In particular: this reads blocks from the input until it believes
that it's run out of input text. Each block is terminated by a
- double newline ('\n' followed by '\n'). As noted below, there is a
- bug in this code: it assumes that all the blocks have been read if
- it doesn't see additional text in the buffer after the last one is
- parsed, which will cause it to lose blocks if the last block
- coincides with the end of the buffer.
+ double newline ('\n' followed by '\n').
*/
bool ReadMessages(int Fd, vector<string> &List)
{
char Buffer[64000];
- char *End = Buffer;
// Represents any left-over from the previous iteration of the
// parse loop. (i.e., if a message is split across the end
// of the buffer, it goes here)
string PartialMessage;
-
- while (1)
- {
- int Res = read(Fd,End,sizeof(Buffer) - (End-Buffer));
+
+ do {
+ int const Res = read(Fd, Buffer, sizeof(Buffer));
if (Res < 0 && errno == EINTR)
continue;
-
- // Process is dead, this is kind of bad..
+
+ // process we read from has died
if (Res == 0)
return false;
-
+
// No data
- if (Res < 0 && errno == EAGAIN)
+ if (Res < 0 && (errno == EAGAIN || errno == EWOULDBLOCK))
return true;
if (Res < 0)
return false;
-
- End += Res;
-
- // Look for the end of the message
- for (char *I = Buffer; I + 1 < End; I++)
+
+ // extract the message(s) from the buffer
+ char const *Start = Buffer;
+ char const * const End = Buffer + Res;
+
+ char const * NL = (char const *) memchr(Start, '\n', End - Start);
+ if (NL == NULL)
{
- if (I[1] != '\n' ||
- (I[0] != '\n' && strncmp(I, "\r\n\r\n", 4) != 0))
- continue;
-
- // Pull the message out
- string Message(Buffer,I-Buffer);
- PartialMessage += Message;
-
- // Fix up the buffer
- for (; I < End && (*I == '\n' || *I == '\r'); ++I);
- End -= I-Buffer;
- memmove(Buffer,I,End-Buffer);
- I = Buffer;
-
- List.push_back(PartialMessage);
- PartialMessage.clear();
+ // end of buffer: store what we have so far and read new data in
+ PartialMessage.append(Start, End - Start);
+ Start = End;
}
- if (End != Buffer)
- {
- // If there's text left in the buffer, store it
- // in PartialMessage and throw the rest of the buffer
- // away. This allows us to handle messages that
- // are longer than the static buffer size.
- PartialMessage += string(Buffer, End);
- End = Buffer;
- }
else
- {
- // BUG ALERT: if a message block happens to end at a
- // multiple of 64000 characters, this will cause it to
- // terminate early, leading to a badly formed block and
- // probably crashing the method. However, this is the only
- // way we have to find the end of the message block. I have
- // an idea of how to fix this, but it will require changes
- // to the protocol (essentially to mark the beginning and
- // end of the block).
- //
- // -- dburrows 2008-04-02
- return true;
- }
+ ++NL;
+
+ if (PartialMessage.empty() == false && Start < End)
+ {
+ // if we start with a new line, see if the partial message we have ended with one
+ // so that we properly detect records ending between two read() runs
+ // cases are: \n|\n , \r\n|\r\n and \r\n\r|\n
+ // the case \r|\n\r\n is handled by the usual double-newline handling
+ if ((NL - Start) == 1 || ((NL - Start) == 2 && *Start == '\r'))
+ {
+ if (APT::String::Endswith(PartialMessage, "\n") || APT::String::Endswith(PartialMessage, "\r\n\r"))
+ {
+ PartialMessage.erase(PartialMessage.find_last_not_of("\r\n") + 1);
+ List.push_back(PartialMessage);
+ PartialMessage.clear();
+ while (NL < End && (*NL == '\n' || *NL == '\r')) ++NL;
+ Start = NL;
+ }
+ }
+ }
+
+ while (Start < End) {
+ char const * NL2 = (char const *) memchr(NL, '\n', End - NL);
+ if (NL2 == NULL)
+ {
+ // end of buffer: store what we have so far and read new data in
+ PartialMessage.append(Start, End - Start);
+ break;
+ }
+ ++NL2;
+
+ // did we find a double newline?
+ if ((NL2 - NL) == 1 || ((NL2 - NL) == 2 && *NL == '\r'))
+ {
+ PartialMessage.append(Start, NL2 - Start);
+ PartialMessage.erase(PartialMessage.find_last_not_of("\r\n") + 1);
+ List.push_back(PartialMessage);
+ PartialMessage.clear();
+ while (NL2 < End && (*NL2 == '\n' || *NL2 == '\r')) ++NL2;
+ Start = NL2;
+ }
+ NL = NL2;
+ }
+
+ // we have read at least one complete message and nothing left
+ if (PartialMessage.empty() == true)
+ return true;
if (WaitFd(Fd) == false)
return false;
- }
+ } while (true);
}
/*}}}*/
// MonthConv - Converts a month string into a number /*{{{*/
#include <config.h>
#include <apt-pkg/strutl.h>
+#include <apt-pkg/fileutl.h>
#include <string>
#include <vector>
#include <gtest/gtest.h>
+#include "file-helpers.h"
+
TEST(StrUtilTest,DeEscapeString)
{
// nothing special
EXPECT_EQ("Lg==", Base64Encode("."));
EXPECT_EQ("", Base64Encode(""));
}
+void ReadMessagesTestWithNewLine(char const * const nl, char const * const ab)
+{
+ SCOPED_TRACE(SubstVar(SubstVar(nl, "\n", "n"), "\r", "r") + " # " + ab);
+ FileFd fd;
+ std::string pkgA = "Package: pkgA\n"
+ "Version: 1\n"
+ "Size: 100\n"
+ "Description: aaa\n"
+ " aaa";
+ std::string pkgB = "Package: pkgB\n"
+ "Version: 1\n"
+ "Flag: no\n"
+ "Description: bbb";
+ std::string pkgC = "Package: pkgC\n"
+ "Version: 2\n"
+ "Flag: yes\n"
+ "Description:\n"
+ " ccc";
+
+ createTemporaryFile("readmessage", fd, NULL, (pkgA + nl + pkgB + nl + pkgC + nl).c_str());
+ std::vector<std::string> list;
+ EXPECT_TRUE(ReadMessages(fd.Fd(), list));
+ EXPECT_EQ(3, list.size());
+ EXPECT_EQ(pkgA, list[0]);
+ EXPECT_EQ(pkgB, list[1]);
+ EXPECT_EQ(pkgC, list[2]);
+
+ size_t const msgsize = 63990;
+ createTemporaryFile("readmessage", fd, NULL, NULL);
+ for (size_t j = 0; j < msgsize; ++j)
+ fd.Write(ab, strlen(ab));
+ for (size_t i = 0; i < 21; ++i)
+ {
+ std::string msg;
+ strprintf(msg, "msgsize=%zu i=%zu", msgsize, i);
+ SCOPED_TRACE(msg);
+ fd.Seek((msgsize + (i - 1)) * strlen(ab));
+ fd.Write(ab, strlen(ab));
+ fd.Write(nl, strlen(nl));
+ fd.Seek(0);
+ list.clear();
+ EXPECT_TRUE(ReadMessages(fd.Fd(), list));
+ EXPECT_EQ(1, list.size());
+ EXPECT_EQ((msgsize + i) * strlen(ab), list[0].length());
+ EXPECT_EQ(std::string::npos, list[0].find_first_not_of(ab));
+ }
+
+ list.clear();
+ fd.Write(pkgA.c_str(), pkgA.length());
+ fd.Write(nl, strlen(nl));
+ fd.Seek(0);
+ EXPECT_TRUE(ReadMessages(fd.Fd(), list));
+ EXPECT_EQ(2, list.size());
+ EXPECT_EQ((msgsize + 20) * strlen(ab), list[0].length());
+ EXPECT_EQ(std::string::npos, list[0].find_first_not_of(ab));
+ EXPECT_EQ(pkgA, list[1]);
+
+
+ fd.Close();
+}
+TEST(StrUtilTest,ReadMessages)
+{
+ ReadMessagesTestWithNewLine("\n\n", "a");
+ ReadMessagesTestWithNewLine("\r\n\r\n", "a");
+ ReadMessagesTestWithNewLine("\n\n", "ab");
+ ReadMessagesTestWithNewLine("\r\n\r\n", "ab");
+}
projects / apt.git / commitdiff
