[EditLine] Rewrite GetHistoryFilePath

Rewrite the GetHistoryFilePath implementation without relying on
FileSpec in the spirit of our discussion in D61994.

It changes LLDBs behavior in two ways:

1. We now only use the -widehistory suffix when LLDB is built with wchar
   support, instead of as the fallback from when the ~/.lldb directory
   isn't writable.

2. When the ~/.lldb directory isn't writable, we don't write any history
   files at all. Previously we would write them to the user's home
   directory (with the incorrect wide suffix), polluting ~ with a
   different file for every IO handler.

Differential revision: https://reviews.llvm.org/D62216

llvm-svn: 361412

1 files changed, 18 insertions, 13 deletions

diff --git a/lldb/source/Host/common/Editline.cpp b/lldb/source/Host/common/Editline.cpp
index aa52b4ca4f0..febb1e512ea 100644
--- a/lldb/source/Host/common/Editline.cpp
+++ b/lldb/source/Host/common/Editline.cpp
@@ -171,23 +171,28 @@ private:
   }
 
   const char *GetHistoryFilePath() {
+    // Compute the history path lazily.
     if (m_path.empty() && m_history && !m_prefix.empty()) {
-      FileSpec parent_path("~/.lldb");
-      FileSystem::Instance().Resolve(parent_path);
-      char history_path[PATH_MAX];
-      if (!llvm::sys::fs::create_directory(parent_path.GetPath())) {
-        snprintf(history_path, sizeof(history_path), "~/.lldb/%s-history",
-                 m_prefix.c_str());
-      } else {
-        snprintf(history_path, sizeof(history_path), "~/%s-widehistory",
-                 m_prefix.c_str());
+      llvm::SmallString<128> lldb_history_file;
+      llvm::sys::path::home_directory(lldb_history_file);
+      llvm::sys::path::append(lldb_history_file, ".lldb");
+
+      // LLDB stores its history in ~/.lldb/. If for some reason this directory
+      // isn't writable or cannot be created, history won't be available.
+      if (!llvm::sys::fs::create_directory(lldb_history_file)) {
+#if LLDB_EDITLINE_USE_WCHAR
+        std::string filename = m_prefix + "-widehistory";
+#else
+        std::string filename = m_prefix + "-history";
+#endif
+        llvm::sys::path::append(lldb_history_file, filename);
+        m_path = lldb_history_file.str();
       }
-      auto file_spec = FileSpec(history_path);
-      FileSystem::Instance().Resolve(file_spec);
-      m_path = file_spec.GetPath();
     }
+
     if (m_path.empty())
-      return NULL;
+      return nullptr;
+
     return m_path.c_str();
   }