
+    unsigned long project_crc = fld::io::Code_Writer::block_crc(cb.c_str());
+    // check if the code and project crc are the same, so this modification was already applied
+    if (project_crc!=code_crc) {
+      num_changed_code++;
+      // check if the block change on the project side as well, so we may override changes
+      if (project_crc!=tag_crc) {
+        num_possible_override++;
+      }
+    }
+  } else {
+    num_uid_not_found++;
+    num_changed_code++;
+  }
+}
+
+/** Analyse the block and its corresponding Code Type.
+ Return findings in num_changed_code, num_changed_code, and num_uid_not_found.
+ */
+void Fd_Mergeback::analyse_code(unsigned long code_crc, unsigned long tag_crc, int uid) {
+  Node *tp = Node::find_by_uid(uid);
+  if (tp && tp->is_a(ID_Code)) {
+    std::string code = tp->name(); code += "\n";
+    unsigned long project_crc = fld::io::Code_Writer::block_crc(code.c_str());
+    // check if the code and project crc are the same, so this modification was already applied
+    if (project_crc!=code_crc) {
+      num_changed_code++;
+      // check if the block change on the project side as well, so we may override changes
+      if (project_crc!=tag_crc) {
+        num_possible_override++;
+      }
+    }
+  } else {
+    num_changed_code++;
+    num_uid_not_found++;
+  }
+}
+
+
+/** Analyse the code file and return findings in class member variables.
+
+ The code file must be open for reading already.
+
+ * tag_error is set if a tag was found, but could not be read
+ * line_no returns the line where an error occurred
+ * num_changed_code is set to the number of changed code blocks in the file.
+   Code changes can be merged back to the project.
+ * num_changed_structure is set to the number of structural changes.
+   Structural changes outside of code blocks can not be read back.
+ * num_uid_not_found number of blocks that were modified, but the corresponding
+   type or widget can not be found in the project
+ * num_possible_override number of blocks that were changed in the code file,
+   but also were changed in the project.
+
+ \return -1 if reading a tag failed, otherwise 0
+ */
+int Fd_Mergeback::analyse() {
+  // initialize local variables
+  unsigned long code_crc = 0;
+  bool line_start = true;
+  char line[1024];
+  // bail if the caller has not opened a file yet
+  if (!code) return 0;
+  // initialize member variables to return our findings
+  line_no = 0;
+  tag_error = 0;
+  num_changed_code = 0;
+  num_changed_structure = 0;
+  num_uid_not_found = 0;
+  num_possible_override = 0;
+  code_crc = 0;
+  // loop through all lines in the code file
+  ::fseek(code, 0, SEEK_SET);
+  for (;;) {
+    // get the next line until end of file
+    if (fgets(line, 1023, code)==0) break;
+    line_no++;
+    const char *tag = strstr(line, "//~fl~");
+    if (!tag) {
+      // if this line has no tag, add the contents to the CRC and continue
+      code_crc = fld::io::Code_Writer::block_crc(line, -1, code_crc, &line_start);
+    } else {
+      // if this line has a tag, read all tag data
+      int tag_type = -1, uid = 0;
+      unsigned long tag_crc = 0;
+      int n = sscanf(tag, "//~fl~%d~%04x~%08lx~~", &tag_type, &uid, &tag_crc);
+      if (n!=3 || tag_type<0 || tag_type>FD_TAG_LAST ) { tag_error = 1; return -1; }
+      if (code_crc != tag_crc) {
+        switch (tag_type) {
+          case FD_TAG_GENERIC:
+            num_changed_structure++;
+            break;
+          case FD_TAG_MENU_CALLBACK:
+          case FD_TAG_WIDGET_CALLBACK:
+            analyse_callback(code_crc, tag_crc, uid);
+            break;
+          case FD_TAG_CODE:
+            analyse_code(code_crc, tag_crc, uid);
+            break;
+        }
+      }
+      // reset everything for the next block
+      code_crc = 0;
+      line_start = true;
+    }
+  }
+  return 0;
+}
+
+/** Apply callback mergebacks from the code file to the project.
+ \return 1 if the project changed
+ */
+int Fd_Mergeback::apply_callback(long block_end, long block_start, unsigned long code_crc, int uid) {
+  Node *tp = Node::find_by_uid(uid);
+  if (tp && tp->is_true_widget()) {
+    std::string cb = tp->callback(); cb += "\n";
+    unsigned long project_crc = fld::io::Code_Writer::block_crc(cb.c_str());
+    if (project_crc!=code_crc) {
+      tp->callback(read_and_unindent_block(block_start, block_end).c_str());
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/** Apply callback mergebacks from the code file to the project.
+ \return 1 if the project changed
+ */
+int Fd_Mergeback::apply_code(long block_end, long block_start, unsigned long code_crc, int uid) {
+  Node *tp = Node::find_by_uid(uid);
+  if (tp && tp->is_a(ID_Code)) {
+    std::string cb = tp->name(); cb += "\n";
+    unsigned long project_crc = fld::io::Code_Writer::block_crc(cb.c_str());
+    if (project_crc!=code_crc) {
+      tp->name(read_and_unindent_block(block_start, block_end).c_str());
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/** Apply all possible mergebacks from the code file to the project.
+ The code file must be open for reading already.
+ \return -1 if reading a tag failed, 0 if nothing changed, 1 if the project changed
+ */
+int Fd_Mergeback::apply() {
+  // initialize local variables
+  unsigned long code_crc = 0;
+  bool line_start = true;
+  char line[1024];
+  int changed = 0;
+  long block_start = 0;
+  long block_end = 0;
+  // bail if the caller has not opened a file yet
+  if (!code) return 0;
+  // initialize member variables to return our findings
+  line_no = 0;
+  tag_error = 0;
+  code_crc = 0;
+  // loop through all lines in the code file
+  ::fseek(code, 0, SEEK_SET);
+  for (;;) {
+    // get the next line until end of file
+    if (fgets(line, 1023, code)==0) break;
+    line_no++;
+    const char *tag = strstr(line, "//~fl~");
+    if (!tag) {
+      // if this line has no tag, add the contents to the CRC and continue
+      code_crc = fld::io::Code_Writer::block_crc(line, -1, code_crc, &line_start);
+      block_end = ::ftell(code);
+    } else {
+      // if this line has a tag, read all tag data
+      int tag_type = -1, uid = 0;
+      unsigned long tag_crc = 0;
+      int n = sscanf(tag, "//~fl~%d~%04x~%08lx~~", &tag_type, &uid, &tag_crc);
+      if (n!=3 || tag_type<0 || tag_type>FD_TAG_LAST ) { tag_error = 1; return -1; }
+      if (code_crc != tag_crc) {
+        if (tag_type==FD_TAG_MENU_CALLBACK || tag_type==FD_TAG_WIDGET_CALLBACK) {
+          changed |= apply_callback(block_end, block_start, code_crc, uid);
+        } else if (tag_type==FD_TAG_CODE) {
+          changed |= apply_code(block_end, block_start, code_crc, uid);
+        }
+      }
+      // reset everything for the next block
+      code_crc = 0;
+      line_start = true;
+      block_start = ::ftell(code);
+    }
+  }
+  return changed;
+}
+
+/** Dispatch the MergeBack into analysis, interactive, or apply directly.
+ \param[in] s source code filename and path
+ \param[in] task one of FD_MERGEBACK_ANALYSE, FD_MERGEBACK_INTERACTIVE,
+            FD_MERGEBACK_APPLY_IF_SAFE, or FD_MERGEBACK_APPLY
+ \return -1 if an error was found in a tag
+ \return -2 if no code file was found
+ \return See more at ::merge_back(const std::string &s, int task).
+ */
+int Fd_Mergeback::merge_back(const std::string &s, const std::string &p, int task) {
+  int ret = 0;
+  code = fl_fopen(s.c_str(), "rb");
+  if (!code) return -2;
+  do { // no actual loop, just make sure we close the code file
+    if (task == FD_MERGEBACK_ANALYSE) {
+      analyse();
+      if (tag_error) {ret = -1; break; }
+      if (num_changed_structure) ret |= 1;
+      if (num_changed_code) ret |= 2;
+      if (num_uid_not_found) ret |= 4;
+      if (num_possible_override) ret |= 8;
+      break;
+    }
+    if (task == FD_MERGEBACK_INTERACTIVE) {
+      analyse();
+      ret = ask_user_to_merge(s, p);
+      if (ret != 1)
+        return ret;
+      task = FD_MERGEBACK_APPLY; // fall through
+    }
+    if (task == FD_MERGEBACK_APPLY_IF_SAFE) {
+      analyse();
+      if (tag_error || num_changed_structure || num_possible_override) {
+        ret = -1;
+        break;
+      }
+      if (num_changed_code==0) {
+        ret = 0;
+        break;
+      }
+      task = FD_MERGEBACK_APPLY; // fall through
+    }
+    if (task == FD_MERGEBACK_APPLY) {
+      ret = apply();
+      if (ret == 1) {
+        Fluid.proj.set_modflag(1);
+        redraw_browser();
+        load_panel();
+      }
+      ret = 1; // avoid message box in caller
+    }
+  } while (0);
+  fclose(code);
+  code = nullptr;
+  return ret;
+}
+
+#if 0
+// Matt: disabled
+/**
+ Merge the possibly modified content of code files back into the project.
+ */
+int mergeback_code_files()
+{
+  flush_text_widgets();
+  if (!filename) return 1;
+  if (!Fluid.proj.write_mergeback_data) {
+    fl_message("MergeBack is not enabled for this project.\n"
+               "Please enable MergeBack in the project settings\n"
+               "dialog and re-save the project file and the code.");
+    return 0;
+  }
+
+  std::string proj_filename = Fluid.proj.projectfile_path() + Fluid.proj.projectfile_name();
+  std::string code_filename;
+#if 1
+  if (!Fluid.batch_mode) {
+    Fl_Preferences build_records(Fl_Preferences::USER_L, "fltk.org", "fluid-build");
+    Fl_Preferences path(build_records, proj_filename.c_str());
+    int i, n = proj_filename.size();
+    for (i=0; i<n; i++) if (proj_filename[i]=='\\') proj_filename[i] = '/';
+    preferences_get(path, "code", code_filename, "");
+  }
+#endif
+  if (code_filename.empty())
+    code_filename = Fluid.proj.codefile_path() + Fluid.proj.codefile_name();
+  if (!Fluid.batch_mode) proj.enter_project_dir();
+  int c = merge_back(code_filename, proj_filename, FD_MERGEBACK_INTERACTIVE);
+  if (!Fluid.batch_mode) proj.leave_project_dir();
+
+  if (c==0) fl_message("Comparing\n  \"%s\"\nto\n  \"%s\"\n\n"
+                       "MergeBack found no external modifications\n"
+                       "in the source code.",
+                       code_filename.c_str(), proj_filename.c_str());
+  if (c==-2) fl_message("No corresponding source code file found.");
+  return c;
+}
+
+void mergeback_cb(Fl_Widget *, void *) {
+  mergeback_code_files();
+}
+#endif
+
+#endif
+