[pacman-dev] [PATCH] Add a fetch callback to allow front-end download support

Sebastian Nowicki sebnow at gmail.com
Fri Feb 20 02:31:07 EST 2009


This allows a frontend to define its own download algorithm so that the
libfetch dependency can be omitted without using an external process.  The
callback will be used if it is defined, otherwise the internal method
(libfetch) is used, if available.

The external download method was moved to pacman and is set as the fetch
callback, if the command is defined in the configuration file. As a result,
alpm_option_get_xfercommand() and alpm_option_set_xfercommand() have been
removed.

Signed-off-by: Sebastian Nowicki <sebnow at gmail.com>
---
 lib/libalpm/alpm.h   |   17 +++++++-
 lib/libalpm/dload.c  |  101 +------------------------------------------------
 lib/libalpm/handle.c |   33 +++++++++-------
 lib/libalpm/handle.h |    2 +-
 src/pacman/conf.h    |    6 +++
 src/pacman/pacman.c  |   96 +++++++++++++++++++++++++++++++++++++++++++++++-
 6 files changed, 137 insertions(+), 118 deletions(-)

diff --git a/lib/libalpm/alpm.h b/lib/libalpm/alpm.h
index 7b7ca4e..f444e93 100644
--- a/lib/libalpm/alpm.h
+++ b/lib/libalpm/alpm.h
@@ -83,6 +83,17 @@ int alpm_logaction(char *fmt, ...);
 typedef void (*alpm_cb_download)(const char *filename,
 		off_t xfered, off_t total);
 typedef void (*alpm_cb_totaldl)(off_t total);
+/** A callback for downloading files
+ * @param url the URL of the file to be downloaded
+ * @param localpath the directory to which the file should be downloaded
+ * @param mtimeold the modification time of the file previously downloaded
+ * @param mtimenew the modification time of the newly downloaded file.
+ * This should be set by the callback.
+ * @return 0 on success, 1 if the modification times are identical, -1 on
+ * error.
+ */
+typedef int (*alpm_cb_fetch)(const char *url, const char *localpath,
+		time_t mtimeold, time_t *mtimenew);
 
 /*
  * Options
@@ -94,6 +105,9 @@ void alpm_option_set_logcb(alpm_cb_log cb);
 alpm_cb_download alpm_option_get_dlcb();
 void alpm_option_set_dlcb(alpm_cb_download cb);
 
+alpm_cb_fetch alpm_option_get_fetchcb();
+void alpm_option_set_fetchcb(alpm_cb_fetch cb);
+
 alpm_cb_totaldl alpm_option_get_totaldlcb();
 void alpm_option_set_totaldlcb(alpm_cb_totaldl cb);
 
@@ -137,9 +151,6 @@ void alpm_option_add_ignoregrp(const char *grp);
 void alpm_option_set_ignoregrps(alpm_list_t *ignoregrps);
 int alpm_option_remove_ignoregrp(const char *grp);
 
-const char *alpm_option_get_xfercommand();
-void alpm_option_set_xfercommand(const char *cmd);
-
 unsigned short alpm_option_get_nopassiveftp();
 void alpm_option_set_nopassiveftp(unsigned short nopasv);
 void alpm_option_set_usedelta(unsigned short usedelta);
diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index 5b0a691..bc36706 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -262,111 +262,16 @@ cleanup:
 }
 #endif
 
-static int download_external(const char *url, const char *localpath,
-		time_t mtimeold, time_t *mtimenew) {
-	int ret = 0;
-	int retval;
-	int usepart = 0;
-	char *ptr1, *ptr2;
-	char origCmd[PATH_MAX];
-	char parsedCmd[PATH_MAX] = "";
-	char cwd[PATH_MAX];
-	char *destfile, *tempfile, *filename;
-
-	if(!handle->xfercommand) {
-		RET_ERR(PM_ERR_EXTERNAL_DOWNLOAD, -1);
-	}
-
-	filename = get_filename(url);
-	if(!filename) {
-		RET_ERR(PM_ERR_EXTERNAL_DOWNLOAD, -1);
-	}
-	destfile = get_destfile(localpath, filename);
-	tempfile = get_tempfile(localpath, filename);
-
-	/* replace all occurrences of %o with fn.part */
-	strncpy(origCmd, handle->xfercommand, sizeof(origCmd));
-	ptr1 = origCmd;
-	while((ptr2 = strstr(ptr1, "%o"))) {
-		usepart = 1;
-		ptr2[0] = '\0';
-		strcat(parsedCmd, ptr1);
-		strcat(parsedCmd, tempfile);
-		ptr1 = ptr2 + 2;
-	}
-	strcat(parsedCmd, ptr1);
-	/* replace all occurrences of %u with the download URL */
-	strncpy(origCmd, parsedCmd, sizeof(origCmd));
-	parsedCmd[0] = '\0';
-	ptr1 = origCmd;
-	while((ptr2 = strstr(ptr1, "%u"))) {
-		ptr2[0] = '\0';
-		strcat(parsedCmd, ptr1);
-		strcat(parsedCmd, url);
-		ptr1 = ptr2 + 2;
-	}
-	strcat(parsedCmd, ptr1);
-	/* cwd to the download directory */
-	getcwd(cwd, PATH_MAX);
-	if(chdir(localpath)) {
-		_alpm_log(PM_LOG_WARNING, _("could not chdir to %s\n"), localpath);
-		pm_errno = PM_ERR_EXTERNAL_DOWNLOAD;
-		ret = -1;
-		goto cleanup;
-	}
-	/* execute the parsed command via /bin/sh -c */
-	_alpm_log(PM_LOG_DEBUG, "running command: %s\n", parsedCmd);
-	retval = system(parsedCmd);
-
-	if(retval == -1) {
-		_alpm_log(PM_LOG_WARNING, _("running XferCommand: fork failed!\n"));
-		pm_errno = PM_ERR_EXTERNAL_DOWNLOAD;
-		ret = -1;
-	} else if(retval != 0) {
-		/* download failed */
-		_alpm_log(PM_LOG_DEBUG, "XferCommand command returned non-zero status "
-				"code (%d)\n", retval);
-		ret = -1;
-	} else {
-		/* download was successful */
-		if(usepart) {
-			rename(tempfile, destfile);
-		}
-		ret = 0;
-	}
-
-cleanup:
-	chdir(cwd);
-	if(ret == -1) {
-		/* hack to let an user the time to cancel a download */
-		sleep(2);
-	}
-	FREE(destfile);
-	FREE(tempfile);
-
-	return(ret);
-}
-
 static int download(const char *url, const char *localpath,
 		time_t mtimeold, time_t *mtimenew) {
-	int ret;
-
-	/* We have a few things to take into account here.
-	 * 1. If we have both internal/external available, choose based on
-	 * whether xfercommand is populated.
-	 * 2. If we only have external available, we should first check
-	 * if a command was provided before we drop into download_external.
-	 */
-	if(handle->xfercommand == NULL) {
+	if(handle->fetchcb == NULL) {
 #if defined(INTERNAL_DOWNLOAD)
-		ret = download_internal(url, localpath, mtimeold, mtimenew);
+		handle->fetchcb = download_internal;
 #else
 		RET_ERR(PM_ERR_EXTERNAL_DOWNLOAD, -1);
 #endif
-	} else {
-		ret = download_external(url, localpath, mtimeold, mtimenew);
 	}
-	return(ret);
+	return handle->fetchcb(url, localpath, mtimeold, mtimeold);
 }
 
 /*
diff --git a/lib/libalpm/handle.c b/lib/libalpm/handle.c
index 813f439..3566889 100644
--- a/lib/libalpm/handle.c
+++ b/lib/libalpm/handle.c
@@ -105,6 +105,15 @@ alpm_cb_download SYMEXPORT alpm_option_get_dlcb()
 	return handle->dlcb;
 }
 
+alpm_cb_fetch SYMEXPORT alpm_option_get_fetchcb()
+{
+	if (handle == NULL) {
+		pm_errno = PM_ERR_HANDLE_NULL;
+		return NULL;
+	}
+	return handle->fetchcb;
+}
+
 alpm_cb_totaldl SYMEXPORT alpm_option_get_totaldlcb()
 {
 	if (handle == NULL) {
@@ -204,15 +213,6 @@ alpm_list_t SYMEXPORT *alpm_option_get_ignoregrps()
 	return handle->ignoregrp;
 }
 
-const char SYMEXPORT *alpm_option_get_xfercommand()
-{
-	if (handle == NULL) {
-		pm_errno = PM_ERR_HANDLE_NULL;
-		return NULL;
-	}
-	return handle->xfercommand;
-}
-
 unsigned short SYMEXPORT alpm_option_get_nopassiveftp()
 {
 	if (handle == NULL) {
@@ -258,6 +258,15 @@ void SYMEXPORT alpm_option_set_dlcb(alpm_cb_download cb)
 	handle->dlcb = cb;
 }
 
+void SYMEXPORT alpm_option_set_fetchcb(alpm_cb_fetch cb)
+{
+	if (handle == NULL) {
+		pm_errno = PM_ERR_HANDLE_NULL;
+		return;
+	}
+	handle->fetchcb = cb;
+}
+
 void SYMEXPORT alpm_option_set_totaldlcb(alpm_cb_totaldl cb)
 {
 	if (handle == NULL) {
@@ -519,12 +528,6 @@ int SYMEXPORT alpm_option_remove_ignoregrp(const char *grp)
 	return(0);
 }
 
-void SYMEXPORT alpm_option_set_xfercommand(const char *cmd)
-{
-	if(handle->xfercommand) FREE(handle->xfercommand);
-	if(cmd) handle->xfercommand = strdup(cmd);
-}
-
 void SYMEXPORT alpm_option_set_nopassiveftp(unsigned short nopasv)
 {
 	handle->nopassiveftp = nopasv;
diff --git a/lib/libalpm/handle.h b/lib/libalpm/handle.h
index ad7666d..89fc457 100644
--- a/lib/libalpm/handle.h
+++ b/lib/libalpm/handle.h
@@ -40,6 +40,7 @@ typedef struct _pmhandle_t {
 	alpm_cb_log logcb;      /* Log callback function */
 	alpm_cb_download dlcb;  /* Download callback function */
 	alpm_cb_totaldl totaldlcb;  /* Total download callback function */
+	alpm_cb_fetch fetchcb; /* Download file callback function */
 
 	/* filesystem paths */
 	char *root;              /* Root path, default '/' */
@@ -57,7 +58,6 @@ typedef struct _pmhandle_t {
 	/* options */
 	unsigned short usesyslog;    /* Use syslog instead of logfile? */ /* TODO move to frontend */
 	unsigned short nopassiveftp; /* Don't use PASV ftp connections */
-	char *xfercommand;        /* External download command */
 	unsigned short usedelta;     /* Download deltas if possible */
 } pmhandle_t;
 
diff --git a/src/pacman/conf.h b/src/pacman/conf.h
index 466d983..650b0f9 100644
--- a/src/pacman/conf.h
+++ b/src/pacman/conf.h
@@ -20,6 +20,11 @@
 #define _PM_CONF_H
 
 #include <alpm.h>
+#if defined(HAVE_SYS_SYSLIMITS_H)
+#include <sys/syslimits.h> /* PATH_MAX */
+#else
+#define PATH_MAX 1024
+#endif
 
 typedef struct __config_t {
 	unsigned short op;
@@ -71,6 +76,7 @@ typedef struct __config_t {
 	unsigned short cleanmethod; /* select -Sc behavior */
 	alpm_list_t *holdpkg;
 	alpm_list_t *syncfirst;
+	char xfercommand[PATH_MAX]; /* external download command */
 } config_t;
 
 /* Operations */
diff --git a/src/pacman/pacman.c b/src/pacman/pacman.c
index 59916d6..0d6c897 100644
--- a/src/pacman/pacman.c
+++ b/src/pacman/pacman.c
@@ -573,6 +573,99 @@ static void setrepeatingoption(const char *ptr, const char *option,
 	pm_printf(PM_LOG_DEBUG, "config: %s: %s\n", option, p);
 }
 
+/** External fetch callback */
+static int _download_with_xfercommand(const char *url, const char *localpath,
+		time_t mtimeold, time_t *mtimenew) {
+	int ret = 0;
+	int retval;
+	int usepart = 0;
+	char *ptr1, *ptr2;
+	char origCmd[PATH_MAX];
+	char parsedCmd[PATH_MAX] = "";
+	char cwd[PATH_MAX];
+	char *destfile, *tempfile, *filename;
+	int len;
+
+	if(!config->xfercommand) {
+		return -1;
+	}
+
+	filename = strrchr(url, '/');
+	if(!filename) {
+		return -1;
+	} else {
+		filename++; /* omit leading slash */
+	}
+
+	len = strlen(localpath) + strlen(filename) + 1;
+	destfile = calloc(len, sizeof(*destfile));
+	snprintf(destfile, len, "%s%s", localpath, filename);
+
+	len += 5; /* ".part" */
+	tempfile = calloc(len, sizeof(*tempfile));
+	snprintf(tempfile, len, "%s.part", destfile);
+
+	strncpy(origCmd, config->xfercommand, sizeof(origCmd));
+	/* replace all occurrences of %o with fn.part */
+	ptr1 = origCmd;
+	while((ptr2 = strstr(ptr1, "%o"))) {
+		usepart = 1;
+		ptr2[0] = '\0';
+		strcat(parsedCmd, ptr1);
+		strcat(parsedCmd, tempfile);
+		ptr1 = ptr2 + 2;
+	}
+	strcat(parsedCmd, ptr1);
+	/* replace all occurrences of %u with the download URL */
+	strncpy(origCmd, parsedCmd, sizeof(origCmd));
+	parsedCmd[0] = '\0';
+	ptr1 = origCmd;
+	while((ptr2 = strstr(ptr1, "%u"))) {
+		ptr2[0] = '\0';
+		strcat(parsedCmd, ptr1);
+		strcat(parsedCmd, url);
+		ptr1 = ptr2 + 2;
+	}
+	strcat(parsedCmd, ptr1);
+	/* cwd to the download directory */
+	getcwd(cwd, PATH_MAX);
+	if(chdir(localpath)) {
+		pm_printf(PM_LOG_DEBUG, "could not chdir to %s\n", localpath);
+		ret = -1;
+		goto cleanup;
+	}
+	/* execute the parsed command via /bin/sh -c */
+	pm_printf(PM_LOG_DEBUG, "running command: %s\n", parsedCmd);
+	retval = system(parsedCmd);
+
+	if(retval == -1) {
+		pm_printf(PM_LOG_DEBUG, "running XferCommand: fork failed!\n");
+		ret = -1;
+	} else if(retval != 0) {
+		/* download failed */
+		pm_printf(PM_LOG_DEBUG, "XferCommand command returned non-zero status "
+				"code (%d)\n", retval);
+		ret = -1;
+	} else {
+		/* download was successful */
+		if(usepart) {
+			rename(tempfile, destfile);
+		}
+		ret = 0;
+	}
+
+cleanup:
+	chdir(cwd);
+	if(ret == -1) {
+		/* hack to let an user the time to cancel a download */
+		sleep(2);
+	}
+	free(destfile);
+	free(tempfile);
+
+	return(ret);
+}
+
 /* The real parseconfig. Called with a null section argument by the publicly
  * visible parseconfig so we can recall from within ourself on an include */
 static int _parseconfig(const char *file, const char *givensection,
@@ -736,7 +829,8 @@ static int _parseconfig(const char *file, const char *givensection,
 							pm_printf(PM_LOG_DEBUG, "config: logfile: %s\n", ptr);
 						}
 					} else if (strcmp(key, "XferCommand") == 0) {
-						alpm_option_set_xfercommand(ptr);
+						strncpy(config->xfercommand, ptr, sizeof(config->xfercommand));
+						alpm_option_set_fetchcb(_download_with_xfercommand);
 						pm_printf(PM_LOG_DEBUG, "config: xfercommand: %s\n", ptr);
 					} else if (strcmp(key, "CleanMethod") == 0) {
 						if (strcmp(ptr, "KeepInstalled") == 0) {
-- 
1.6.1



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