Move manifest utils into separate lib, to reduce libxml2 deps.

Summary:
Previously were in support.  Since many many things depend on support,
were all forced to also depend on libxml2, which we only want in a few cases.
This puts all the libxml2 deps in a separate lib to be used only in a few
places.

Reviewers: ruiu, thakis, rnk

Subscribers: mgorny, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D35819

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309070 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 252 insertions, 0 deletions

diff --git a/lib/WindowsManifest/CMakeLists.txt b/lib/WindowsManifest/CMakeLists.txt
new file mode 100644
index 00000000000..0bf5f421c18
--- /dev/null
+++ b/lib/WindowsManifest/CMakeLists.txt
@@ -0,0 +1,18 @@
+set(system_libs)

+if( CMAKE_HOST_UNIX )

+  if( LLVM_LIBXML2_ENABLED )

+    set(system_libs ${system_libs} ${LIBXML2_LIBS})

+  endif()

+endif()

+

+add_llvm_library(LLVMWindowsManifest

+  WindowsManifestMerger.cpp

+

+  ADDITIONAL_HEADER_DIRS

+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/WindowsManifest

+  ${Backtrace_INCLUDE_DIRS}

+

+  LINK_LIBS ${system_libs}

+  )

+

+set_property(TARGET LLVMWindowsManifest PROPERTY LLVM_SYSTEM_LIBS "${system_libs}")

diff --git a/lib/WindowsManifest/LLVMBuild.txt b/lib/WindowsManifest/LLVMBuild.txt
new file mode 100644
index 00000000000..d5de0275b66
--- /dev/null
+++ b/lib/WindowsManifest/LLVMBuild.txt
@@ -0,0 +1,22 @@
+;===- ./lib/WindowsManifest/LLVMBuild.txt ----------------------*- Conf -*--===;

+;

+;                     The LLVM Compiler Infrastructure

+;

+; This file is distributed under the University of Illinois Open Source

+; License. See LICENSE.TXT for details.

+;

+;===------------------------------------------------------------------------===;

+;

+; This is an LLVMBuild description file for the components in this subdirectory.

+;

+; For more information on the LLVMBuild system, please see:

+;

+;   http://llvm.org/docs/LLVMBuild.html

+;

+;===------------------------------------------------------------------------===;

+

+[component_0]

+type = Library

+name = WindowsManifest

+parent = Libraries

+required_libraries = Support

diff --git a/lib/WindowsManifest/WindowsManifestMerger.cpp b/lib/WindowsManifest/WindowsManifestMerger.cpp
new file mode 100644
index 00000000000..0c9e7fda579
--- /dev/null
+++ b/lib/WindowsManifest/WindowsManifestMerger.cpp
@@ -0,0 +1,212 @@
+//===-- WindowsManifestMerger.cpp ------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+//
+// This file implements the .manifest merger class.
+//
+//===---------------------------------------------------------------------===//
+
+#include "llvm/WindowsManifest/WindowsManifestMerger.h"
+#include "llvm/Support/MemoryBuffer.h"
+
+#include <stdarg.h>
+
+#define TO_XML_CHAR(X) reinterpret_cast<const unsigned char *>(X)
+#define FROM_XML_CHAR(X) reinterpret_cast<const char *>(X)
+
+using namespace llvm;
+
+namespace llvm {
+
+char WindowsManifestError::ID = 0;
+
+WindowsManifestError::WindowsManifestError(const Twine &Msg) : Msg(Msg.str()) {}
+
+void WindowsManifestError::log(raw_ostream &OS) const { OS << Msg; }
+
+#if LLVM_LIBXML2_ENABLED
+static bool xmlStringsEqual(const unsigned char *A, const unsigned char *B) {
+  return strcmp(FROM_XML_CHAR(A), FROM_XML_CHAR(B)) == 0;
+}
+#endif
+
+bool isMergeableElement(const unsigned char *ElementName) {
+  for (StringRef S : {"application", "assembly", "assemblyIdentity",
+                      "compatibility", "noInherit", "requestedExecutionLevel",
+                      "requestedPrivileges", "security", "trustInfo"}) {
+    if (S == FROM_XML_CHAR(ElementName))
+      return true;
+  }
+  return false;
+}
+
+XMLNodeImpl getChildWithName(XMLNodeImpl Parent,
+                             const unsigned char *ElementName) {
+#if LLVM_LIBXML2_ENABLED
+  for (XMLNodeImpl Child = Parent->children; Child; Child = Child->next)
+    if (xmlStringsEqual(Child->name, ElementName)) {
+      return Child;
+    }
+#endif
+  return nullptr;
+}
+
+const unsigned char *getAttribute(XMLNodeImpl Node,
+                                  const unsigned char *AttributeName) {
+#if LLVM_LIBXML2_ENABLED
+  for (xmlAttrPtr Attribute = Node->properties; Attribute != nullptr;
+       Attribute = Attribute->next) {
+    if (xmlStringsEqual(Attribute->name, AttributeName))
+      return Attribute->children->content;
+  }
+#endif
+  return nullptr;
+}
+
+Error mergeAttributes(XMLNodeImpl OriginalNode, XMLNodeImpl AdditionalNode) {
+#if LLVM_LIBXML2_ENABLED
+  for (xmlAttrPtr Attribute = AdditionalNode->properties; Attribute != nullptr;
+       Attribute = Attribute->next) {
+    if (const unsigned char *OriginalValue =
+            getAttribute(OriginalNode, Attribute->name)) {
+      // Attributes of the same name must also have the same value.  Otherwise
+      // an error is thrown.
+      if (!xmlStringsEqual(OriginalValue, Attribute->children->content))
+        return make_error<WindowsManifestError>(
+            Twine("conflicting attributes for ") +
+            FROM_XML_CHAR(OriginalNode->name));
+    } else {
+      char *NameCopy = strdup(FROM_XML_CHAR(Attribute->name));
+      char *ContentCopy = strdup(FROM_XML_CHAR(Attribute->children->content));
+      xmlNewProp(OriginalNode, TO_XML_CHAR(NameCopy), TO_XML_CHAR(ContentCopy));
+    }
+  }
+#endif
+  return Error::success();
+}
+
+Error treeMerge(XMLNodeImpl OriginalRoot, XMLNodeImpl AdditionalRoot) {
+#if LLVM_LIBXML2_ENABLED
+  XMLNodeImpl AdditionalFirstChild = AdditionalRoot->children;
+  for (XMLNodeImpl Child = AdditionalFirstChild; Child; Child = Child->next) {
+    XMLNodeImpl OriginalChildWithName;
+    if (!isMergeableElement(Child->name) ||
+        !(OriginalChildWithName =
+              getChildWithName(OriginalRoot, Child->name))) {
+      XMLNodeImpl NewChild = xmlCopyNode(Child, 1);
+      if (!NewChild)
+        return make_error<WindowsManifestError>(Twine("error when copying ") +
+                                                FROM_XML_CHAR(Child->name));
+      if (NewChild->ns)
+        xmlFreeNs(NewChild->ns); // xmlCopyNode explicitly defines default
+                                 // namespace, undo this here.
+      if (!xmlAddChild(OriginalRoot, NewChild))
+        return make_error<WindowsManifestError>(Twine("could not merge ") +
+                                                FROM_XML_CHAR(NewChild->name));
+    } else if (auto E = treeMerge(OriginalChildWithName, Child)) {
+      return E;
+    }
+  }
+  if (auto E = mergeAttributes(OriginalRoot, AdditionalRoot))
+    return E;
+#endif
+  return Error::success();
+}
+
+void stripCommentsAndText(XMLNodeImpl Root) {
+#if LLVM_LIBXML2_ENABLED
+  xmlNode StoreNext;
+  for (XMLNodeImpl Child = Root->children; Child; Child = Child->next) {
+    if (!xmlStringsEqual(Child->name, TO_XML_CHAR("text")) &&
+        !xmlStringsEqual(Child->name, TO_XML_CHAR("comment"))) {
+      stripCommentsAndText(Child);
+    } else {
+      StoreNext.next = Child->next;
+      XMLNodeImpl Remove = Child;
+      Child = &StoreNext;
+      xmlUnlinkNode(Remove);
+      xmlFreeNode(Remove);
+    }
+  }
+#endif
+}
+
+WindowsManifestMerger::~WindowsManifestMerger() {
+#if LLVM_LIBXML2_ENABLED
+  for (auto &Doc : MergedDocs)
+    xmlFreeDoc(Doc);
+#endif
+}
+
+Error WindowsManifestMerger::merge(const MemoryBuffer &Manifest) {
+#if LLVM_LIBXML2_ENABLED
+  if (Manifest.getBufferSize() == 0)
+    return make_error<WindowsManifestError>(
+        "attempted to merge empty manifest");
+  xmlSetGenericErrorFunc((void *)this, WindowsManifestMerger::errorCallback);
+  XMLDocumentImpl ManifestXML =
+      xmlReadMemory(Manifest.getBufferStart(), Manifest.getBufferSize(),
+                    "manifest.xml", nullptr, XML_PARSE_NOBLANKS);
+  xmlSetGenericErrorFunc(nullptr, nullptr);
+  if (auto E = getParseError())
+    return E;
+  XMLNodeImpl AdditionalRoot = xmlDocGetRootElement(ManifestXML);
+  stripCommentsAndText(AdditionalRoot);
+  if (CombinedDoc == nullptr) {
+    CombinedDoc = ManifestXML;
+  } else {
+    XMLNodeImpl CombinedRoot = xmlDocGetRootElement(CombinedDoc);
+    if (xmlStringsEqual(CombinedRoot->name, AdditionalRoot->name) &&
+        isMergeableElement(AdditionalRoot->name)) {
+      if (auto E = treeMerge(CombinedRoot, AdditionalRoot)) {
+        return E;
+      }
+    } else {
+      XMLNodeImpl NewChild = xmlCopyNode(AdditionalRoot, 1);
+      if (!NewChild)
+        return make_error<WindowsManifestError>("could not copy manifest");
+      if (!xmlAddChild(CombinedRoot, NewChild))
+        return make_error<WindowsManifestError>("could not append manifest");
+    }
+  }
+  MergedDocs.push_back(ManifestXML);
+#endif
+  return Error::success();
+}
+
+std::unique_ptr<MemoryBuffer> WindowsManifestMerger::getMergedManifest() {
+#if LLVM_LIBXML2_ENABLED
+  unsigned char *XmlBuff;
+  int BufferSize = 0;
+  if (CombinedDoc) {
+    std::unique_ptr<xmlDoc> OutputDoc(xmlNewDoc((const unsigned char *)"1.0"));
+    xmlDocSetRootElement(OutputDoc.get(), xmlDocGetRootElement(CombinedDoc));
+    xmlKeepBlanksDefault(0);
+    xmlDocDumpFormatMemory(OutputDoc.get(), &XmlBuff, &BufferSize, 1);
+  }
+  if (BufferSize == 0)
+    return nullptr;
+  return MemoryBuffer::getMemBuffer(
+      StringRef(FROM_XML_CHAR(XmlBuff), (size_t)BufferSize));
+#else
+  return nullptr;
+#endif
+}
+
+void WindowsManifestMerger::errorCallback(void *Ctx, const char *Format, ...) {
+  auto *Merger = (WindowsManifestMerger *)Ctx;
+  Merger->ParseErrorOccurred = true;
+}
+
+Error WindowsManifestMerger::getParseError() {
+  if (!ParseErrorOccurred)
+    return Error::success();
+  return make_error<WindowsManifestError>("invalid xml document");
+}
+
+} // namespace llvm