lldb/source/Utility/TildeExpressionResolver.cpp

   1 //===-- TildeExpressionResolver.cpp ---------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Utility/TildeExpressionResolver.h"
  10
  11 #include <cassert>
  12 #include <system_error>
  13
  14 #include "llvm/ADT/STLExtras.h"
  15 #include "llvm/ADT/SmallVector.h"
  16 #include "llvm/Support/FileSystem.h"
  17 #include "llvm/Support/Path.h"
  18 #include "llvm/Support/raw_ostream.h"
  19
  20 #if !defined(_WIN32)
  21 #include <pwd.h>
  22 #endif
  23
  24 using namespace lldb_private;
  25 using namespace llvm;
  26
  27 namespace fs = llvm::sys::fs;
  28 namespace path = llvm::sys::path;
  29
  30 TildeExpressionResolver::~TildeExpressionResolver() = default;
  31
  32 bool StandardTildeExpressionResolver::ResolveExact(
  33     StringRef Expr, SmallVectorImpl<char> &Output) {
  34   // We expect the tilde expression to be ONLY the expression itself, and
  35   // contain no separators.
  36   assert(!llvm::any_of(Expr, [](char c) { return path::is_separator(c); }));
  37   assert(Expr.empty() || Expr[0] == '~');
  38
  39   return !fs::real_path(Expr, Output, true);
  40 }
  41
  42 bool StandardTildeExpressionResolver::ResolvePartial(StringRef Expr,
  43                                                      StringSet<> &Output) {
  44   // We expect the tilde expression to be ONLY the expression itself, and
  45   // contain no separators.
  46   assert(!llvm::any_of(Expr, [](char c) { return path::is_separator(c); }));
  47   assert(Expr.empty() || Expr[0] == '~');
  48
  49   Output.clear();
  50 #if defined(_WIN32) || defined(__ANDROID__)
  51   return false;
  52 #else
  53   if (Expr.empty())
  54     return false;
  55
  56   SmallString<32> Buffer("~");
  57   setpwent();
  58   struct passwd *user_entry;
  59   Expr = Expr.drop_front();
  60
  61   while ((user_entry = getpwent()) != nullptr) {
  62     StringRef ThisName(user_entry->pw_name);
  63     if (!ThisName.startswith(Expr))
  64       continue;
  65
  66     Buffer.resize(1);
  67     Buffer.append(ThisName);
  68     Buffer.append(path::get_separator());
  69     Output.insert(Buffer);
  70   }
  71
  72   return true;
  73 #endif
  74 }
  75
  76 bool TildeExpressionResolver::ResolveFullPath(
  77     StringRef Expr, llvm::SmallVectorImpl<char> &Output) {
  78   if (!Expr.startswith("~")) {
  79     Output.assign(Expr.begin(), Expr.end());
  80     return false;
  81   }
  82
  83   namespace path = llvm::sys::path;
  84   StringRef Left =
  85       Expr.take_until([](char c) { return path::is_separator(c); });
  86
  87   if (!ResolveExact(Left, Output)) {
  88     Output.assign(Expr.begin(), Expr.end());
  89     return false;
  90   }
  91
  92   Output.append(Expr.begin() + Left.size(), Expr.end());
  93   return true;
  94 }