Adds a sample TUI extension.

mychris · mychris · commit b2e07383820a · 2024-02-10T21:35:25.000+01:00
diff --git a/python/tree-tui/.gitignore b/python/tree-tui/.gitignore
@@ -0,0 +1 @@
+tree-tui
diff --git a/python/tree-tui/Makefile b/python/tree-tui/Makefile
@@ -0,0 +1,12 @@
+
+CC = clang
+
+all: tree-tui
+
+tree-tui: tree-tui.c
+	$(CC) -O0 -ggdb3 tree-tui.c -o tree-tui
+
+clean:
+	$(RM) tree-tui
+
+.PHONY: all clean
diff --git a/python/tree-tui/README.md b/python/tree-tui/README.md
@@ -0,0 +1,30 @@
+# tree-tui
+
+A sample extension which provides a TUI window that renders the first tree found
+in the current frame.
+
+## Usage
+
+Run gdb and either use the tree-tui.gdb file to load the extension, or do so manually.
+Breaking in main and stepping through it will show how the tree is build.  Breaking in
+`break_here` will show the full tree.
+
+A new TUI layout needs to be created like `tui new-layout tree tree 1 cmd 1`.
+Then, switch to the new layout with `layout tree`.  The tree-tui.gdb file
+will do that and sets breakpoints in `main` and `break_here`.
+
+Example output:
+
+```
+$ DEBUGINFOD_URLS= gdb -x ./tree-tui.gdb -ex run -ex continue ./tree-tui
+└── Root
+  ├── Child
+  │  ├── Grandchild
+  │  ├── Grandchild
+  │  ├── Grandchild
+  │  ├── Grandchild
+  │  ├── Grandchild
+  │  ├── Grandchild
+  │  └── Grandchild
+  ├── Child
+```
diff --git a/python/tree-tui/tree-tui.c b/python/tree-tui/tree-tui.c
@@ -0,0 +1,58 @@
+#include <stdlib.h>
+#include <string.h>
+
+struct Node {
+  char* name;
+  struct Node* childs[10];
+};
+
+typedef struct Node* Node;
+
+Node tree_create_child(struct Node* parent, const char* name)
+{
+  for (int i = 0; i < 10; ++i) {
+    if (NULL == parent->childs[i]) {
+      parent->childs[i] = calloc(1, sizeof(struct Node));
+      parent->childs[i]->name = strdup(name);
+      return parent->childs[i];
+    }
+  }
+  return NULL;
+}
+
+Node create_tree(const char* name)
+{
+  Node result = calloc(1, sizeof(struct Node));
+  result->name = strdup(name);
+  return result;
+}
+
+void tree_free(Node tree)
+{
+  free(tree->name);
+  for (int i = 0; i < 10; ++i) {
+    if (NULL != tree->childs[i]) {
+      tree_free(tree->childs[i]);
+    }
+  }
+  free(tree);
+}
+
+void break_here(Node tree)
+{
+  // Do nothing, set breakpoint here
+}
+
+int main(void)
+{
+  Node tree = create_tree("Root");
+  for (int i = 0; i < 5; ++i) {
+    Node child = tree_create_child(tree, "Child");
+    for (int j = 0; j < 7; ++j) {
+      tree_create_child(child, "Grandchild");
+    }
+  }
+  break_here(tree);
+  tree_free(tree);
+  return 0;
+}
diff --git a/python/tree-tui/tree-tui.gdb b/python/tree-tui/tree-tui.gdb
@@ -0,0 +1,7 @@
+
+source tree-tui.py
+tui new-layout tree tree 1 cmd 1
+tui new-layout tree-src tree 1 src 1 cmd 1
+layout tree
+break main
+break break_here
diff --git a/python/tree-tui/tree-tui.py b/python/tree-tui/tree-tui.py
@@ -0,0 +1,112 @@
+import gdb
+
+
+class TreeTui:
+    """A TUI window showing the first Node found on the stack"""
+    def __init__(self, window):
+        # The current TUI window
+        self.__window = window
+        self.__window.title = 'Tree View'
+        # The tree node found in __on_stop
+        self.__tree = None
+        # vertical position for scrolling
+        self.__vpos = 0
+        # horizontal position for scrolling
+        self.__hpos = 0
+        # content holding the whole tree as a string
+        self.__content = ''
+        # current line while rendering
+        self.__current_line = 0
+        # Create an event listener, which triggers rendering and
+        # discovers the tree
+        gdb.events.before_prompt.connect(self.__on_stop)
+
+    def __on_stop(self):
+        """Callback which searches for a Node object and renders the window"""
+        self.__tree = None
+        frame = gdb.selected_frame()
+        try:
+            block = frame.block()
+        except RuntimeError:
+            # Can happen if there are no debugging information
+            return
+        # Go through all the blocks until a Node is found
+        while not self.__tree and block:
+            # Go through this block and search for a Node
+            for x in block:
+                if not x.is_valid():
+                    continue
+                typ = x.type.strip_typedefs()
+                try:
+                    val = x.value(frame)
+                except Exception:
+                    continue
+                if typ.code == gdb.TYPE_CODE_PTR:
+                    if val and typ.target() == gdb.lookup_type("struct Node"):
+                        self.__tree = val.dereference()
+                        break
+            block = block.superblock
+        # Always render again!
+        self.render()
+
+    def close(self):
+        """Callback for window close event, disconnect the even listener"""
+        gdb.events.before_prompt.disconnect(self.__on_stop)
+
+    def vscroll(self, amount):
+        """Callback when the user scrolls vertically"""
+        self.__vpos = max(0, self.__vpos + amount)
+        # Always render again!
+        self.render()
+
+    def hscroll(self, amount):
+        """Callback when the user scrolls horizontally"""
+        self.__hpos = max(0, self.__hpos + amount)
+        # Always render again!
+        self.render()
+
+    def __render_line(self, content):
+        """Render a single line, handles scroll position and width/height"""
+        self.__current_line += 1
+        if self.__current_line > self.__window.height + self.__vpos:
+            return
+        if self.__current_line <= self.__vpos:
+            return
+        content = content[self.__hpos:]
+        content = content[:self.__window.width]
+        self.__content += content + '\n'
+
+    def __render(self, tree, last, header):
+        """Render the tree recursively"""
+        header_line = header
+        header_line += '└── ' if last else '├── '
+        try:
+            header_line += tree['name'].string()
+        except gdb.MemoryError:
+            return
+        self.__render_line(header_line)
+        try:
+            children = [tree['childs'][i] for i in range(10) if tree['childs'][i]]
+        except gdb.MemoryError:
+            children = []
+        for i in range(len(children)):
+            next_header = '   ' if last else '│  '
+            next_last = (i == len(children) - 1)
+            self.__render(tree['childs'][i], next_last, header + next_header)
+
+    def render(self):
+        """Render window callback"""
+        self.__content = ''
+        self.__current_line = 0
+        self.__window.erase()
+        if self.__tree:
+            self.__render(self.__tree, True, '')
+            self.__window.write(self.__content)
+        else:
+            self.__window.write('\n\n')
+            self.__window.write("No tree found".center(self.__window.width))
+            self.__window.write('\n')
+
+
+# Register the new TUI window
+gdb.register_window_type("tree", TreeTui)
