https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#nio_support
- We only store a ref to the following if JNI support for
+ We only store a ref to byteBuffer.klazz if JNI support for
ByteBuffer is available (which we determine during static init).
*/
- jclass cByteBuffer /* global ref to java.nio.ByteBuffer */;
- jmethodID byteBufferAlloc/* ByteBuffer.allocateDirect() */;
+ struct {
+ jclass klazz /* global ref to java.nio.ByteBuffer */;
+ jmethodID midAlloc /* ByteBuffer.allocateDirect() */;
+ jmethodID midLimit /* ByteBuffer.limit() */;
+ } byteBuffer;
} g;
/*
** The list of Java-side auto-extensions
if( jBytes ) (*env)->ReleaseByteArrayElements(env, jByteArray, jBytes, JNI_COMMIT)
/*
-** If jbb is-a java.nio.Buffer object and the JNI environment
-** supports it, *pBuf is set to the buffer's memory and *pN is set to
-** its length. If jbb is NULL, not a Buffer, or the JNI environment
-** does not support that operation, *pBuf is set to 0 and *pN is set
-** to 0.
+** If jbb is-a java.nio.Buffer object and the JNI environment supports
+** it, *pBuf is set to the buffer's memory and *pN is set to its
+** limit() (as opposed to its capacity()). If jbb is NULL, not a
+** Buffer, or the JNI environment does not support that operation,
+** *pBuf is set to 0 and *pN is set to 0.
**
** Note that the length of the buffer can be larger than SQLITE_LIMIT
** but this function does not know what byte range of the buffer is
** required so cannot check for that violation. The caller is required
** to ensure that any to-be-bind()ed range fits within SQLITE_LIMIT.
- */
+**
+** Sidebar: it is unfortunate that we cannot get ByteBuffer.limit()
+** via a JNI method like we can for ByteBuffer.capacity(). We instead
+** have to call back into Java to get the limit(). Depending on how
+** the ByteBuffer is used, the limit and capacity might be the same,
+** but when reusing a buffer, the limit may well change whereas the
+** capacity is fixed. The problem with, e.g., read()ing blob data to a
+** ByteBuffer's memory based on its capacity is that Java-level code
+** is restricted to accessing the range specified in
+** ByteBuffer.limit(). If we were to honor only the capacity, we
+** could end up writing to, or reading from, parts of a ByteBuffer
+** which client code itself cannot access without explicitly modifying
+** the limit. The penalty we pay for this correctness is that we must
+** call into Java to get the limit() of every ByteBuffer we work with.
+**
+** An alternative to having to call into ByteBuffer.limit() from here
+** would be to add private native impls of all ByteBuffer-using
+** methods, each of which adds a jint parameter which _must_ be set to
+** theBuffer.limit() by public Java APIs which use those private impls
+** to do the real work.
+*/
static void s3jni__get_nio_buffer(JNIEnv * const env, jobject jbb, void **pBuf, jint * pN ){
*pBuf = 0;
*pN = 0;
if( jbb ){
*pBuf = (*env)->GetDirectBufferAddress(env, jbb);
- *pN = *pBuf ? (jint)(*env)->GetDirectBufferCapacity(env, jbb) : 0
- /* why the Java limits the buffer length to int but the JNI API
- uses a jlong for the length is a mystery. */;
+ if( *pBuf ){
+ /*
+ ** Maintenance reminder: do not use
+ ** (*env)->GetDirectBufferCapacity(env,jbb), even though it
+ ** would be much faster, for reasons explained in this
+ ** function's comments.
+ */
+ *pN = (*env)->CallIntMethod(env, jbb, SJG.g.byteBuffer.midLimit);
+ S3JniExceptionIsFatal("Error calling ByteBuffer.limit() method.");
+ }
}
}
#define s3jni_get_nio_buffer(JOBJ,vpOut,jpOut) \
/*
** Creates a new ByteBuffer instance with a capacity of n. assert()s
-** that SJG.g.cByteBuffer is not 0 and n>0.
+** that SJG.g.byteBuffer.klazz is not 0 and n>0.
*/
static jobject s3jni__new_ByteBuffer(JNIEnv * const env, int n){
jobject rv = 0;
- assert( SJG.g.cByteBuffer );
- assert( SJG.g.byteBufferAlloc );
+ assert( SJG.g.byteBuffer.klazz );
+ assert( SJG.g.byteBuffer.midAlloc );
assert( n > 0 );
- rv = (*env)->CallStaticObjectMethod(env, SJG.g.cByteBuffer,
- SJG.g.byteBufferAlloc, (jint)n);
+ rv = (*env)->CallStaticObjectMethod(env, SJG.g.byteBuffer.klazz,
+ SJG.g.byteBuffer.midAlloc, (jint)n);
S3JniIfThrew {
S3JniExceptionReport;
S3JniExceptionClear;
const void * p, int n){
jobject rv = NULL;
assert( n >= 0 );
- if( 0==n || !SJG.g.cByteBuffer ){
+ if( 0==n || !SJG.g.byteBuffer.klazz ){
return NULL;
}
rv = s3jni__new_ByteBuffer(env, n);
** sqlite3_result_nio_buffer(), and similar methods which take a
** ByteBuffer object as either input or output. Populates pArgs and
** returns 0 on success, non-0 if the operation should fail. The
-** caller is required to check for SJG.g.cByteBuffer!=0 before calling
+** caller is required to check for SJG.g.byteBuffer.klazz!=0 before calling
** this and reporting it in a way appropriate for that routine. This
-** function may assert() that SJG.g.cByteBuffer is not 0.
+** function may assert() that SJG.g.byteBuffer.klazz is not 0.
**
** The (jBuffer, iOffset, iHowMany) arguments are the (ByteBuffer, offset,
** length) arguments to the bind/result method.
pArgs->jBuf = jBuffer;
pArgs->iOffset = iOffset;
pArgs->iHowMany = iHowMany;
- assert( SJG.g.cByteBuffer );
+ assert( SJG.g.byteBuffer.klazz );
if( pArgs->iOffset<0 ){
return SQLITE_ERROR
/* SQLITE_MISUSE or SQLITE_RANGE would fit better but we use
sqlite3_stmt * pStmt = PtrGet_sqlite3_stmt(jpStmt);
S3JniNioArgs args;
int rc;
- if( !pStmt || !SJG.g.cByteBuffer ) return SQLITE_MISUSE;
+ if( !pStmt || !SJG.g.byteBuffer.klazz ) return SQLITE_MISUSE;
rc = s3jni_setup_nio_args(env, &args, jBuffer, iOffset, iN);
if(rc){
return rc;
sqlite3_blob * const b = LongPtrGet_sqlite3_blob(jpBlob);
S3JniNioArgs args;
int rc;
- if( !b || !SJG.g.cByteBuffer || iHowMany<0 ){
+ if( !b || !SJG.g.byteBuffer.klazz || iHowMany<0 ){
return SQLITE_MISUSE;
}else if( iTgtOff<0 || iSrcOff<0 ){
return SQLITE_ERROR
sqlite3_blob * const b = LongPtrGet_sqlite3_blob(jpBlob);
S3JniNioArgs args;
int rc;
- if( !b || !SJG.g.cByteBuffer ){
+ if( !b || !SJG.g.byteBuffer.klazz ){
return SQLITE_MISUSE;
}else if( iTgtOff<0 || iSrcOff<0 ){
return SQLITE_ERROR
S3JniApi(sqlite3_jni_supports_nio(), jboolean,1jni_1supports_1nio)(
JniArgsEnvClass
){
- return SJG.g.cByteBuffer ? JNI_TRUE : JNI_FALSE;
+ return SJG.g.byteBuffer.klazz ? JNI_TRUE : JNI_FALSE;
}
S3JniNioArgs args;
if( !pCx ){
return;
- }else if( !SJG.g.cByteBuffer ){
+ }else if( !SJG.g.byteBuffer.klazz ){
sqlite3_result_error(
pCx, "This JVM does not support JNI access to ByteBuffers.", -1
);
unsigned char buf[16] = {0};
jobject bb = (*env)->NewDirectByteBuffer(env, buf, 16);
if( bb ){
- SJG.g.cByteBuffer = S3JniRefGlobal((*env)->GetObjectClass(env, bb));
- SJG.g.byteBufferAlloc = (*env)->GetStaticMethodID(
- env, SJG.g.cByteBuffer, "allocateDirect", "(I)Ljava/nio/ByteBuffer;"
+ SJG.g.byteBuffer.klazz = S3JniRefGlobal((*env)->GetObjectClass(env, bb));
+ SJG.g.byteBuffer.midAlloc = (*env)->GetStaticMethodID(
+ env, SJG.g.byteBuffer.klazz, "allocateDirect", "(I)Ljava/nio/ByteBuffer;"
);
S3JniExceptionIsFatal("Error getting ByteBuffer.allocateDirect() method.");
+ SJG.g.byteBuffer.midLimit = (*env)->GetMethodID(
+ env, SJG.g.byteBuffer.klazz, "limit", "()I"
+ );
+ S3JniExceptionIsFatal("Error getting ByteBuffer.limit() method.");
S3JniUnrefLocal(bb);
}else{
- SJG.g.cByteBuffer = 0;
- SJG.g.byteBufferAlloc = 0;
+ SJG.g.byteBuffer.klazz = 0;
+ SJG.g.byteBuffer.midAlloc = 0;
}
}
-C JNI:\sadd\ssqlite3_blob_read_nio_buffer()\sand\siron\sout\sthe\sblob/ByteBuffer\sinterface\ssomewhat.
-D 2023-11-14T04:59:57.233
+C JNI:\suse\sByteBuffer.limit()\sinstead\sof\sByteBuffer.capacity()\swhen\sfiguring\sout\swhere\sthe\slogical\send\sof\sa\sByteBuffer\sis,\sfor\sreasons\sexplained\sat\slength\sin\snew\scode\scomments.\sThis\sis\sunfortunately\sslower\sbut\sis\sthe\scorrect\sway\sto\sdo\sit.
+D 2023-11-14T05:33:44.492
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
F ext/jni/GNUmakefile f2f3a31923293659b95225e932a286af1f2287d75bf88ad6c0fd1b9d9cd020d4
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F ext/jni/src/c/sqlite3-jni.h 0ed09051f16f612680603a297fefa2c131c4a7e98e0b41cdd9ece08428b47d48
F ext/jni/src/org/sqlite/jni/annotation/NotNull.java 02091a8112e33389f1c160f506cd413168c8dfacbeda608a4946c6e3557b7d5a
F ext/jni/src/org/sqlite/jni/annotation/Nullable.java 0b1879852707f752512d4db9d7edd0d8db2f0c2612316ce1c832715e012ff6ba
F ext/jni/src/org/sqlite/jni/capi/AuthorizerCallback.java c045a5b47e02bb5f1af91973814a905f12048c428a3504fbc5266d1c1be3de5a
F ext/jni/src/org/sqlite/jni/capi/AutoExtensionCallback.java 74cc4998a73d6563542ecb90804a3c4f4e828cb4bd69e61226d1a51f4646e759
F ext/jni/src/org/sqlite/jni/capi/BusyHandlerCallback.java 7b8e19810c42b0ad21a04b5d8c804b32ee5905d137148703f16a75b612c380ca
-F ext/jni/src/org/sqlite/jni/capi/CApi.java a7c53a3226c6826ada00752a651a31e6cce3b8d741a02b2d45cb0d1e3dfc3a80
+F ext/jni/src/org/sqlite/jni/capi/CApi.java 7b2eae29f21db915bd358f3fab1eb9f1a4cbc8b2cc4c78aab7309cd69b71958a
F ext/jni/src/org/sqlite/jni/capi/CallbackProxy.java 57e2d275dcebe690b1fc1f3d34eb96879b2d7039bce30b563aee547bf45d8a8b
F ext/jni/src/org/sqlite/jni/capi/CollationCallback.java e29bcfc540fdd343e2f5cca4d27235113f2886acb13380686756d5cabdfd065a
F ext/jni/src/org/sqlite/jni/capi/CollationNeededCallback.java 5bfa226a8e7a92e804fd52d6e42b4c7b875fa7a94f8e2c330af8cc244a8920ab
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 46656b354311ec0a36832af1c4ccb3b6a244aa55cfb3681e25c3f42b13b387dd
-R 4e0b6f66f2c79b3b0f3d9c780b63f86e
+P 7df317b448a09ae77e2c68cc901fdb6d56a2246c1313f06bebd1f3e53f02c19b
+R dddfec0befd08ab210a022ab61f478a4
U stephan
-Z 5994994aa13f973034ef1e21e15b70de
+Z 49fb00c3c45f37f7c83250698ea520ef
# Remove this line to create a well-formed Fossil manifest.
projects / thirdparty / sqlite.git / commitdiff
