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v0.5.1
https://github.com/python/cpython
Revision 749afe81ec0a4b92ad6b89a67c82f2c04f79c5ac authored by CtrlZvi on 25 May 2018, 08:03:25 UTC, committed by Andrew Svetlov on 25 May 2018, 08:03:25 UTC
The proactor event loop has a race condition when reading with
pausing/resuming. `resume_reading()` unconditionally schedules the read
function to read from the current future. If `resume_reading()` was
called before the previously scheduled done callback fires, this results
in two attempts to get the data from the most recent read and an
assertion failure. This commit tracks whether or not `resume_reading`
needs to reschedule the callback to restart the loop, preventing a
second attempt to read the data..
(cherry picked from commit 4151061855b571bf8a7579daa7875b8e243057b9)

Co-authored-by: CtrlZvi <viz+github@flippedperspective.com>
1 parent 36f066a
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Tip revision: 749afe81ec0a4b92ad6b89a67c82f2c04f79c5ac authored by CtrlZvi on 25 May 2018, 08:03:25 UTC
[3.6] bpo-26819: Prevent proactor double read on resume (GH-6921) (#7110)
Tip revision: 749afe8
tokenizer.h
#ifndef Py_TOKENIZER_H
#define Py_TOKENIZER_H
#ifdef __cplusplus
extern "C" {
#endif

#include "object.h"

/* Tokenizer interface */

#include "token.h"      /* For token types */

#define MAXINDENT 100   /* Max indentation level */

enum decoding_state {
    STATE_INIT,
    STATE_RAW,
    STATE_NORMAL        /* have a codec associated with input */
};

/* Tokenizer state */
struct tok_state {
    /* Input state; buf <= cur <= inp <= end */
    /* NB an entire line is held in the buffer */
    char *buf;          /* Input buffer, or NULL; malloc'ed if fp != NULL */
    char *cur;          /* Next character in buffer */
    char *inp;          /* End of data in buffer */
    char *end;          /* End of input buffer if buf != NULL */
    char *start;        /* Start of current token if not NULL */
    int done;           /* E_OK normally, E_EOF at EOF, otherwise error code */
    /* NB If done != E_OK, cur must be == inp!!! */
    FILE *fp;           /* Rest of input; NULL if tokenizing a string */
    int tabsize;        /* Tab spacing */
    int indent;         /* Current indentation index */
    int indstack[MAXINDENT];            /* Stack of indents */
    int atbol;          /* Nonzero if at begin of new line */
    int pendin;         /* Pending indents (if > 0) or dedents (if < 0) */
    const char *prompt, *nextprompt;          /* For interactive prompting */
    int lineno;         /* Current line number */
    int level;          /* () [] {} Parentheses nesting level */
            /* Used to allow free continuations inside them */
    /* Stuff for checking on different tab sizes */
#ifndef PGEN
    /* pgen doesn't have access to Python codecs, it cannot decode the input
       filename. The bytes filename might be kept, but it is only used by
       indenterror() and it is not really needed: pgen only compiles one file
       (Grammar/Grammar). */
    PyObject *filename;
#endif
    int altwarning;     /* Issue warning if alternate tabs don't match */
    int alterror;       /* Issue error if alternate tabs don't match */
    int alttabsize;     /* Alternate tab spacing */
    int altindstack[MAXINDENT];         /* Stack of alternate indents */
    /* Stuff for PEP 0263 */
    enum decoding_state decoding_state;
    int decoding_erred;         /* whether erred in decoding  */
    int read_coding_spec;       /* whether 'coding:...' has been read  */
    char *encoding;         /* Source encoding. */
    int cont_line;          /* whether we are in a continuation line. */
    const char* line_start;     /* pointer to start of current line */
#ifndef PGEN
    PyObject *decoding_readline; /* open(...).readline */
    PyObject *decoding_buffer;
#endif
    const char* enc;        /* Encoding for the current str. */
    const char* str;
    const char* input; /* Tokenizer's newline translated copy of the string. */

    /* async/await related fields; can be removed in 3.7 when async and await
       become normal keywords. */
    int async_def;        /* =1 if tokens are inside an 'async def' body. */
    int async_def_indent; /* Indentation level of the outermost 'async def'. */
    int async_def_nl;     /* =1 if the outermost 'async def' had at least one
                             NEWLINE token after it. */
};

extern struct tok_state *PyTokenizer_FromString(const char *, int);
extern struct tok_state *PyTokenizer_FromUTF8(const char *, int);
extern struct tok_state *PyTokenizer_FromFile(FILE *, const char*,
                                              const char *, const char *);
extern void PyTokenizer_Free(struct tok_state *);
extern int PyTokenizer_Get(struct tok_state *, char **, char **);
extern char * PyTokenizer_RestoreEncoding(struct tok_state* tok,
                                          int len, int *offset);

#ifdef __cplusplus
}
#endif
#endif /* !Py_TOKENIZER_H */
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