python/arfile.cc: Rewrite extraction code and add ArArchive.extractall().

The extraction code now reads smaller parts and does not use FileFd
anymore, so we can raise OSError with errno and filename if an error
occurs.

Also add extractall() to ArArchive to make our interface more like
tarfile.TarFile's one.

1 files changed, 76 insertions, 21 deletions

diff --git a/python/arfile.cc b/python/arfile.cc
index 4eb651dd..8b4f9c5b 100644
--- a/python/arfile.cc
+++ b/python/arfile.cc
@@ -24,6 +24,13 @@
 #include "apt_instmodule.h"
 #include <apt-pkg/arfile.h>
 #include <apt-pkg/error.h>
+#include <apt-pkg/sptr.h>
+#include <utime.h>
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 
 PyObject *armember_get_name(PyObject *self, void *closure)
 {
@@ -180,6 +187,55 @@ PyObject *ararchive_extractdata(PyArArchiveObject *self, PyObject *args)
     return result;
 }
 
+// Helper class to close the FD automatically.
+class IntFD {
+    public:
+    int fd;
+    inline operator int() { return fd; };
+    inline IntFD(int fd): fd(fd) { };
+    inline ~IntFD() { close(fd); };
+};
+
+static PyObject *_extract(FileFd &Fd, const ARArchive::Member *member,
+                          const char *dir)
+{
+    if (!Fd.Seek(member->Start))
+        return HandleErrors();
+
+    string outfile_str = flCombine(dir,member->Name);
+    char *outfile = (char*)outfile_str.c_str();
+
+    // We are not using FileFd here, because we want to raise OSErrror with
+    // the correct errno and filename. IntFD's are closed automatically.
+    IntFD outfd(open(outfile, O_NDELAY|O_WRONLY|O_CREAT|O_TRUNC|O_APPEND,
+		             member->Mode));
+    if (outfd == -1)
+        return PyErr_SetFromErrnoWithFilename(PyExc_OSError, outfile);
+    if (fchmod(outfd, member->Mode) == -1)
+        return PyErr_SetFromErrnoWithFilename(PyExc_OSError, outfile);
+    if (fchown(outfd, member->UID, member->GID) != 0 && errno != EPERM)
+        return PyErr_SetFromErrnoWithFilename(PyExc_OSError, outfile);
+
+    // Read 4 KiB from the file, until all of the file is read. Deallocated
+    // automatically when the function returns.
+    SPtrArray<char> value = new char[4096];
+    unsigned long size = member->Size;
+    unsigned long read = 4096;
+    while (size > 0) {
+        if (size < read)
+            read = size;
+        if (!Fd.Read(value, read, true))
+            return HandleErrors();
+        if (write(outfd, value, read) != (signed)read)
+            return PyErr_SetFromErrnoWithFilename(PyExc_OSError, outfile);
+        size -= read;
+    }
+    utimbuf time = {member->MTime, member->MTime};
+    if (utime(outfile,&time) == -1)
+        return PyErr_SetFromErrnoWithFilename(PyExc_OSError, outfile);
+    Py_RETURN_TRUE;
+}
+
 static const char *ararchive_extract_doc =
     "extract(name: str[, target: str]) -> bool\n\n"
     "Extract the member given by name into the directory given by target.\n"
@@ -200,31 +256,28 @@ PyObject *ararchive_extract(PyArArchiveObject *self, PyObject *args)
         PyErr_Format(PyExc_LookupError,"No member named '%s'",name);
         return 0;
     }
+    return _extract(self->Fd, member, target);
+}
 
-    if (!self->Fd.Seek(member->Start))
-        return HandleErrors();
+static const char *ararchive_extractall_doc =
+    "extract([target: str]) -> bool\n\n"
+    "Extract all into the directory given by target.\n"
+    "If the extraction failed, an error is raised. Otherwise, the method\n"
+    "returns True if the owner could be set or False if the owner could not\n"
+    "be changed.";
 
-    // Open the target file
-    FileFd outfd(flCombine(target,name), FileFd::WriteAny, member->Mode);
-    if (_error->PendingError() == true)
-        return HandleErrors();
+static PyObject *ararchive_extractall(PyArArchiveObject *self, PyObject *args)
+{
+    char *target = "";
+    if (PyArg_ParseTuple(args, "|s:extractall", &target) == 0)
+        return 0;
 
-    // Temporary buffer. We should probably split this into smaller parts.
-    char* value = new char[member->Size];
+    const ARArchive::Member *member = self->Object->Members();
 
-    // Read into the buffer
-    if (!self->Fd.Read(value, member->Size, true)) {
-        delete[] value;
-        return HandleErrors();
-    }
-    if (!outfd.Write(value, member->Size)) {
-        delete[] value;
-        return HandleErrors();
-    }
-    if (fchown(outfd.Fd(), member->UID, member->GID) == -1) {
-        delete[] value;
-        Py_RETURN_FALSE;
-    }
+    do {
+        if (_extract(self->Fd, member, target) == 0)
+            return 0;
+    } while ((member = member->Next));
     Py_RETURN_TRUE;
 }
 
@@ -306,6 +359,8 @@ PyMethodDef ararchive_methods[] = {
      ararchive_extractdata_doc},
     {"extract",(PyCFunction)ararchive_extract,METH_VARARGS,
      ararchive_extract_doc},
+    {"extractall",(PyCFunction)ararchive_extractall,METH_VARARGS,
+     ararchive_extractall_doc},
     {"getmembers",(PyCFunction)ararchive_getmembers,METH_NOARGS,
      ararchive_getmembers_doc},
     {"getnames",(PyCFunction)ararchive_getnames,METH_NOARGS,