[libclang/python] Expose Rewriter to the libclang python binding.

[jimmy-zx]

Exposes CXRewriter API to the python binding as in 69e5abb.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Jimmy Z (jimmy-zx)

Changes

Exposes CXRewriter API in 69e5abb.

---

Full diff: https://github.com/llvm/llvm-project/pull/71341.diff

2 Files Affected:

• (modified) clang/bindings/python/clang/cindex.py (+62)
• (added) clang/bindings/python/tests/cindex/test_rewrite.py (+74)

diff --git a/clang/bindings/python/clang/cindex.py b/clang/bindings/python/clang/cindex.py
index 6a16f3a9ef6e957..e51d558ab73fbce 100644
--- a/clang/bindings/python/clang/cindex.py
+++ b/clang/bindings/python/clang/cindex.py
@@ -3531,6 +3531,61 @@ def cursor(self):
         return cursor
 
 
+class Rewriter(ClangObject):
+    """
+    The Rewriter is a wrapper class around clang::Rewriter
+
+    It enables rewriting buffers.
+    """
+
+    @staticmethod
+    def create(tu):
+        """
+        Creates a new Rewriter
+        Parameters:
+        tu -- The translation unit for the target AST.
+        """
+        return Rewriter(conf.lib.clang_CXRewriter_create(tu))
+
+    def __init__(self, ptr):
+        ClangObject.__init__(self, ptr)
+
+    def __del__(self):
+        conf.lib.clang_CXRewriter_dispose(self)
+
+    def insertTextBefore(self, loc, insert):
+        """
+        Insert the specified string at the specified location in the original buffer.
+        """
+        conf.lib.clang_CXRewriter_insertTextBefore(self, loc, insert)
+
+    def replaceText(self, toBeReplaced, replacement):
+        """
+        This method replaces a range of characters in the input buffer with a new string.
+        """
+        conf.lib.clang_CXRewriter_replaceText(self, toBeReplaced, replacement)
+
+    def removeText(self, toBeRemoved):
+        """
+        Remove the specified text region.
+        """
+        conf.lib.clang_CXRewriter_removeText(self, toBeRemoved)
+
+    def overwriteChangedFiles(self):
+        """
+        Save all changed files to disk.
+        """
+        conf.lib.clang_CXRewriter_overwriteChangedFiles(self)
+
+    def writeMainFileToStdOut(self):
+        """
+        Writes the main file to stdout.
+        """
+        conf.lib.clang_CXRewriter_writeMainFileToStdOut(self)
+
+
+
+
 # Now comes the plumbing to hook up the C library.
 
 # Register callback types in common container.
@@ -3596,6 +3651,13 @@ def cursor(self):
     ("clang_codeCompleteGetNumDiagnostics", [CodeCompletionResults], c_int),
     ("clang_createIndex", [c_int, c_int], c_object_p),
     ("clang_createTranslationUnit", [Index, c_interop_string], c_object_p),
+    ("clang_CXRewriter_create", [TranslationUnit], c_object_p),
+    ("clang_CXRewriter_dispose", [Rewriter]),
+    ("clang_CXRewriter_insertTextBefore", [Rewriter, SourceLocation, c_interop_string]),
+    ("clang_CXRewriter_overwriteChangedFiles", [Rewriter], c_int),
+    ("clang_CXRewriter_removeText", [Rewriter, SourceRange]),
+    ("clang_CXRewriter_replaceText", [Rewriter, SourceRange, c_interop_string]),
+    ("clang_CXRewriter_writeMainFileToStdOut", [Rewriter]),
     ("clang_CXXConstructor_isConvertingConstructor", [Cursor], bool),
     ("clang_CXXConstructor_isCopyConstructor", [Cursor], bool),
     ("clang_CXXConstructor_isDefaultConstructor", [Cursor], bool),
diff --git a/clang/bindings/python/tests/cindex/test_rewrite.py b/clang/bindings/python/tests/cindex/test_rewrite.py
new file mode 100644
index 000000000000000..eb697f72a923030
--- /dev/null
+++ b/clang/bindings/python/tests/cindex/test_rewrite.py
@@ -0,0 +1,74 @@
+import sys
+import io
+import unittest
+import tempfile
+
+from clang.cindex import Rewriter, TranslationUnit, Config, File, SourceLocation, SourceRange
+
+class TestRewrite(unittest.TestCase):
+    code = '''
+int test1;
+
+void test2(void);
+
+int f(int c) {
+    return c;
+}
+'''
+
+    @classmethod
+    def setUpClass(cls):
+        Config.set_compatibility_check(False)
+
+    def setUp(self):
+        self.tmp = tempfile.NamedTemporaryFile(suffix='.cpp', buffering=0)
+        self.tmp.write(TestRewrite.code.encode('utf-8'))
+        self.tmp.flush()
+        self.tu = TranslationUnit.from_source(self.tmp.name)
+        self.rew = Rewriter.create(self.tu)
+        self.file = File.from_name(self.tu, self.tmp.name)
+
+    def tearDown(self):
+        self.tmp.close()
+
+
+    def test_insert(self):
+        snip = '#include <cstdio>\n'
+
+        beginning = SourceLocation.from_offset(self.tu, self.file, 0)
+        self.rew.insertTextBefore(beginning, snip)
+        self.rew.overwriteChangedFiles()
+
+        with open(self.tmp.name, 'r', encoding='utf-8') as f:
+            self.assertEqual(f.read(), snip + TestRewrite.code)
+
+
+    def test_replace(self):
+        pattern = 'test2'
+        replacement = 'func'
+
+        offset = TestRewrite.code.find(pattern)
+        pattern_range = SourceRange.from_locations(
+            SourceLocation.from_offset(self.tu, self.file, offset),
+            SourceLocation.from_offset(self.tu, self.file, offset + len(pattern))
+            )
+        self.rew.replaceText(pattern_range, replacement)
+        self.rew.overwriteChangedFiles()
+
+        with open(self.tmp.name, 'r', encoding='utf-8') as f:
+            self.assertEqual(f.read(), TestRewrite.code.replace(pattern, replacement))
+
+
+    def test_remove(self):
+        pattern = 'int c'
+
+        offset = TestRewrite.code.find(pattern)
+        pattern_range = SourceRange.from_locations(
+            SourceLocation.from_offset(self.tu, self.file, offset),
+            SourceLocation.from_offset(self.tu, self.file, offset + len(pattern))
+            )
+        self.rew.removeText(pattern_range)
+        self.rew.overwriteChangedFiles()
+
+        with open(self.tmp.name, 'r', encoding='utf-8') as f:
+            self.assertEqual(f.read(), TestRewrite.code.replace(pattern, ''))

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