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-rw-r--r--src/libmdsserver/mds-message.c255
-rw-r--r--src/libmdsserver/mds-message.h9
2 files changed, 164 insertions, 100 deletions
diff --git a/src/libmdsserver/mds-message.c b/src/libmdsserver/mds-message.c
index b05b0cf..739244a 100644
--- a/src/libmdsserver/mds-message.c
+++ b/src/libmdsserver/mds-message.c
@@ -89,6 +89,62 @@ void mds_message_destroy(mds_message_t* restrict this)
/**
+ * Extend the header list's allocation
+ *
+ * @param this The message
+ * @param extent The number of additional entries
+ * @return Zero on success, -1 on error
+ */
+int mds_message_extend_headers(mds_message_t* restrict this, size_t extent)
+{
+ char** new_headers = this->headers;
+ if (xrealloc(new_headers, this->header_count + extent, char*))
+ return -1;
+ this->headers = new_headers;
+ return 0;
+}
+
+
+/**
+ * Extend the read buffer by way of doubling
+ *
+ * @param this The message
+ * @return Zero on success, -1 on error
+ */
+static int mds_message_extend_buffer(mds_message_t* restrict this)
+{
+ char* new_buf = this->buffer;
+ if (xrealloc(new_buf, this->buffer_size << 1, char))
+ return -1;
+ this->buffer = new_buf;
+ this->buffer_size <<= 1;
+ return 0;
+}
+
+
+/**
+ * Reset the header list and the payload
+ *
+ * @param this The message
+ */
+static void reset_message(mds_message_t* restrict this)
+{
+ if (this->headers != NULL)
+ {
+ size_t i;
+ xfree(this->headers, this->header_count);
+ this->headers = NULL;
+ }
+ this->header_count = 0;
+
+ free(this->payload);
+ this->payload = NULL;
+ this->payload_size = 0;
+ this->payload_ptr = 0;
+}
+
+
+/**
* Read the headers the message and determine, and store, its payload's length
*
* @param this The message
@@ -154,6 +210,68 @@ static void unbuffer_beginning(mds_message_t* restrict this, size_t length, int
/**
+ * Remove the header–payload delimiter from the buffer,
+ * get the payload's size and allocate the payload
+ *
+ * @param this The message
+ * @return The return value follows the rules of `mds_message_read`
+ */
+static int initialise_payload(mds_message_t* restrict this)
+{
+ /* Remove the \n (end of empty line) we found from the buffer. */
+ unbuffer_beginning(this, 1, 1);
+
+ /* Get the length of the payload. */
+ if (get_payload_length(this) < 0)
+ return -2; /* Malformated value, enters unrecoverable state. */
+
+ /* Allocate the payload buffer. */
+ if (this->payload_size > 0)
+ if (xmalloc(this->payload, this->payload_size, char))
+ return -1;
+
+ return 0;
+}
+
+
+/**
+ * Create a header from the buffer and store it
+ *
+ * @param this The message
+ * @param length The length of the header, including LF-termination
+ * @return The return value follows the rules of `mds_message_read`
+ */
+static int store_header(mds_message_t* restrict this, size_t length)
+{
+ char* header;
+
+ /* Allocate the header. */
+ if (xmalloc(header, length, char))
+ return -1;
+ /* Copy the header data into the allocated header, */
+ memcpy(header, this->buffer, length * sizeof(char));
+ /* and NUL-terminate it. */
+ header[length - 1] = '\0';
+
+ /* Remove the header data from the read buffer. */
+ unbuffer_beginning(this, length, 1);
+
+ /* Make sure the the header syntax is correct so that
+ the program does not need to care about it. */
+ if (validate_header(header, length))
+ {
+ free(header);
+ return -2;
+ }
+
+ /* Store the header in the header list. */
+ this->headers[this->header_count++] = header;
+
+ return 0;
+}
+
+
+/**
* Read the next message from a file descriptor
*
* @param this Memory slot in which to store the new message
@@ -169,24 +287,15 @@ static void unbuffer_beginning(mds_message_t* restrict this, size_t length, int
int mds_message_read(mds_message_t* restrict this, int fd)
{
size_t header_commit_buffer = 0;
+ int r;
+
+#define try(INSTRUCTION) if ((r = INSTRUCTION) < 0) return r
/* If we are at stage 2, we are done and it is time to start over.
- This is important because the function coul have been interrupted. */
+ This is important because the function could have been interrupted. */
if (this->stage == 2)
{
- if (this->headers != NULL)
- {
- size_t i;
- xfree(this->headers, this->header_count);
- this->headers = NULL;
- }
- this->header_count = 0;
-
- free(this->payload);
- this->payload = NULL;
- this->payload_size = 0;
- this->payload_ptr = 0;
-
+ reset_message(this);
this->stage = 0;
}
@@ -196,76 +305,36 @@ int mds_message_read(mds_message_t* restrict this, int fd)
size_t n;
ssize_t got;
char* p;
+ size_t length;
/* Stage 0: headers. */
- if (this->stage == 0)
- /* Read all headers that we have stored into the read buffer. */
- while ((p = memchr(this->buffer, '\n', this->buffer_ptr * sizeof(char))) != NULL)
+ /* Read all headers that we have stored into the read buffer. */
+ while ((this->stage == 0) &&
+ ((p = memchr(this->buffer, '\n', this->buffer_ptr * sizeof(char))) != NULL))
+ if ((length = (size_t)(p - this->buffer)))
{
- size_t len = (size_t)(p - this->buffer) + 1;
- char* header;
-
- /* We have found an empty line, i.e. the end of the headers. */
- if (len == 1)
- {
- /* Remove the \n (end of empty line) we found from the buffer. */
- unbuffer_beginning(this, 1, 1);
-
- /* Get the length of the payload. */
- if (get_payload_length(this) < 0)
- return -2; /* Malformated value, enters unrecoverable state. */
-
- /* Allocate the payload buffer. */
- if (this->payload_size > 0)
- if (xmalloc(this->payload, this->payload_size, char))
- return -1;
-
- /* Mark end of stage, next stage is getting the payload. */
- this->stage = 1;
-
- /* Stop searching for headers. */
- break;
- }
-
/* We have found a header. */
- /* One every eighth header found with this function call,
+ /* On every eighth header found with this function call,
we prepare the header list for eight more headers so
that it does not need to be reallocated again and again. */
if (header_commit_buffer == 0)
- {
- char** old_headers = this->headers;
- header_commit_buffer = 8;
- n = this->header_count + header_commit_buffer;
- if (xrealloc(this->headers, n, char*))
- {
- this->headers = old_headers;
- return -1;
- }
- }
-
- /* Allocate the header. */
- if (xmalloc(header, len, char))
- return -1;
- /* Copy the header data into the allocated header, */
- memcpy(header, this->buffer, len * sizeof(char));
- /* and NUL-terminate it. */
- header[len - 1] = '\0';
+ try (mds_message_extend_headers(this, header_commit_buffer = 8));
- /* Remove the header data from the read buffer. */
- unbuffer_beginning(this, len, 1);
+ /* Create and store header. */
+ try (store_header(this, length + 1));
+ header_commit_buffer -= 1;
+ }
+ else
+ {
+ /* We have found an empty line, i.e. the end of the headers. */
- /* Make sure the the header syntax is correct so that
- the program does not need to care about it. */
- if (validate_header(header, len))
- {
- free(header);
- return -2;
- }
+ /* Remove the header–payload delimiter from the buffer,
+ get the payload's size and allocate the payload. */
+ try (initialise_payload(this));
- /* Store the header in the heaer list. */
- this->headers[this->header_count++] = header;
- header_commit_buffer -= 1;
+ /* Mark end of stage, next stage is getting the payload. */
+ this->stage = 1;
}
/* Stage 1: payload. */
@@ -274,30 +343,19 @@ int mds_message_read(mds_message_t* restrict this, int fd)
this->stage = 2;
return 0;
}
- if ((this->stage == 1) && (this->payload_size > 0)) /* FIXME: next message fails if not LF-terminated. */
+ if ((this->stage == 1) && (this->payload_size > 0))
{
/* How much of the payload that has not yet been filled. */
size_t need = this->payload_size - this->payload_ptr;
- if (this->buffer_ptr <= need)
- /* If we have everything that we need, just copy it into the payload buffer. */
- memcpy(this->payload + this->payload_ptr, this->buffer, this->buffer_ptr * sizeof(char));
- else
- {
- /* Otherwise, copy what we have, and remove it from the the read buffer. */
- memcpy(this->payload + this->payload_ptr, this->buffer, need * sizeof(char));
- unbuffer_beginning(this, need, 0);
- }
+ /* How much we have of that what is needed. */
+ size_t move = min(this->payload_ptr, need);
+
+ /* Copy what we have, and remove it from the the read buffer. */
+ memcpy(this->payload + this->payload_ptr, this->buffer, move * sizeof(char));
+ unbuffer_beginning(this, move, 1);
/* Keep track of how much we have read. */
- this->payload_ptr += this->buffer_ptr;
- if (this->buffer_ptr <= need)
- /* Reset the read pointer as the read buffer is empty now. */
- this->buffer_ptr = 0;
- else
- /* But if we head left over data that is for the next message,
- just move the pointer back as much as we read. (Which is
- actually what we do even we did not have excess data.) */
- this->buffer_ptr -= need;
+ this->payload_ptr += move;
/* If we have filled the payload, make the end of this stage,
i.e. that the message is complete, and return with success. */
@@ -313,16 +371,11 @@ int mds_message_read(mds_message_t* restrict this, int fd)
/* Figure out how much space we have left in the read buffer. */
n = this->buffer_size - this->buffer_ptr;
- /* If we do not have too much left, grow the buffer, */
+ /* If we do not have too much left, */
if (n < 128)
{
- char* old_buffer = this->buffer;
- if (xrealloc(this->buffer, this->buffer_size <<= 1, char))
- {
- this->buffer = old_buffer;
- this->buffer_size >>= 1;
- return -1;
- }
+ /* grow the buffer, */
+ try (mds_message_extend_buffer(this));
/* and recalculate how much space we have left. */
n = this->buffer_size - this->buffer_ptr;
@@ -340,6 +393,8 @@ int mds_message_read(mds_message_t* restrict this, int fd)
return -1;
}
}
+
+#undef try
}
diff --git a/src/libmdsserver/mds-message.h b/src/libmdsserver/mds-message.h
index fc1df99..72e1735 100644
--- a/src/libmdsserver/mds-message.h
+++ b/src/libmdsserver/mds-message.h
@@ -108,6 +108,15 @@ void mds_message_zero_initialise(mds_message_t* restrict this);
void mds_message_destroy(mds_message_t* restrict this);
/**
+ * Extend the header list's allocation
+ *
+ * @param this The message
+ * @param extent The number of additional entries
+ * @return Zero on success, -1 on error
+ */
+int mds_message_extend_headers(mds_message_t* restrict this, size_t extent);
+
+/**
* Read the next message from a file descriptor
*
* @param this Memory slot in which to store the new message
generated by cgit v1.2.3-70-g09d2 (git 2.47.0) at 2024-11-28 03:43:04 +0000