MPD
0.20.18
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Helper class for moving asynchronous (non-blocking) InputStream implementations to the I/O thread. More...
#include <AsyncInputStream.hxx>
Public Member Functions | |
AsyncInputStream (const char *_url, Mutex &_mutex, Cond &_cond, size_t _buffer_size, size_t _resume_at) | |
virtual | ~AsyncInputStream () |
void | Check () final |
Check for errors that may have occurred in the I/O thread. More... | |
bool | IsEOF () noexceptfinal |
Returns true if the stream has reached end-of-file. More... | |
void | Seek (offset_type new_offset) final |
Seeks to the specified position in the stream. More... | |
Tag * | ReadTag () final |
Reads the tag from the stream. More... | |
bool | IsAvailable () noexceptfinal |
Returns true if the next read operation will not block: either data is available, or end-of-stream has been reached, or an error has occurred. More... | |
size_t | Read (void *ptr, size_t read_size) final |
Reads data from the stream into the caller-supplied buffer. More... | |
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InputStream (const char *_uri, Mutex &_mutex, Cond &_cond) | |
virtual | ~InputStream () |
Close the input stream and free resources. More... | |
const char * | GetURI () const |
The absolute URI which was used to open this stream. More... | |
void | Lock () |
void | Unlock () |
virtual void | Update () |
Update the public attributes. More... | |
void | SetReady () |
bool | IsReady () const |
Return whether the stream is ready for reading and whether the other attributes in this struct are valid. More... | |
void | WaitReady () |
void | LockWaitReady () |
Wrapper for WaitReady() which locks and unlocks the mutex; the caller must not be holding it already. More... | |
gcc_pure bool | HasMimeType () const noexcept |
gcc_pure const char * | GetMimeType () const noexcept |
void | ClearMimeType () noexcept |
gcc_nonnull_all void | SetMimeType (const char *_mime) |
void | SetMimeType (std::string &&_mime) |
gcc_pure bool | KnownSize () const noexcept |
gcc_pure offset_type | GetSize () const noexcept |
void | AddOffset (offset_type delta) noexcept |
gcc_pure offset_type | GetOffset () const noexcept |
gcc_pure offset_type | GetRest () const noexcept |
gcc_pure bool | IsSeekable () const noexcept |
gcc_pure bool | CheapSeeking () const noexcept |
Determines whether seeking is cheap. More... | |
void | LockSeek (offset_type offset) |
Wrapper for Seek() which locks and unlocks the mutex; the caller must not be holding it already. More... | |
void | Rewind () |
Rewind to the beginning of the stream. More... | |
void | LockRewind () |
void | Skip (offset_type _offset) |
Skip input bytes. More... | |
void | LockSkip (offset_type _offset) |
gcc_pure bool | LockIsEOF () noexcept |
Wrapper for IsEOF() which locks and unlocks the mutex; the caller must not be holding it already. More... | |
gcc_malloc Tag * | LockReadTag () |
Wrapper for ReadTag() which locks and unlocks the mutex; the caller must not be holding it already. More... | |
gcc_nonnull_all size_t | LockRead (void *ptr, size_t size) |
Wrapper for Read() which locks and unlocks the mutex; the caller must not be holding it already. More... | |
gcc_nonnull_all void | ReadFull (void *ptr, size_t size) |
Reads the whole data from the stream into the caller-supplied buffer. More... | |
gcc_nonnull_all void | LockReadFull (void *ptr, size_t size) |
Wrapper for ReadFull() which locks and unlocks the mutex; the caller must not be holding it already. More... | |
Protected Member Functions | |
void | SetTag (Tag *_tag) noexcept |
Pass an tag from the I/O thread to the client thread. More... | |
void | ClearTag () noexcept |
void | Pause () noexcept |
bool | IsPaused () const noexcept |
void | SetClosed () noexcept |
Declare that the underlying stream was closed. More... | |
bool | IsBufferEmpty () const noexcept |
bool | IsBufferFull () const noexcept |
gcc_pure size_t | GetBufferSpace () const noexcept |
Determine how many bytes can be added to the buffer. More... | |
CircularBuffer< uint8_t >::Range | PrepareWriteBuffer () noexcept |
void | CommitWriteBuffer (size_t nbytes) noexcept |
void | AppendToBuffer (const void *data, size_t append_size) noexcept |
Append data to the buffer. More... | |
virtual void | DoResume ()=0 |
Implement code here that will resume the stream after it has been paused due to full input buffer. More... | |
virtual void | DoSeek (offset_type new_offset)=0 |
The actual Seek() implementation. More... | |
bool | IsSeekPending () const noexcept |
void | SeekDone () noexcept |
Call this after seeking has finished. More... | |
Protected Attributes | |
std::exception_ptr | postponed_exception |
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bool | ready |
indicates whether the stream is ready for reading and whether the other attributes in this struct are valid More... | |
bool | seekable |
if true, then the stream is fully seekable More... | |
offset_type | size |
the size of the resource, or UNKNOWN_SIZE if unknown More... | |
offset_type | offset |
the current offset within the stream More... | |
Additional Inherited Members | |
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typedef ::offset_type | offset_type |
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static gcc_nonnull_all InputStreamPtr | Open (const char *uri, Mutex &mutex, Cond &cond) |
Opens a new input stream. More... | |
static gcc_nonnull_all InputStreamPtr | OpenReady (const char *uri, Mutex &mutex, Cond &cond) |
Just like Open(), but waits for the stream to become ready. More... | |
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Mutex & | mutex |
A mutex that protects the mutable attributes of this object and its implementation. More... | |
Cond & | cond |
A cond that gets signalled when the state of this object changes from the I/O thread. More... | |
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static constexpr offset_type | UNKNOWN_SIZE = -1 |
Helper class for moving asynchronous (non-blocking) InputStream implementations to the I/O thread.
Data is being read into a ring buffer, and that buffer is then consumed by another thread using the regular InputStream API.
Definition at line 36 of file AsyncInputStream.hxx.
AsyncInputStream::AsyncInputStream | ( | const char * | _url, |
Mutex & | _mutex, | ||
Cond & | _cond, | ||
size_t | _buffer_size, | ||
size_t | _resume_at | ||
) |
_buffer | a buffer allocated with HugeAllocate(); the destructor will free it using HugeFree() |
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virtual |
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protectednoexcept |
Append data to the buffer.
The size must fit into the buffer; see GetBufferSpace().
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finalvirtual |
Check for errors that may have occurred in the I/O thread.
Throws std::runtime_error on error.
Reimplemented from InputStream.
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inlineprotectednoexcept |
Definition at line 97 of file AsyncInputStream.hxx.
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protectednoexcept |
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protectedpure virtual |
Implement code here that will resume the stream after it has been paused due to full input buffer.
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protectedpure virtual |
The actual Seek() implementation.
This virtual method will be called from within the I/O thread. When the operation is finished, call SeekDone() to notify the caller.
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inlineprotectednoexcept |
Determine how many bytes can be added to the buffer.
Definition at line 128 of file AsyncInputStream.hxx.
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finalvirtualnoexcept |
Returns true if the next read operation will not block: either data is available, or end-of-stream has been reached, or an error has occurred.
The caller must lock the mutex.
Reimplemented from InputStream.
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inlineprotectednoexcept |
Definition at line 116 of file AsyncInputStream.hxx.
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inlineprotectednoexcept |
Definition at line 120 of file AsyncInputStream.hxx.
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finalvirtualnoexcept |
Returns true if the stream has reached end-of-file.
The caller must lock the mutex.
Implements InputStream.
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inlineprotectednoexcept |
Definition at line 103 of file AsyncInputStream.hxx.
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inlineprotectednoexcept |
Definition at line 157 of file AsyncInputStream.hxx.
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protectednoexcept |
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inlineprotectednoexcept |
Definition at line 132 of file AsyncInputStream.hxx.
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finalvirtual |
Reads data from the stream into the caller-supplied buffer.
Returns 0 on error or eof (check with IsEOF()).
The caller must lock the mutex.
Throws std::runtime_error on error.
ptr | the buffer to read into |
size | the maximum number of bytes to read |
Implements InputStream.
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finalvirtual |
Reads the tag from the stream.
The caller must lock the mutex.
Reimplemented from InputStream.
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finalvirtual |
Seeks to the specified position in the stream.
This will most likely fail if the "seekable" flag is false.
The caller must lock the mutex.
Throws std::runtime_error on error.
offset | the relative offset |
Reimplemented from InputStream.
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protectednoexcept |
Call this after seeking has finished.
It will notify the client thread.
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inlineprotectednoexcept |
Declare that the underlying stream was closed.
We will continue feeding Read() calls from the buffer until it runs empty.
Definition at line 112 of file AsyncInputStream.hxx.
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protectednoexcept |
Pass an tag from the I/O thread to the client thread.
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protected |
Definition at line 69 of file AsyncInputStream.hxx.