Revise the design of the Path concept per peer review. Too many changes to

note individually but these essence of it is to not derive from
std::string, clarify the interface, and provide better documentation.
There is now also (untested) implementations for AIX, Darwin, and SunOS.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16078 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 281 insertions, 86 deletions

diff --git a/lib/System/Unix/Path.cpp b/lib/System/Unix/Path.cpp
index 9253f8c9f7..9d9dd99103 100644
--- a/lib/System/Unix/Path.cpp
+++ b/lib/System/Unix/Path.cpp
@@ -13,126 +13,321 @@
 
 //===----------------------------------------------------------------------===//
 //=== WARNING: Implementation here must contain only generic UNIX code that
-//===          is guaranteed to work on all UNIX variants.
+//===          is guaranteed to work on *all* UNIX variants.
 //===----------------------------------------------------------------------===//
 
 #include "Unix.h"
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <Config/config.h>
+
+namespace llvm {
+using namespace sys;
+
+Path::Path(std::string unverified_path) 
+  : path(unverified_path)
+{
+  if (unverified_path.empty())
+    return;
+  if (this->is_valid()) 
+    return;
+  // oops, not valid.
+  path.clear();
+  ThrowErrno(unverified_path + ": path is not valid");
+}
+
+Path
+Path::GetRootDirectory() {
+  Path result;
+  result.set_directory("/");
+  return result;
+}
+
+Path
+Path::GetTemporaryDirectory() {
+  char pathname[MAXPATHLEN];
+  strcpy(pathname,"/tmp/llvm_XXXXXX");
+  if (0 == mkdtemp(pathname))
+    ThrowErrno(std::string(pathname) + ": Can't create temporary directory");
+  Path result;
+  result.set_directory(pathname);
+  assert(result.is_valid() && "mkdtemp didn't create a valid pathname!");
+  return result;
+}
+
+Path 
+Path::GetSystemLibraryPath1() {
+  return Path("/lib/");
+}
+
+Path 
+Path::GetSystemLibraryPath2() {
+  return Path("/usr/lib/");
+}
+
+Path 
+Path::GetLLVMDefaultConfigDir() {
+  return Path("/etc/llvm/");
+}
+
+Path 
+Path::GetLLVMConfigDir() {
+  Path result;
+  if (result.set_directory(LLVM_ETCDIR))
+    return result;
+  return GetLLVMDefaultConfigDir();
+}
+
+Path
+Path::GetUserHomeDirectory() {
+  const char* home = getenv("HOME");
+  if (home) {
+    Path result;
+    if (result.set_directory(home))
+      return result;
+  }
+  return GetRootDirectory();
+}
 
 bool
-Path::is_file() const {
-  if (!empty() && ((*this)[length()-1] !=  '/'))
-    return true;
-  return false;
+Path::exists() const {
+  return 0 == access(path.c_str(), F_OK );
 }
 
 bool
-Path::is_directory() const {
-  if ((!empty()) && ((*this)[length()-1] ==  '/'))
-    return true;
-  return false;
+Path::readable() const {
+  return 0 == access(path.c_str(), F_OK | R_OK );
+}
+
+bool
+Path::writable() const {
+  return 0 == access(path.c_str(), F_OK | W_OK );
 }
 
-void
-Path::create( bool create_parents) {
-  if ( is_directory() ) {
-    if ( create_parents )
-      this->create_directories( );
-    this->create_directory( );
-  } else if ( is_file() ) {
-    if ( create_parents )
-      this->create_directories( );
-    this->create_file( );
+bool
+Path::executable() const {
+  return 0 == access(path.c_str(), R_OK | X_OK );
+}
+
+std::string 
+Path::getLast() const {
+  // Find the last slash
+  size_t pos = path.rfind('/');
+
+  // Handle the corner cases
+  if (pos == std::string::npos)
+    return path;
+
+  // If the last character is a slash
+  if (pos == path.length()-1) {
+    // Find the second to last slash
+    size_t pos2 = path.rfind('/', pos-1);
+    if (pos2 == std::string::npos)
+      return path.substr(0,pos);
+    else
+      return path.substr(pos2+1,pos-pos2-1);
   }
+  // Return everything after the last slash
+  return path.substr(pos+1);
 }
 
-void
-Path::remove() {
-  if ( is_directory() ) {
-    if ( exists() )
-      this->remove_directory( );
-  } else if ( is_file() )
-    if ( exists() ) 
-      this->remove_file( );
+bool
+Path::set_directory(const std::string& a_path) {
+  if (a_path.size() == 0)
+    return false;
+  Path save(*this);
+  path = a_path;
+  size_t last = a_path.size() -1;
+  if (last != 0 && a_path[last] != '/')
+    path += '/';
+  if (!is_valid()) {
+    path = save.path;
+    return false;
+  }
+  return true;
 }
 
 bool
-Path::exists() {
-  char pathname[MAXPATHLEN];
-  this->fill(pathname,MAXPATHLEN);
-  int lastchar = this->length() - 1 ; 
-  if (pathname[lastchar] == '/') 
-    pathname[lastchar] = 0;
-  return 0 == access(pathname, F_OK );
+Path::set_file(const std::string& a_path) {
+  if (a_path.size() == 0)
+    return false;
+  Path save(*this);
+  path = a_path;
+  size_t last = a_path.size() - 1;
+  while (last > 0 && a_path[last] == '/')
+    last--;
+  path.erase(last+1);
+  if (!is_valid()) {
+    path = save.path;
+    return false;
+  }
+  return true;
 }
 
-void
-Path::create_directory( ) {
-  char pathname[MAXPATHLEN];
-  this->fill(pathname,MAXPATHLEN);
-  int lastchar = this->length() - 1 ; 
-  if (pathname[lastchar] == '/') 
-    pathname[lastchar] = 0;
-  if (0 != mkdir(pathname, S_IRWXU | S_IRWXG))
-    ThrowErrno(pathname);
+bool
+Path::append_directory(const std::string& dir) {
+  if (is_file()) 
+    return false;
+  Path save(*this);
+  path += dir;
+  path += "/";
+  if (!is_valid()) {
+    path = save.path;
+    return false;
+  }
+  return true;
 }
 
-void
-Path::create_directories() {
-  char pathname[MAXPATHLEN];
-  this->fill(pathname,MAXPATHLEN);
-  int lastchar = this->length() - 1 ; 
-  if (pathname[lastchar] == '/') 
-    pathname[lastchar] = 0;
+bool
+Path::elide_directory() {
+  if (is_file()) 
+    return false;
+  size_t slashpos = path.rfind('/',path.size());
+  if (slashpos == 0 || slashpos == std::string::npos)
+    return false;
+  if (slashpos == path.size() - 1)
+    slashpos = path.rfind('/',slashpos-1);
+  if (slashpos == std::string::npos)
+    return false;
+  path.erase(slashpos);
+  return true;
+}
 
-  char * next = index(pathname,'/');
-  if ( pathname[0] == '/') 
-    next = index(&pathname[1],'/');
-  while ( next != 0 )
-  {
-    *next = 0;
-    if (0 != access(pathname, F_OK | R_OK))
-      if (0 != mkdir(pathname, S_IRWXU | S_IRWXG))
-        ThrowErrno(pathname);
-    char* save = next;
-    next = index(pathname,'/');
-    *save = '/';
+bool
+Path::append_file(const std::string& file) {
+  if (!is_directory()) 
+    return false;
+  Path save(*this);
+  path += file;
+  if (!is_valid()) {
+    path = save.path;
+    return false;
   }
+  return true;
 }
 
-void
-Path::remove_directory()
-{
+bool
+Path::elide_file() {
+  if (is_directory()) 
+    return false;
+  size_t slashpos = path.rfind('/',path.size());
+  if (slashpos == std::string::npos)
+    return false;
+  path.erase(slashpos+1);
+  return true;
+}
+
+bool
+Path::append_suffix(const std::string& suffix) {
+  if (is_directory()) 
+    return false;
+  Path save(*this);
+  path.append(".");
+  path.append(suffix);
+  if (!is_valid()) {
+    path = save.path;
+    return false;
+  }
+  return true;
+}
+
+bool 
+Path::elide_suffix() {
+  if (is_directory()) return false;
+  size_t dotpos = path.rfind('.',path.size());
+  size_t slashpos = path.rfind('/',path.size());
+  if (slashpos != std::string::npos && dotpos != std::string::npos &&
+      dotpos > slashpos) {
+    path.erase(dotpos, path.size()-dotpos);
+    return true;
+  }
+  return false;
+}
+
+
+bool
+Path::create_directory( bool create_parents) {
+  // Make sure we're dealing with a directory
+  if (!is_directory()) return false;
+
+  // Get a writeable copy of the path name
   char pathname[MAXPATHLEN];
-  this->fill(pathname,MAXPATHLEN);
-  int lastchar = this->length() - 1 ; 
+  path.copy(pathname,MAXPATHLEN);
+
+  // Null-terminate the last component
+  int lastchar = path.length() - 1 ; 
   if (pathname[lastchar] == '/') 
     pathname[lastchar] = 0;
-  if ( 0 != rmdir(pathname))
-    ThrowErrno(pathname);
+
+  // If we're supposed to create intermediate directories
+  if ( create_parents ) {
+    // Find the end of the initial name component
+    char * next = strchr(pathname,'/');
+    if ( pathname[0] == '/') 
+      next = strchr(&pathname[1],'/');
+
+    // Loop through the directory components until we're done 
+    while ( next != 0 ) {
+      *next = 0;
+      if (0 != access(pathname, F_OK | R_OK | W_OK))
+        if (0 != mkdir(pathname, S_IRWXU | S_IRWXG))
+          ThrowErrno(std::string(pathname) + ": Can't create directory");
+      char* save = next;
+      next = strchr(pathname,'/');
+      *save = '/';
+    }
+  } else if (0 != mkdir(pathname, S_IRWXU | S_IRWXG)) {
+    ThrowErrno(std::string(pathname) + ": Can't create directory");
+  } 
+  return true;
 }
 
-void
+bool
 Path::create_file() {
-  char pathname[MAXPATHLEN];
-  this->fill(pathname,MAXPATHLEN);
-  int lastchar = this->length() - 1 ; 
-  if (pathname[lastchar] == '/') 
-    pathname[lastchar] = 0;
-  if (0 != creat(pathname, S_IRUSR | S_IWUSR))
-    ThrowErrno(pathname);
+  // Make sure we're dealing with a file
+  if (!is_file()) return false; 
+
+  // Create the file
+  if (0 != creat(path.c_str(), S_IRUSR | S_IWUSR))
+    ThrowErrno(std::string(path.c_str()) + ": Can't create file");
+
+  return true;
+}
+
+bool
+Path::destroy_directory(bool remove_contents) {
+  // Make sure we're dealing with a directory
+  if (!is_directory()) return false;
+
+  // If it doesn't exist, we're done.
+  if (!exists()) return true;
+
+  if (remove_contents) {
+    // Recursively descend the directory to remove its content
+    std::string cmd("/bin/rm -rf ");
+    cmd += path;
+    system(cmd.c_str());
+  } else {
+    // Otherwise, try to just remove the one directory
+    char pathname[MAXPATHLEN];
+    path.copy(pathname,MAXPATHLEN);
+    int lastchar = path.length() - 1 ; 
+    if (pathname[lastchar] == '/') 
+      pathname[lastchar] = 0;
+    if ( 0 != rmdir(pathname))
+      ThrowErrno(std::string(pathname) + ": Can't destroy directory");
+  }
+  return true;
+}
+
+bool
+Path::destroy_file() {
+  if (!is_file()) return false;
+  if (0 != unlink(path.c_str()))
+    ThrowErrno(std::string(path.c_str()) + ": Can't destroy file");
+  return true;
 }
 
-void
-Path::remove_file() {
-  char pathname[MAXPATHLEN];
-  this->fill(pathname,MAXPATHLEN);
-  int lastchar = this->length() - 1 ; 
-  if (pathname[lastchar] == '/') 
-    pathname[lastchar] = 0;
-  if (0 != unlink(pathname))
-    ThrowErrno(pathname);
 }
 
 // vim: sw=2