Start pulling out pieces of the monolithic retain/release checker into

reusable and modular API pieces.

Start by pulling the logic for deriving the Cocoa naming convention
into a separate API, header, and source file.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@94662 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 129 insertions, 0 deletions

diff --git a/lib/Checker/CocoaConventions.cpp b/lib/Checker/CocoaConventions.cpp
new file mode 100644
index 0000000000..456b536d2d
--- /dev/null
+++ b/lib/Checker/CocoaConventions.cpp
@@ -0,0 +1,129 @@
+//===- CocoaConventions.h - Special handling of Cocoa conventions -*- C++ -*--//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines 
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Checker/DomainSpecific/CocoaConventions.h"
+#include "llvm/ADT/StringExtras.h"
+
+using namespace clang;
+
+using llvm::StringRef;
+
+// The "fundamental rule" for naming conventions of methods:
+//  (url broken into two lines)
+//  http://developer.apple.com/documentation/Cocoa/Conceptual/
+//     MemoryMgmt/Tasks/MemoryManagementRules.html
+//
+// "You take ownership of an object if you create it using a method whose name
+//  begins with "alloc" or "new" or contains "copy" (for example, alloc,
+//  newObject, or mutableCopy), or if you send it a retain message. You are
+//  responsible for relinquishing ownership of objects you own using release
+//  or autorelease. Any other time you receive an object, you must
+//  not release it."
+//
+
+static bool isWordEnd(char ch, char prev, char next) {
+  return ch == '\0'
+      || (islower(prev) && isupper(ch)) // xxxC
+      || (isupper(prev) && isupper(ch) && islower(next)) // XXCreate
+      || !isalpha(ch);
+}
+
+static const char* parseWord(const char* s) {
+  char ch = *s, prev = '\0';
+  assert(ch != '\0');
+  char next = *(s+1);
+  while (!isWordEnd(ch, prev, next)) {
+    prev = ch;
+    ch = next;
+    next = *((++s)+1);
+  }
+  return s;
+}
+
+cocoa::NamingConvention cocoa::deriveNamingConvention(Selector S) {
+  IdentifierInfo *II = S.getIdentifierInfoForSlot(0);
+
+  if (!II)
+    return NoConvention;
+
+  const char *s = II->getNameStart();
+
+  // A method/function name may contain a prefix.  We don't know it is there,
+  // however, until we encounter the first '_'.
+  bool InPossiblePrefix = true;
+  bool AtBeginning = true;
+  NamingConvention C = NoConvention;
+
+  while (*s != '\0') {
+    // Skip '_'.
+    if (*s == '_') {
+      if (InPossiblePrefix) {
+        // If we already have a convention, return it.  Otherwise, skip
+        // the prefix as if it wasn't there.
+        if (C != NoConvention)
+          break;
+        
+        InPossiblePrefix = false;
+        AtBeginning = true;
+        assert(C == NoConvention);
+      }
+      ++s;
+      continue;
+    }
+
+    // Skip numbers, ':', etc.
+    if (!isalpha(*s)) {
+      ++s;
+      continue;
+    }
+
+    const char *wordEnd = parseWord(s);
+    assert(wordEnd > s);
+    unsigned len = wordEnd - s;
+
+    switch (len) {
+    default:
+      break;
+    case 3:
+      // Methods starting with 'new' follow the create rule.
+      if (AtBeginning && StringRef(s, len).equals_lower("new"))
+        C = CreateRule;
+      break;
+    case 4:
+      // Methods starting with 'alloc' or contain 'copy' follow the
+      // create rule
+      if (C == NoConvention && StringRef(s, len).equals_lower("copy"))
+        C = CreateRule;
+      else // Methods starting with 'init' follow the init rule.
+        if (AtBeginning && StringRef(s, len).equals_lower("init"))
+          C = InitRule;
+      break;
+    case 5:
+      if (AtBeginning && StringRef(s, len).equals_lower("alloc"))
+        C = CreateRule;
+      break;
+    }
+
+    // If we aren't in the prefix and have a derived convention then just
+    // return it now.
+    if (!InPossiblePrefix && C != NoConvention)
+      return C;
+
+    AtBeginning = false;
+    s = wordEnd;
+  }
+
+  // We will get here if there wasn't more than one word
+  // after the prefix.
+  return C;
+}